ALBERT

Description: Climate change can make extreme drought and flood events more frequent, while damming large rivers can alter the hydrological regime by making droughts more prolonged and floods less intense. Together, both factors can affect aquatic communities. Here, the variation of Chironomidae community attributes between extreme floods and droughts in a neotropical floodplain river was investigated. The hypothesis that the abundance, richness, diversity and variability attributes of the Chironomidae community are reduced after extreme events was tested. Sampling took place quarterly from 2000 to 2012, although only a few years were selected to investigate our predictions. Twelve sampling periods were selected, which were divided into years in which, El Niño (extreme flood) and La Niña (extreme drought) phenomena occurred. In the Paraná River, three points were determined for the collection of benthic material, in transect: right bank, center and left bank of the river. We recorded 75 morphospecies of Chironomidae. The most common taxa in periods of extreme flooding were Djalmabatista sp 2, Lopescladius sp 1 and Tanytarsus type E. For periods of extreme drought, the most common taxa were Polypedilum (Tripodura) sp 4, Polypedilum sp 3 and Lopescladius sp 1. A composition and attributes of the Chironomidae community in the Paraná River varied between before and after extreme flood and drought events. Attributes such as Shannon-Wiener abundance, richness and diversity were reduced after extreme floods and, in contrast, tended to increase after extreme drought events (except Shannon diversity). Thus, it can be stated that the evaluated flood and drought events, despite being extreme, have different consequences in the Chironomidae community of the Paraná River. Given the environmental and global conditions we experience today, including climate change and dams, extreme events could be even more frequent in aquatic ecosystems. Therefore, it is essential to understand the consequences of extreme flood and drought events on ecosystems with high biodiversity and that provide relevant ecosystem services such as floodplain rivers.

Description: As mudanças climáticas podem tornar eventos de secas e cheias extremas mais frequentes, enquanto barramentos de grandes rios podem alterar o regime hidrológico por tornar as secas mais prolongadas e as cheias menos intensas. Em conjunto, ambos fatores podem afetar as comunidades aquáticas. Aqui, a variação dos atributos da comunidade de Chironomidae entre as cheias e secas extremas em um rio de planície de inundação neotropical. Testou-se a hipótese de que os atributos abundância, riqueza, diversidade e variabilidade da comunidade de Chironomidae são reduzidos após eventos extremos. As amostragens ocorreram trimestralmente 2000 a 2012, embora apenas alguns anos foram selecionados para investigar nossas predições. Selecionou-se 12 períodos de amostragem, que foram divididos em anos que ocorreram fenômenos de El Niño (cheia extrema) e La Niña (seca extrema). No rio Paraná foram determinados três pontos para coleta do material bentônico, em transecto: margem direita, centro e margem esquerda do rio. Registrou-se 75 morfoespécies de Chironomidae. Os táxos mais comuns nos períodos de cheia extrema foram Djalmabatista sp 2, Lopescladius sp 1 e Tanytarsus tipo E. Para os períodos de seca extrema, os táxons mais comuns foram Polypedilum (Tripodura) sp 4, Polypedilum sp 3 e Lopescladius sp 1. A composição e os atributos da comunidade de Chironomidae no rio Paraná variaram entre antes e depois de eventos de cheia e seca extremas. Os atributos, como abundância, riqueza e diversidade de Shannon-Wiener, foram reduzidos após cheias extremas e em contrapartida, tenderam a aumentar após eventos de seca extrema (exceto diversidade de Shannon). Pode-se afirmar que os eventos de cheias e secas avaliados, apesar de extremos, acarretam em diferentes consequências na comunidade de Chironomidae do rio Paraná. Considerando que as condições ambientais e globais que vivenciamos hoje, incluindo mudanças climáticas e barragens, os eventos extremos poderão ser ainda mais frequentes nos ecossistemas aquáticos. Portanto, é fundamental compreendermos as consequências dos eventos de cheia e seca extremas em ecossistemas com elevada biodiversidade e que fornecem relevantes serviços ecossistêmicos como rios de planícies de inundação.

Description: Masters

Description: Decomposition is a process of great importance to the ecosystem. Macroinvertebrates together with fungi and bacteria play a very important role in the cycling of organic matter. Through decomposition, nutrients that make up the organisms can be reused and macroinvertebrates act by fractionating the organic matter in this process. The exotic species Hydrilla verticillata (L.f) Royle usually causes problems in various regions of the globe such as economic damage in hydroelectric plants. This exotic species competes with native species and can facilitates new invasions. The objective of the present work is to evaluate how the colonization of macroinvertebrates occurs during the decomposition of H. verticillata and E. najas macrophytes, as well as other community attributes during the process such as density, richness, Shannon diversity and Pielou evenness. The experiment was carried out in Garças Lake and the macrophytes were collected in Paraná River. Macrophytes were dried at room temperature and 5 g of each species were added in two types of litterbags, one thin mesh (0.5 mm) and another with thick mesh (4 mm), totalling 100 litterbags. The litterbags were fixed at 5 points in the lake and removed each 4 days. In the laboratory the litterbags were washed with a 0.2 μm mesh sieve, the decomposing material was sorted and the remainder was oven dried for further decay calculation. There was no significant difference in community attributes, except when time was applied assigned to analysis. The decomposition was similar in both species because both had similar characteristics, including phylogenetic proximity. The most observed taxon during the process was Chironomidae. Thus, it is worth noting that more studies are needed to elucidate questions related to the colonization process and quantify the degradation of organic matter of exotic and native species in the Upper Paraná River floodplain.

Description: A decomposição é um processo de grande importâcia para os ecossistemas, e os macroivertebrados juntamente com fungos e bactérias possuem um importante papel na ciclagem da matéria orgânica. Pela decomposição, os nutrientes que compõem os organismos podem ser novamente reutilizados, e os macroinvertebrados atuam fracionando essa matéria orgânica. A espécie exótica Hydrilla verticillata (L.f) Royle é uma espécie de macrófita submersas que atualmente tem causado problemas em diversas regiões do globo. Além de causar prejuízos econômicos em usinas hidroelétricas H. verticillata causa prejuízos para as espécies nativas devido a competição por recursos, o que pode facilitar novas invasões. Avaliou-se como ocorre a colonização de macroinvertebrados durante a decomposição das macrófitas H. verticillata e E. najas, além de avaliar outros atributos de comunidade durante o processo como, por exemplo, densidade, riqueza, diversidade de Shannon e equitabilidade de Pielou. O experimento foi realizado na Lagoa das Garças e as macrófitas foram coletadas no Rio Paraná. Após a coleta, as plantas foram secas em temperatura ambiente. Foram acondicionadas 5 g de material seco de cada espécie em dois tipos de litterbag, um com malha fina (0,5mm) e outro com malha grossa (4 mm), totalizando 100 litterbags. Os litterbags foram fixados em 5 pontos na lagoa e retirados em um intervalo de 4 em 4 dias. Em laboratório, os litterbags foram lavados com auxílio de peneira de malha de 0,2 μm. O material em decomposição foi triado e o restante foi seco em estufa para posterior cálculo de decaimento. Não houve diferença significativa nos atributos de comunidade, exceto quando o tempo foi aplicado como uma variável à análise. A decomposição foi similar nas duas espécies devido a ambas possuírem características semelhantes. Talvez, a proximidade filogenética entre as macrófitas possa ter gerado a similaridade dos resultados obtidos durante o experimento. O táxon mais observado durante o processo foi de Chironomidae e o processo de colonização ocorreu de forma muito semelhante para ambos os tratamentos. Os tipos de malhas mostraram resultados parecidos, pois podem não ter influenciado a colonização e a entrada dos macroinvertebrados durante o processo de decomposição. Desse modo, a colonização dos invertebrados não dependeu das espécies de macrófita e/ou tipo de malha. Por isso ressalta-se a importância de novos estudos para melhor direcionar questões voltadas para a colonização e quantificar a degradação da matéria orgânica relativa a espécies exóticas e nativas na planície de inundação do alto rio Paraná.

Description: Masters

Description: The success of biological invasions depends on overcoming environmental filters. After the filters are transposed and subsequently established, invasive species can reach high densities and cause impacts, such as loss of biodiversity and damage to the functioning of ecosystems. The golden mussel (Limnoperna fortunei) is an invasive bivalve in South America and presents high densities in invaded environments. It has a planktonic larval stage, divided into five stages, and an encrusting adult. The larval stage is considered the main propagule of the species. It is known that abiotic factors act differently on larval stages, as these present morphological and physiological differences. Some works shown the ability of L. fortunei to select groups and functional traits of phytoplankton species, but these studies are experimental and with adult representatives. Considering that larvae are the main propagule of the species, therefore, abiotic filters act primarily on them, we sought to (i) evaluate the population structure of L. fortunei larvae and its relationship with environmental factors in lotic environments in the floodplain of the Upper Paraná River. In addition, considering that larvae can reach high density values, we also sought to (ii) identify the potential impacts of high larval densities on the taxonomic and functional diversity of phytoplankton, and their effects on ecosystem functioning. The results showed differences in the age pyramid between the evaluated environments, and found that most environmental filters act on the early larval stages. Among these filters, turbidity stands out. We also identified a negative effect of L. fortunei larval density on the functional and taxonomic diversity of the phytoplankton community. The effects of larval density on these facets of phytoplankton diversity resulted in indirect negative effects on the biomass stock of the community of these producers. It's expected that knowledge about the filters that control larval densities of L. fortunei can contribute to the control and management of the species, in order to avoid major impacts on the phytoplankton, and consequently, on the environment.

Description: O sucesso das invasões biológicas depende da superação filtros ambientais. Após a transposição dos filtros e consequente estabelecimento, as espécies invasoras podem atingir altas densidades e ocasionar impactos, como perda de biodiversidade e prejuízos ao funcionamento dos ecossistemas. O mexilhão-dourado (Limnoperna fortunei) é um bivalve invasor na América do Sul e apresenta elevadas densidades nos ambientes invadidos. Apresenta fase larval planctônica, dividida em cinco estágios, e adulta incrustante. A fase larval é considerada o principal propágulo da espécie. É sabido que os fatores abióticos atuam diferentemente sobre os estágios larvais, dado que estes apresentam diferenças morfológicas e fisiológicas. Alguns trabalhos evidenciaram a capacidade de L. fortunei em selecionar grupos e traços funcionais das espécies de fitoplâncton, porém esses estudos são experimentais e com representantes adultos. Considerando que as larvas são o principal propágulo da espécie, logo, os filtros abióticos agem primariamente sobre elas e buscou-se (i) avaliar a estruturação populacional das larvas de L. fortunei e sua relação com os fatores ambientais em ambientes lóticos da planície de inundação do alto rio Paraná. Ainda, considerando que as larvas podem atingir elevados valores de densidade também buscou-se (ii) identificar os potenciais impactos das altas densidades larvais sobre a diversidade taxonômica e funcional de fitoplâncton, e seus reflexos sobre o funcionamento ecossitêmico. Os resultados evidenciaram diferenças na pirâmide etária entre os ambientes avaliados, e constatou-se que a maioria dos filtros ambientais age sobre os estágios larvais iniciais. Dentre esses filtros, destaca-se a turbidez. Também identificou-se o efeito negativo da densidade larval de L. fortunei sobre a diversidade funcional e taxonômica da comunidade de fitoplâncton. Os efeitos da densidade larval sobre essas facetas da diversidade do fitoplâncton resultaram em efeitos negativos indiretos sobre o estoque de biomassa da comunidade desses produtores. Espera-se que o conhecimento sobre os filtros que controlam as densidades larvais de L. fortunei possa contribuir para o controle e manejo da espécie, a fim de evitar maiores impactos sobre o fitoplancton, e consequentemente, sobre o ambiente.

Description: PhD

Description: We describe seven new species of Physocypria sensu latu from three of the main Brazilian floodplains: Gen. 1 spec. A gen. et spec. nov. and Gen. 1 spec. B gen. et spec. nov. from the Upper Paraná River floodplain and the South Matogrossense Pantanal, Gen. 2 spec. C gen. et spec. nov., Gen. 1 spec. D gen. et spec. nov. and Gen. 2 spec. E gen. et spec. nov. from the South Matogrossense Pantanal only and Gen. 1 spec. F gen. et spec. nov. and Gen. 1 spec. G gen. et spec. nov. only from the Amazon River floodplain. All new species here described were found in sexual populations. Generally, the new species have a short and suboval carapace, with the left valve overlapping the right valve on all sides, except for the dorsal side in some species. The morphology of hemipenis and prehensile palps, together with the shape of the valves, were most important to distinguish the species. However, several other morphological characters from limb chaetotaxy are discussed, e.g., the absence in all new species of the short accompanying seta of the five natatory setae on antenna; the presence in all new species of a long seta next to the two a-seta on the first thoracopod and the presence/absence or length of specific setae on second and third thoracopod. We discuss the taxonomic position of the seven new species by evaluating the validity of extant genera, especially of Keysercypria Karanovic, 2011, and foreshadow that our seven new species represent two new genera of Cyclocypridinae.

Description: Sete novas espécies de Physocypria sensu latu foram descritas de três das principais planícies brasileiras: Gen. 1 spec. A gen. et spec. nov. e Gen. 1 spec. B gen. et spec. nov. da planície de inundação do alto rio Paraná e do Pantanal Sul Matogrossense, Gen. 2 spec. C gen. et spec. nov., Gen. 1 spec. D gen. et spec. nov. e Gen. 2 spec. E gen. et spec. nov. somente do Pantanal Sul Matogrossense e Gen. 1 spec. F gen. et spec. nov. e Gen. 1 spec. G gen. et spec. nov. somente da planície de inundação do rio Amazonas. Todas as novas espécies aqui descritas foram encontradas em populações sexuadas. Em geral, as novas espécies têm uma carapaça curta e suboval, com a valva esquerda sobrepondo a valva direita em todos os lados, com exceção do lado dorsal em algumas espécies. A morfologia do hemipênis e dos palpos preênseis, juntamente com a forma das valvas, foram as mais importantes para distinguir as espécies. A ausência em todas as novas espécies das cerdas curtas que acompanham as cinco cerdas natatórias nas antenas; a presença em todas as novas espécies de uma cerda longa ao lado das duas a-cerdas no primeiro toracópode e a presença/ausência ou comprimento de cerdas específicas no segundo e terceiro toracópodes são características presentes nos apêndices utilizadas para distinção dos novos gêneros e espécies. Discutiu-se a posição taxonômica das sete novas espécies avaliando a validade dos gêneros existentes, especialmente da Keysercypria Karanovic, 2011, e concluiu-se que nossas sete novas espécies representam dois novos gêneros de Cyclocypridinae.

Description: Masters

Description: Biological invasions have been occurring at a faster pace as a result of anthropic actions. At the same time, climate change can increase invasion rates, and also favor invading organisms. One of the predictions for climate change is the increase in periods of drought, in some regions of the planet. In this way, environments that suffer from these disorders become more susceptible to invasion by aquatic plants, especially those that are adapted to different types of habitats. Within this context, the objectives were: (i) to determine the response of a native species (Hymenachne pernambucensis) and another invasive species (Urochloa arrecta) to extreme drought, and (ii) to test whether the interspecific competition between them is affected by stress caused by drought. An in situ experiment was carried out, in which the biomass and the length of the species were different for different levels of drought, in which the invasive species was superior to the native species. However, the intensity of relative competition had only different aerial biomass between species, but in this case the invasive species showed a preference for growth in monoculture than in polyculture. It was concluded, then, that the invasive species U. arrecta has greater resilience to droughts than the native species H. pernambucensis. However, the native species showed greater competitive ability. These results may explain the high dominance of this invasive species in the invaded sites, due to its better resistance to disturbances. In the same way, it demonstrates that native species can reduce the invasion rates of this species, considering that it does not grow well in the presence of neighbors.

Description: Invasões biológicas vêm ocorrendo em um ritmo mais acelerado como resultado de ações antrópicas. Simultaneamente, as mudanças climáticas podem potencializar as taxas de invasão, e ainda favorecer organismos invasores. Uma das previsões para as mudanças climáticas é o aumento dos períodos de seca, em algumas regiões do planeta. Desta forma, ambientes que sofrem esses distúrbios se tornam mais suscetíveis à invasão por plantas aquáticas, em especial por aquelas que estão adaptadas a diversos tipos de habitats. Dentro deste contexto, os objetivos foram de: (i) determinar a resposta de uma espécie nativa (Hymenachne pernambucensis) e outra invasora (Urochloa arrecta) a uma seca extrema, e (ii) testar se a competição interespecífica entre ambas é afetada pelo estresse provocado pela seca. Foi realizado um experimento in situ, no qual a biomassa e o comprimento das espécies foram diferentes para diferentes níveis de seca, em que a espécie invasora foi superior a espécie nativa. Porém, a intensidade de competição relativa teve apenas a biomassa aérea diferente entre as espécies, mas nesse caso a espécie invasora demonstrou preferência por crescimento em monocultura do que em policultura. Concluiu-se, então, que a espécie invasora U. arrecta apresenta maior resiliência a secas do que a espécie nativa H. pernambucensis. Porém, a espécie nativa demonstrou maior habilidade competitiva. Esses resultados podem explicar a alta dominância dessa espécie invasora nos locais invadidos, devido a esta resistir melhor aos distúrbios. De mesmo modo, demonstra que espécies nativas podem reduzir as taxas de invasão dessa espécie, tendo em vista que ela não cresce bem na presença de vizinhos.

Description: Masters

Description: Efficient compositional models are required to simulate underground gas storage in porous formations where, for example, gas quality (such as purity) and loss of gas due to dissolution are of interest. We first extend the concept of vertical equilibrium (VE) to compositional flow, and derive a compositional VE model by vertical integration. Second, we present a hybrid model that couples the efficient compositional VE model to a compositional full‐dimensional model. Subdomains, where the compositional VE model is valid, are identified during simulation based on a VE criterion that compares the vertical profiles of relative permeability at equilibrium to the ones simulated by the full‐dimensional model. We demonstrate the applicability of the hybrid model by simulating hydrogen storage in a radially symmetric, heterogeneous porous aquifer. The hybrid model shows excellent adaptivity over space and time for different permeability values in the heterogeneous region, and compares well to the full‐dimensional model while being computationally efficient, resulting in a runtime of roughly one‐third of the full‐dimensional model. Based on the results, we assume that for larger simulation scales, the efficiency of this new model will increase even more.

Description: Key Points: A compositional vertical equilibrium model is coupled to its full‐dimensional counterpart. A criterion is developed to adaptively identify and assign regions where the vertical equilibrium model is applicable during simulation. A test case of hydrogen storage in a heterogeneous porous aquifer demonstrates efficiency and accuracy of the hybrid model.

Description: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659

Description: https://git.iws.uni-stuttgart.de/dumux-pub/Becker2021b.git

Description: Species are heterogeneously distributed and environmental changes, such as the construction of dams or extreme climate events, can modify the dynamics of aquatic organisms. Understanding the processes that drive diversity, across long time periods, can help in the establishment of increasingly accurate conservation measures. This thesis evaluated the patterns of β diversity and metacommunity structure at different spatial and temporal scales in three independent studies in the Upper Paraná river floodplain, Brazil. The first analyzed the seasonal variation of zooplankton β and Elements of Metacommunity Structure [EMS] of zooplankton, over four years (two years of prolonged drought and two years of extreme flooding), and on a smaller (sub-basins) and a larger scale (floodplain). Regardless of the hydrological period and spatial scale, zooplanktonic metacommunity structure remained practically constant throughout the four years, with the predominance of the Clementsian pattern. The predominance of the Clementsian pattern suggests that the associations of zooplankton species in the floodplain responded similarly to the environmental gradient and that the responses differed among species groups. In the second, the taxonomic (LCBD-t) and functional (LCBD-f) ecological uniqueness of zooplankton over 19 years was determined in lakes and lotic systems of two sub-basins (dammed and free-flowing), in addition to investigating which processes (temporal, environmental and biological) drive LCBD-t and LCBD-f. Regardless of the characteristics of each sub-basin, the highest LCBD-t and LCBD-f were related to lower species and trait richness, respectively. The temporal processes were the main drivers of the ecological uniqueness of zooplankton, and they were more important than the biological processes (phytoplankton biovolume and fish biomass, representing food resource and potential predation, respectively). Finally, it was tested whether, in a dammed sub-basin, a prolonged drought makes aquatic metacommunities (phytoplankton, zooplankton, and fish) more similar over time than a period that includes extreme flood events. Only zooplankton underwent homogenization during this period. The β diversity of phytoplankton and fish did not change between different hydrological periods, indicating that the dispersion type (passive or active) does not interfere with drought homogenization. The response between the biological groups was different, reinforcing that the groups are not surrogates of each other. The greater β diversity in the period with extreme floods shows, at least for zooplankton, the importance of the flood pulse, reducing the negative effects of prolonged drought in a dammed sub-basin. The results showed the predominance of a metacommunity pattern resulting from high turnover (Clementsian), indicating that conservation measures should include a greater number of sites, including those with less richness, as they may have a different composition (〉 LCBD). We also emphasize the importance of considering different scales, as each can provide unique insights. It is important that biodiversity studies consider β diversity to understand the mechanisms that drive the metacommunity in the face of environmental changes, especially over longer time scales.

Description: As espécies estão distribuídas de forma heterogênea e alterações ambientais, como a construção de reservatórios ou eventos climáticos extremos, podem modificar a dinâmica dos organismos aquáticos. Entender os processos que impulsionam a diversidade, em longos períodos de tempo, pode auxiliar no estabelecimento de medidas de conservação cada vez mais precisas. Esta tese avaliou os padrões de diversidade β e estrutura de metacomunidade em diferentes escalas espaciais e temporais em três estudos independentes na planície de inundação do Alto rio Paraná, Brasil. No primeiro foi analisado a variação sazonal da diversidade β e Elementos da Estrutura da Metacomunidade [EMS] do zooplâncton, durante quatro anos (dois anos de seca prolongada e dois anos com inundação extrema), e em uma menor (sub-bacias) e maior escala (planície de inundação). Independente do período hidrológico e da escala, a estrutura da metacomunidade do zooplâncton se manteve praticamente constante ao longo dos quatro anos, com predomínio do padrão Clementsiano. A predominância desse padrão sugere que as associações de espécies responderam de forma semelhante ao gradiente ambiental e que as respostas diferiram entre os grupos de espécies. No segundo foi determinado a singularidade ecológica taxonômica (LCBD-t) e funcional (LCBD-f) do zooplâncton ao longo de 19 anos em lagos e sistemas lóticos de duas sub-bacias (represada e não represada), além de investigar quais processos (temporais, ambientais e biológicos) impulsionam a LCBD-t e LCBD-f. Independentemente das características de cada sub-bacia, os maiores LCBD-t e LCBD-f foram relacionados a menor riqueza de espécies e de traços, respectivamente. Os processos temporais foram os principais impulsionadores da singularidade ecológica do zooplâncton, sendo mais importante do que os processos biológicos (biovolume do fitoplâncton e biomassa dos peixes, representando recurso alimentar e potencial predador, respectivamente). Por último, foi testado se em uma sub-bacia represada, um período de seca prolongada torna as comunidades aquáticas (fitoplâncton, zooplâncton e peixes) mais semelhantes ao longo do tempo do que um período com inundações extremas. Apenas o zooplâncton sofreu homogeneização nesse período. A diversidade β do fitoplâncton e dos peixes não diferiu entre os períodos hidrológicos, indicando que o tipo de dispersão (passivo ou ativo) não interfere na homogeneização da seca. Como a resposta entre os grupos biológicos foi diferente, sugere-se que os grupos não são substitutos uns dos outros. A maior diversidade β no período com inundações extremas mostra, pelo menos para o zooplâncton, a importância do pulso de inundação, reduzindo os efeitos negativos da seca prolongada em uma sub-bacia represada. Os resultados mostraram a predominância de um padrão de metacomunidade resultante de alto turnover (Clementsiano), indicando que medidas de conservação devem incluir um maior número de locais, inclusive aqueles com menor riqueza, uma vez que podem ter composição distinta (〉 LCBD). Reforçamos também a importância de considerar diferentes escalas, uma vez que cada uma pode fornecer insights exclusivos. É importante que estudos de biodiversidade considerem a diversidade β para compreender os mecanismos que impulsionam as metacomunidade diante das alterações ambientais, especialmente em escalas temporais mais longas.

Description: PhD

Description: Basal melting of marine‐terminating glaciers, through its impact on the forces that control the flow of the glaciers, is one of the major factors determining sea level rise in a world of global warming. Detailed quantitative understanding of dynamic and thermodynamic processes in melt‐water plumes underneath the ice‐ocean interface is essential for calculating the subglacial melt rate. The aim of this study is therefore to develop a numerical model of high spatial and process resolution to consistently reproduce the transports of heat and salt from the ambient water across the plume into the glacial ice. Based on boundary layer relations for momentum and tracers, stationary analytical solutions for the vertical structure of subglacial non‐rotational plumes are derived, including entrainment at the plume base. These solutions are used to develop and test convergent numerical formulations for the momentum and tracer fluxes across the ice‐ocean interface. After implementation of these formulations into a water‐column model coupled to a second‐moment turbulence closure model, simulations of a transient rotational subglacial plume are performed. The simulated entrainment rate of ambient water entering the plume at its base is compared to existing entrainment parameterizations based on bulk properties of the plume. A sensitivity study with variations of interfacial slope, interfacial roughness and ambient water temperature reveals substantial performance differences between these bulk formulations. An existing entrainment parameterization based on the Froude number and the Ekman number proves to have the highest predictive skill. Recalibration to subglacial plumes using a variable drag coefficient further improves its performance.

Description: Plain Language Summary: In a world of global warming, the melting of glaciers terminating as floating ice tongues into the oceans of Arctic and Antarctic regions allows those glaciers to flow faster and hence to make a considerable contribution to global mean sea‐level rise. Underneath the ice‐ocean interface, turbulent currents of the order of 10 m thickness (so‐called plumes) develop that transport the melt water from the grounding line where the glacier enters the ocean toward the calving front that marks the seaward end of the glacier. At its base, ambient relatively warm and salty ocean water is mixed into the plumes and is vertically transported toward the ice‐ocean interface, where the melting is increased due to the additional heat supply. Understanding these processes is essential for their incorporation into computer models for the prediction of such melt processes. In this study, an accurate simulation model for the water column is constructed that is able to consistently reproduce these processes. The algorithms developed here are proven to provide reliable results also for models with only a few grid points across the plume and can therefore be implemented into climate models with surface‐following coordinates to more accurately simulate future scenarios of sea level rise.

Description: Key Points: A vertically resolving model with second‐moment turbulence closure has been constructed for subglacial plumes. Convergent numerical formulations for the ocean‐to‐ice fluxes of momentum, freshwater and heat have been derived from an analytical model. Model results are consistent with bulk parameterizations for the entrainment of ambient water.

Description: Bundesministerium für Bildung und Forschung (BMBF) http://dx.doi.org/10.13039/501100002347

Description: https://doi.org/10.5281/zenodo.6203838

Description: The patterns and processes that cause a system of regionalization of organisms on the planet are historical and ecological hypotheses that biogeography seeks to elucidate. The Neotropical region is home to one of the greatest richness of freshwater fish in the world that exhibit distinct biogeographic patterns based on ecology, systematics, and evolution. Through methodologies within the scope of historical and/or ecological biogeography, the aims of this study are to present new approaches and contributions to the knowledge of the geographic distribution of freshwater fish in this region, investigating the evolutionary biogeography of Cnesterodontini and Anablepidae, as well as the spatial patterns of ichthyofauna beta-diversity in the Ivaí river basin, Paraná State. The results highlighted well-defined scenarios of the hydrological barriers formation, mainly between coastal basins and drainages that flow into the La Plata River system in South America. These findings enabled congruent relationships of biogeographic areas within the proposals for evolutionary diversification to the Neotropical freshwater fishes. Furthermore, dispersal events caused by headwater captures and sea-level changes satisfactorily complemented the biogeographic patterns and area relationships evidenced for other Neotropical fish lineages, showing similar diversification patterns in the Central Brazil drainages and in the Atlantic coast drainages. The results also showed strong spatial segregation of the ichthyofauna throughout the Ivaí River basin (upper Paraná River system) with emphasis on the mutual influences of niche- and dispersal-based processes. These findings can support new theoretical and methodological references for the main mechanisms and patterns specific to the metacommunities of aquatic organisms. Applying the results herein obtained in historical and ecological consonance has great potential to aid an effective management for the conservation of freshwater fish diversity, whether considering lineages with species at high risk of extinction or even river basins of fundamental importance for maintaining biodiversity and ecosystem functionality in continental aquatic environments.

Description: Os padrões e processos que ocasionam um sistema de regionalização dos organismos no planeta são hipóteses históricas e ecológicas que a biogeografia busca elucidar. A região Neotropical abriga uma das maiores riquezas de peixes de água doce do mundo, os quais exibem padrões biogeográficos distintos baseados na ecologia, sistemática e evolução. Por intermédio de metodologias dentro do escopo da biogeografia histórica e/ou ecológica, os objetivos deste estudo são apresentar novas abordagens e contribuições ao conhecimento da distribuição geográfica dos peixes de água doce nesta região ao investigar a biogeografia evolutiva de Cnesterodontini e Anablepidae, bem como os padrões espaciais da diversidade beta da ictiofauna na bacia do rio Ivaí, estado do Paraná. Os resultados destacaram cenários bem definidos da formação de barreiras hidrológicas, principalmente entre bacias hidrográficas costeiras e drenagens que fluem para o sistema do rio da Prata na América do Sul. Essas descobertas possibilitaram congruentes relacionamentos de áreas biogeográficas dentro das propostas de diversificação evolutiva à ictiofauna neotropical. Ainda, eventos de dispersão ocasionados por capturas de cabeceiras e mudanças no nível do mar complementaram satisfatoriamente os padrões biogeográficos e os relacionamentos de áreas evidenciados para outras linhagens de peixes neotropicais, apresentando padrões de diversificação semelhantes nas drenagens do Brasil Central e nas drenagens da costa atlântica. Os resultados também evidenciaram forte segregação espacial da ictiofauna ao longo da extensão da bacia do rio Ivaí (sistema do alto rio Paraná), com destaques às influências mútuas de processos baseados em nicho e dispersão. As novas descobertas podem subsidiar referenciais teóricos e metodológicos para os principais mecanismos e padrões específicos às metacomunidades de organismos aquáticos. A aplicação dos resultados aqui obtidos em consonância histórica e ecológica tem grande potencial ao auxílio de um manejo eficaz para a conservação da diversidade de peixes de água doce, seja considerando linhagens com espécies enquadradas em elevado risco de extinção, ou até mesmo bacias hidrográficas de fundamental importância para a manutenção da biodiversidade e funcionalidade ecossistêmica em ambientes aquáticos continentais.

Description: PhD

Description: The assessment of sustainable development in sub-watersheds plays a central role in rationalizing the decisions taken. A promising form of average indicators of this development is through indicators, and when many are used, they are usually aggregated into indices, which provide a simplified and multidimensional view of the system under analysis. Several sustainability indices for watersheds are proposed in the literature. However, incorporation of extraordinary indicators, that biodiversity, a gap is still a major upgrade. Therefore, the use of biodiversity indicators as representative of the environmental dimension constitutes an advance on the indices presented in the literature recently. The objective was to evaluate the sustainability gradient in the hydrographic basins of the Upper Paraná River, through an eco-environmental sustainability index of hydrographic sub-basins (ISE-sb) that incorporates protected ecological. For this purpose, the indicators selected based on the propositions of Agenda 2030 were identified in four dimensions of sustainability, economic, economic, environmental and thought through a process of sustainability: normal and social. Then, the importance of the indicators was considered, using the multi-criteria analysis based on the Hierarchical Process Analysis (HP) method. The ISE-sb was calculated by means of the weighted media between the sub-indices that represent as dimensions. Finally, we apply the Gi* statistic to identify hotspots and coldspots. The results show that among the dimensions of sustainability, the highest was the one that presented a positive amount of low values. The regions located in the eastern portion, or serra do mar, southern portion, and the Federal District formed sustainability hotspots, while the sub-basins located in the states of Goiás, Mato Grosso do Sul and Minas Gerais formed the sustainability coldposts. A sustainable spatial planning of the hydrographic sub-basins is recommended, adopting cold areas as priorities for sustainability. It highlights the main methodological limitation, a potential reproducibility of the tool in other spaces.

Description: A avaliação do desenvolvimento sustentável em sub-bacias hidrográficas tem um papel central na racionalização das tomadas de decisões. Uma forma promissora de medir esse desenvolvimento, é por meio de indicadores, e quando muitos indicadores são usados, eles são usualmente agregados em índices, que fornecem uma visão simplificadae multidimensional do sistema em análise. Diversos índices de sustentabilidade para bacias hidrográficas são propostos na literatura. Entretanto, a incorporação de indicadores ecológicos aquáticos, que agreguem aspectos da biodiversidade é, ainda, uma lacuna ainda a ser preenchida. Portanto, a utilização de indicadores de biodiversidade como representantes da dimensão ambiental, se constitui em um avanço aos índices recentemente apresentados na literatura. O objetivo ,foi avaliar o gradiente de sustentabilidade nas bacias hidrográficas do alto rio Paraná, por meio de um índice de sustentabilidade ecoambiental de sub-bacias (ISE-sb) que incorpora indicadores ecológicos aquáticos. Com esse propósito, os indicadores selecionados com base nas proposições da Agenda 2030, foram divididos em quatro dimensões de sustentabilidade: social, econômica, ecoambiental e ambiental negativo, e passaram por um processo de normalização e filtragem. Em seguida, foi ponderada a importância dos indicadores, utilizando-se da análise de multicritério baseada no método Análise de Processos Hierárquicos (AHP).O ISE-sb foi calculado por meio da média ponderada entre os subíndices que representam as dimensões. Por fim aplicamos a estatística espacial Gi* para identificar agrupamentos de hotspots e coldspots. Os resultados mostram que entre as dimensões da sustentabilidade, aquela que apresentou a maior quantidade de valores baixos, foia ambiental positiva. As regiões localizadas na porção leste, ou serra do mar, porção sul, e o Distrito Federal formaram hotspots de sustentabilidade, enquanto que as sub-bacias localizadas nos estados de Goiás, Mato Grosso do Sul e Minas Gerais formaram os coldposts de sustentabilidade. Recomenda-se um planejamento espacial sustentável das sub-bacias hidrográficas, adotando as áreas de coldspots como prioritárias para sustentabilidade. Evidencia a principal limitação metodológica, a potencial reprodutibilidade da ferramenta em outros espaços.

Description: Masters

Description: Human activities have caused degradation of aquatic ecosystems and reduced biodiversity. The dams in particular directly impact the spatial and temporal variation of aquatic communities, and especially the phytoplankton community that responds quickly and efficiently to changes in the environment. The impact of a dam in an Amazon river (Jirau Hydroelectric Power Plant) on the spatial and temporal variation of the composition (beta diversity) of phytoplankton was investigated, from October 2009 to July 2017. The hypothesis was tested that the bus modifies beta diversity on a local and regional scale, and alters each location's contribution to beta diversity. The contribution of the sites to the beta diversity was evaluated as a function of the distance from the bus and the environmental heterogeneity. The phytoplankton composition was different between the phases before, fill and after the damming. Biotic homogenization was verified in the tributaries closest to the dam. The more distant sites presented greater contribution to diversity, but were associated with lower values of richness. The dam caused unidirectional changes, locally and regionally, that is, the community moved to a new state over time, and also caused biotic homogenization locally. The impact of the dam was observed only on the tributaries, indicating that run-of-river dams have a greater impact on the tributaries than on the main channel.

Description: As atividades humanas têm causado degradação dos ecossistemas aquáticos e reduz a biodiversidade. Os barramentos em especial, impactam diretamente a variação espacial e temporal das comunidades aquáticas, e especialmente a comunidade fitoplanctônica que responde de forma rápida e eficiente às mudanças do ambiente. Investigou-se o impacto de um barramento em um rio amazônico (Usina Hidrelétrica de Jirau) sobre a variação espacial e temporal da composição (diversidade beta) do fitoplâncton, no período de outubro de 2009 a julho de 2017. Foi testado a hipótese de que o barramento modifica a diversidade beta em escala local e regional, e altera a contribuição de cada local à diversidade beta. Avaliou-se a contribuição dos locais para a diversidade beta em função da distância do barramento e da heterogeneidade ambiental. A composição fitoplanctônica foi diferente entre as fases antes, enchimento e após o barramento. Verificou-se homogeneização biótica nos tributários mais próximos a barragem. Os locais mais distantes apresentaram maior contribuição a diversidade, mas foram associados a menores valores de riqueza. O barramento causou mudanças unidirecionais, localmente e regionalmente, ou seja, a comunidade passou para um novo estado ao longo do tempo, e também causou homogeneização biótica localmente. Observou-se o impacto do barramento somente nos tributários, indicando que as barragens a fio de água têm maior impacto nos tributários do que no canal principal.

Description: Masters

Description: Die Ausgabe der Geowissenschaftlichen Mitteilungen vom September 2022 enthält die Themenblöcke: GEOfokus: Rohstoffe für die deutsche Energiewende, GEOaktiv (Wirtschaft, Beruf, Forschung und Lehre), GEOlobby (Gesellschaften, Verbände, Institutionen), GEOreport (Geowissenschaftliche Öffentlichkeitsarbeit, Tagungsberichte, Ausstellungen, Exkursionen, Publikationen), GEOszene (Würdigungen, Nachrufe).

Description: DFG, SUB Göttingen

Description: journal

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pold, G., Baillargeon, N., Lepe, A., Rastetter, E. B., & Sistla, S. A. Warming effects on arctic tundra biogeochemistry are limited but habitat-dependent: a meta-analysis. Ecosphere, 12(10), (2021): e03777, https://doi.org/10.1002/ecs2.3777.

Description: Arctic tundra consists of diverse habitats that differ in dominant vegetation, soil moisture regimes, and relative importance of organic vs. inorganic nutrient cycling. The Arctic is also the most rapidly warming global area, with winter warming dominating. This warming is expected to have dramatic effects on tundra carbon and nutrient dynamics. We completed a meta-analysis of 166 experimental warming study papers to evaluate the hypotheses that warming changes tundra biogeochemical cycles in a habitat- and seasonally specific manner and that the carbon (C), nitrogen (N), and phosphorus (P) cycles will be differentially accelerated, leading to decoupling of elemental cycles. We found that nutrient availability and plant leaf stoichiometry responses to experimental warming were variable and overall weak, but that both gross primary productivity and the plant C pool tended to increase with growing season warming. The effects of winter warming on C fluxes did not extend into the growing season. Overall, although warming led to more consistent increases in C fluxes compared to N or P fluxes, evidence for decoupling of biogeochemical cycles is weak and any effect appears limited to heath habitats. However, data on many habitats are too sparse to be able to generalize how warming might decouple biogeochemical cycles, and too few year-round warming studies exist to ascertain whether the season under which warming occurs alters how ecosystems respond to warming. Coordinated field campaigns are necessary to more robustly document tundra habitat-specific responses to realistic climate warming scenarios in order to better understand the mechanisms driving this heterogeneity and identify the tundra habitats, communities, and soil pools most susceptible to warming.

Description: Funding for this project was provided by NSF Signals in the Soil grant number 1841610 to SAS and ER. SAS and ER conceived of and acquired funding for the project. NB completed the literature search.

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Stunz, E., Fetcher, N., Lavretsky, P., Mohl, J., Tang, J., & Moody, M. Landscape genomics provides evidence of ecotypic adaptation and a barrier to gene flow at treeline for the arctic foundation species Eriophorum vaginatum. Frontiers in Plant Science, 13, (2022): 860439, https://doi.org/10.3389/fpls.2022.860439.

Description: Global climate change has resulted in geographic range shifts of flora and fauna at a global scale. Extreme environments, like the Arctic, are seeing some of the most pronounced changes. This region covers 14% of the Earth’s land area, and while many arctic species are widespread, understanding ecotypic variation at the genomic level will be important for elucidating how range shifts will affect ecological processes. Tussock cottongrass (Eriophorum vaginatum L.) is a foundation species of the moist acidic tundra, whose potential decline due to competition from shrubs may affect ecosystem stability in the Arctic. We used double-digest Restriction Site-Associated DNA sequencing to identify genomic variation in 273 individuals of E. vaginatum from 17 sites along a latitudinal gradient in north central Alaska. These sites have been part of 30 + years of ecological research and are inclusive of a region that was part of the Beringian refugium. The data analyses included genomic population structure, demographic models, and genotype by environment association. Genome-wide SNP investigation revealed environmentally associated variation and population structure across the sampled range of E. vaginatum, including a genetic break between populations north and south of treeline. This structure is likely the result of subrefugial isolation, contemporary isolation by resistance, and adaptation. Forty-five candidate loci were identified with genotype-environment association (GEA) analyses, with most identified genes related to abiotic stress. Our results support a hypothesis of limited gene flow based on spatial and environmental factors for E. vaginatum, which in combination with life history traits could limit range expansion of southern ecotypes northward as the tundra warms. This has implications for lower competitive attributes of northern plants of this foundation species likely resulting in changes in ecosystem productivity.

Description: This research was made possible by funding provided by NSF/PLR-1417645 to MM. The Botanical Society of America Graduate Student Research Award and the Dodson Research Grant from the Graduate School of the University of Texas at El Paso provided assistance to ES. The grant 5U54MD007592 from the National Institute on Minority Health and Health Disparities (NIMHD), a component of the National Institutes of Health (NIH) provided bioinformatics resources and support of JM.

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rastetter, E., Kwiatkowski, B., Kicklighter, D., Plotkin, A., Genet, H., Nippert, J., O’Keefe, K., Perakis, S., Porder, S., Roley, S., Ruess, R., Thompson, J., Wieder, W., Wilcox, K., & Yanai, R. N and P constrain C in ecosystems under climate change: role of nutrient redistribution, accumulation, and stoichiometry. Ecological Applications, (2022): e2684, https://doi.org/10.1002/eap.2684.

Description: We use the Multiple Element Limitation (MEL) model to examine responses of 12 ecosystems to elevated carbon dioxide (CO2), warming, and 20% decreases or increases in precipitation. Ecosystems respond synergistically to elevated CO2, warming, and decreased precipitation combined because higher water-use efficiency with elevated CO2 and higher fertility with warming compensate for responses to drought. Response to elevated CO2, warming, and increased precipitation combined is additive. We analyze changes in ecosystem carbon (C) based on four nitrogen (N) and four phosphorus (P) attribution factors: (1) changes in total ecosystem N and P, (2) changes in N and P distribution between vegetation and soil, (3) changes in vegetation C:N and C:P ratios, and (4) changes in soil C:N and C:P ratios. In the combined CO2 and climate change simulations, all ecosystems gain C. The contributions of these four attribution factors to changes in ecosystem C storage varies among ecosystems because of differences in the initial distributions of N and P between vegetation and soil and the openness of the ecosystem N and P cycles. The net transfer of N and P from soil to vegetation dominates the C response of forests. For tundra and grasslands, the C gain is also associated with increased soil C:N and C:P. In ecosystems with symbiotic N fixation, C gains resulted from N accumulation. Because of differences in N versus P cycle openness and the distribution of organic matter between vegetation and soil, changes in the N and P attribution factors do not always parallel one another. Differences among ecosystems in C-nutrient interactions and the amount of woody biomass interact to shape ecosystem C sequestration under simulated global change. We suggest that future studies quantify the openness of the N and P cycles and changes in the distribution of C, N, and P among ecosystem components, which currently limit understanding of nutrient effects on C sequestration and responses to elevated CO2 and climate change.

Description: This material is based on work supported by the National Science Foundation under Grant No. 1651722 as well through the NSF LTER Program 1637459, 2220863 (ARC), 1637686 (NWT), 1832042 (KBS), 2025849 (KNZ), 1636476 (BNZ), 1637685 (HBR), 1832210 (HFR), 2025755 (AND). We also acknowledge NSF grants 1637653 and 1754126 (INCyTE RCN), and DOE grant DESC0019037. We also acknowledge support through the USDA Forest Service Hubbard Brook Experimental Forest, North Woodstock, New Hampshie (USDA NIFA 2019-67019-29464) and Pacific Northwest Research Station, Corvallis, Oregon.

Description: Dataset: Symbiodiniaceae communities in corals with ITS-2 rDNA amplicon sequencing

Description: Symbiodiniaceae communities were investigated at three locations on the Great Barrier Reef in October 2014. Acropora millepora samples from Davies Reef lagoon (18°30′3.96′′S, 147°22′48′′E), Rib Reef (18°28′53.4′′S, 146°52′24.96′′E), and Pandora Island (18°48′45′′S, 146°25′59.16′′E), were exposed to various stressors including pCO2, heat, bacteria, all of these, or none of these (control). This dataset lists accessions and collection information for ITS-2 rDNA amplicon data that are available at the National Center for Biotechnology Information (NCBI) under BioProject PRJNA596498. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/844431

Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1635798

Description: Dataset: Experimental coral treatments

Description: Coral samples from reefs in Mo'orea, French Polynesia were exposed to various experimental treatments to quantify how different environmental stressors impact the coral health and microbial community structure of the corals. Environmental stressors included increased temperature and nutrients as well as exudate released from corals when they bleach. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/843188

Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1635798, NSF Division of Ocean Sciences (NSF OCE) OCE-1635913

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Winters, G., Teichberg, M., Reuter, H., Viana, I. G., & Willette, D. A. Editorial: seagrasses under times of change. Frontiers in Plant Science, 13, (2022): 870478, https://doi.org/10.3389/fpls.2022.870478.

Description: Awareness of the ecological importance of seagrasses is growing due to recent attention to their role in carbon sequestration as a potential blue carbon sink (Fourqurean et al., 2012; Bedulli et al.), as well as their role in nutrient cycling (Romero et al., 2006), sediment stabilization (James et al., 2019), pathogen filtration (Lamb et al., 2017), and the formation of essential habitats for economically important marine species (Jackson et al., 2001; Jones et al.). Despite their importance and the increasing public and scientific awareness of seagrasses, simultaneous global (e.g., ocean warming, increase in frequency and severity of extreme events, introduction and spread of invasive species) and local (e.g., physical disturbances, eutrophication, and sedimentation) anthropogenic stressors continue to be the main causes behind the ongoing global decline of seagrass meadows (Orth et al., 2006; Waycott et al., 2009).

Description: This research was partially funded through the BMBF project SEANARIOS (Seagrass scenarios under thermal and nutrient stress: FKZ 03F0826A) to HR and MT. MT was partially funded through the DFG project SEAMAC (Seagrass and macroalgal community dynamics and performance under environmental change; TE 1046/3-1). IV was supported by a postdoctoral research grant Juan de la Cierva-Incorporación (IJC2019-040554-I) and from MCIN/AEI /10.13039/501100011033 (Spain).

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chavarry, J. M., Law, K. L., Barton, A. D., Bowlin, N. M., Ohman, M. D., & Choy, C. A. Relative exposure to microplastics and prey for a pelagic forage fish. Environmental Research Letters, 17(6), (2022): 064038, https://doi.org/10.1088/1748-9326/ac7060.

Description: In the global ocean, more than 380 species are known to ingest microplastics (plastic particles less than 5 mm in size), including mid-trophic forage fishes central to pelagic food webs. Trophic pathways that bioaccumulate microplastics in marine food webs remain unclear. We assess the potential for the trophic transfer of microplastics through forage fishes, which are prey for diverse predators including commercial and protected species. Here, we quantify Northern Anchovy (Engraulis mordax) exposure to microplastics relative to their natural zooplankton prey, across their vertical habitat. Microplastic and zooplankton samples were collected from the California Current Ecosystem in 2006 and 2007. We estimated the abundance of microplastics beyond the sampled size range but within anchovy feeding size ranges using global microplastic size distributions. Depth-integrated microplastics (0–30 m depth) were estimated using a depth decay model, accounting for the effects of wind-driven vertical mixing on buoyant microplastics. In this coastal upwelling biome, the median relative exposure for an anchovy that consumed prey 0.287–5 mm in size was 1 microplastic particle for every 3399 zooplankton individuals. Microplastic exposure varied, peaking within offshore habitats, during the winter, and during the day. Maximum exposure to microplastic particles relative to zooplankton prey was higher for juvenile (1:23) than adult (1:33) anchovy due to growth-associated differences in anchovy feeding. Overall, microplastic particles constituted fewer than 5% of prey-sized items available to anchovy. Microplastic exposure is likely to increase for forage fishes in the global ocean alongside declines in primary productivity, and with increased water column stratification and microplastic pollution.

Description: This work originated from the Plastic Awareness Global Initiative (PAGI) international workshop, hosted by the Center for Marine Biodiversity and Conservation (CMBC) at Scripps Institution of Oceanography at the University of California San Diego in 2018, with support from Igor Korneitchouk and the Wilsdorf Mettler Future Foundation. We thank the workshop participants for early discussions and a collaborative meeting space. We thank Kelly Lance for her illustration contributions, and the SIO Communications Office for their support. We thank Miriam Doyle and Ryan Rykaczewski for their assistance in data acquisition, and we thank Penny Dockry and Stuart Sandin of CMBC for administrative and logistical support. Julia Chavarry was supported by the San Diego Fellowship. This paper is a contribution from the California Current Ecosystem Long Term Ecological Research site, supported by the National Science Foundation.

Description: Invasive species can have many negative impacts on the biodiversity, ecosystem services, human health and the economy, and therefore need to be managed. An amphibious weed of global importance, Alternanthera philoxeroides, and the macroecological patterns of its biological control were evaluated using one of its main specialist herbivores, Agasicles hygrophila. This was considered the first successful case of biological control of an aquatic plant, although it is not equally effective on a global scale. Due to their different environmental tolerances and the greater phenotypic plasticity of the plant, the distribution of both species do not always overlap in the globe, creating geographic variability in the efficiency of biocontrol. The first approach was to analyze the current global potential distribution of A. philoxeroides and A. hygrophila to seek the areas of overlaps and gaps between them. The overlapping areas would be the most relevant for using A. hygrophila as alligator weed biological control in the globe. However, in response of climate change, it seems that the alligator weed is worryingly spreading across the globe, which can worsen in future scenarios and alter its distribution in the next decades. The second approach evaluated the effects of climate change on the global distribution of A. philoxeroides and A. hygrophila. New distribution areas for both species in future global warming scenarios and new overlapping and non-overlapping areas across the globe were identified. Species Distribution Models (SDMs) were applied in both chapters to predict the potential distribution of the two species in present and future scenarios considering different environmental predictors in each one. Currently, the southeast coast of the USA, southeast China and New South Wales, Australia are the most favorable areas in the world to apply alligator weed biocontrol, while the west coast and mid-latitudes in the east of the USA and the eastern Australia are not favorable. The results were corroborated by reports in the literature that demonstrated successful control in overlapping areas and failures in non-overlapping areas of the models’ distributions. However, while general geographic patterns will hold in future scenarios, it is predicted a major northward expansion of the alligator weed, but not of the insect, especially in the USA, Canada, Europe, China, South Korea and Japan, which will create a new zone of low or no control efficiency at higher latitudes. These macroecological patterns will help direct efforts to apply the biological control for the alligator weed not only today, but also in future climate change scenarios.

Description: Espécies invasoras podem causar muitos impactos negativos na biodiversidade, nos serviços ecossistêmicos, na saúde humana e na economia e, portanto, precisam ser manejadas. Avaliou-se uma erva daninha anfíbia de importância global, Alternanthera philoxeroides, e nos padrões macroecológicos de seu controle biológico usando um de seus principais herbívoros especialistas, Agasicles hygrophila. Este foi considerado o primeiro caso bem sucedido de controle biológico de uma macrófita, embora não seja igualmente eficaz em escala global. Devido às suas diferentes tolerâncias ambientais e à maior plasticidade fenotípica da planta, a distribuição de ambas as espécies nem sempre se sobrepõe no globo, criando variabilidade geográfica na eficiência do biocontrole. O primeiro enfoque foi analisar a distribuição potencial global atual de A. philoxeroides e A. hygrophila para buscar as áreas de sobreposição e não sobreposição entre elas. As áreas sobrepostas seriam as mais relevantes para o uso de A. hygrophila como controle biológico da erva-de-jacaré no globo. Entretanto, em resposta às mudanças climáticas, a erva-de-jacaré está se expandindo de forma preocupante pelo globo, o que pode agravar em cenários futuros e alterar sua distribuição nas próximas décadas. O segundo enfoque avaliou-se os efeitos das mudanças climáticas na distribuição global de A. philoxeroides e A. hygrophila. Identificou-se as novas áreas de distribuição para ambas as espécies em cenários futuros de aquecimento global e as novas áreas sobrepostas e não sobrepostas em todo o globo. Modelos de Distribuição de Espécies (MDEs) foram aplicados em ambas as abordagens para predizer a distribuição potencial das duas espécies em cenários presentes e futuros considerando diferentes preditores ambientais em cada um. Atualmente, a costa sudeste dos EUA, sudeste da China e Sidnei, Austrália, são as áreas mais favoráveis no mundo para aplicar o biocontrole da erva-de-jacaré, enquanto a costa oeste e latitudes médias no leste dos EUA e no leste da Austrália não são favoráveis. Os resultados foram corroborados por relatos na literatura que demonstraram controle bem-sucedido em áreas sobrepostas e mal-sucedido em áreas não sobrepostas das distribuições dos modelos. Entretanto, embora os padrões geográficos gerais se mantenham em cenários futuros, é prevista uma grande expansão da erva-de-jacaré, mas não do inseto, para o norte, especialmente nos EUA, Canadá, Europa, China, Coreia do Sul e Japão, o que criará uma nova zona de baixa ou nenhuma eficiência de controle em latitudes mais altas. Esses padrões macroecológicos ajudarão a direcionar os esforços para aplicar o controle biológico da erva-de-jacaré não apenas atualmente, mas também em cenários futuros de mudanças climáticas.

Description: PhD

Description: The industrial advance of Europe between the 19th and 20th centuries resulted in major environmental impacts. Among these impacts, the deposition of acid compounds through acid rain stands out, and this phenomenon led to the acidification of water bodies. However, from the 1980s on, with the application of stricter environmental regulations, a gradual recovery of abiotic parameters began, including pH values, which began to return to less acidic ranges. Thus, we investigated the responses of the benthic community to the gradual recovery of abiotic variables after years of intense acidification, analyzing changes in community structure and, specifically, variations in beta diversity. The study was developed with data from streams in Wales, collected and provided by two research projects that monitor the region's water bodies. The streams were classified according to abiotic characteristics and the surrounding vegetation (Acid Forest, Acid Moorland and Circumneutral Moorland). In the first approach, the community of 69 streams was analyzed, testing whether (i) the composition of macroinvertebrate communities differed among the types of environments and years analyzed; and whether (ii) in early years beta diversity among streams was lower than in more recent years, as well as in streams of a more acidic category. Samples were collected in 1984, 1995, and 2012, with the earliest year under the greatest influence of acidification. A segregation in macroinvertebrate composition was observed between 1984 and the other years, and this difference in community composition between the years suggests that environmental recovery with rising pH values, allowed the entry and establishment of new macroinvertebrate species in the streams. The lowest beta diversity value was also observed in 1984, indicating biotic homogenization in this period and an increase in community dissimilarity over time. In the second approach, we investigated the hypothesis that a gradual increase in temporal beta diversity (TBI) values occurs over time. This was done by sampling eight streams in Wales over the period 1985 to 2018, and comparing beta diversity between the reference year 1985 with all other years. There was an increase in TBI values over the years for all environments, showing evidence of biological recovery concomitant with restoration of abiotic values. The results contributed to the understanding that the biotic community also responds to environmental recovery, and there are different ways to evaluate this process, such as beta diversity. The importance of long-term research is emphasized so that such changes can be monitored.

Description: O avanço industrial da Europa entre os séculos XIX e XX resultou em grandes impactos ambientais. Dentre esses impactos, destaca-se a deposição de compostos ácidos através da chuva ácida, e tal fenômeno levou à acidificação de corpos d’água. Contudo, a partir da década de 1980, com a aplicação de normas ambientais mais rígidas, teve início uma recuperação gradual dos parâmetros abióticos, incluindo os valores de pH, que começaram a retornar para faixas menos ácidas. Investigou-se as respostas da comunidade bentônica diante da recuperação gradual das variáveis abióticas após anos de intensa acidificação, analisando mudanças na estrutura da comunidade e, especificamente, as variações da diversidade beta. Os estudos foram desenvolvidos com dados de riachos do País de Gales, coletados e cedidos por dois projetos de pesquisas galeses que monitoram os corpos aquáticos da região, sendo os riachos classificados de acordo com as características abióticas e da vegetação do entorno (Acid Forest, Acid Moorland e Circumneutral Moorland). Na primeira abordagem, analisou-se a comunidade de 69 riachos, testando se (i) a composição das comunidades difere entre os tipos de ambientes e anos analisados; e se (ii) nos anos iniciais a diversidade beta entre os riachos foi menor do que nos anos mais recentes, assim como nos riachos de uma categoria mais ácida. As amostras foram coletadas em 1984, 1995 e 2012, sendo o ano mais antigo sob maior influência da acidificação. Observou-se uma segregação na composição da biota entre 1984 e os demais anos, e essa diferença na composição da comunidade entre os anos sugere que a recuperação ambiental com ascensão nos valores de pH, permitiu a entrada e estabelecimento de novas espécies de macroinvertebrados nos riachos. O menor valor de diversidade beta também foi observado em 1984, indicando homogeneização biótica neste período e aumento da dissimilaridade das comunidades com o tempo. Na segunda abordagem, investigou-se a hipótese de que ocorre um aumento gradativo nos valores de diversidade beta temporal (TBI) ao longo do tempo. Para tanto, foram amostrados oito riachos no País de Gales no período entre 1985 e 2018, e comparado a diversidade beta dos riachos entre o ano referência 1985 com todos os demais anos. Houve um aumento dos valores de TBI ao longo dos anos para todos ambientes, mostrando indícios de recuperação biológica concomitante com o restabelecimento dos valores abióticos. Os resultados contribuíram para o entendimento de que a comunidade biótica também responde à recuperação ambiental. Sendo a diversidade beta uma das formas de se avaliar tal processo. E ressalta-se a importância de pesquisas de longa duração para que tais respostas bióticas possam ser monitoradas.

Description: PhD

Description: Macrophytes are widely recognized for increasing habitat complexity and driving a relevant role in structuring communities in aquatic ecosystems. We investigated how the density, coverage and diversity of macrophytes can influence multiple aspects of fish community, including functional alpha and beta diversity, foraging efficiency, trophic niche breadth and overlap, total abundance and biomass of fish, as well as of certain species and sizes of fish. We used 30 macrophyte stands sampled in the littoral zone of a tropical river, as well as a dataset of 88 shallow temperate lakes. In the latter case, two spatial scales were considered (lake and points within a lake), since there is usually a negative relationship between fish and macrophyte coverage, and this relationship may be more evident at the point scale, while the effect is attenuated at the lake scale. The results showed that macrophytes can select functional characteristics of fish communities and influence their alpha and beta functional diversity. The highest values of functional alpha diversity occurred in intermediate macrophyte density and high macrophyte diversity. The variation in macrophyte density was strongly responsible for variations in functional beta diversity. Fish showed general trophic responses to the variation in macrophyte attributes, but these responses also depended on fish feeding habits, with herbivores niche breadth responding in the opposite way to omnivores. The increase in macrophyte density led to an increase in fish consumption of higher plants and foraging efficiency, and reduced trophic niche breadth. Fish niche overlap was higher at intermediate levels of macrophyte density. Fish responses depended on fish species identity, lake productivity and water depth. The deeper and more eutrophic the lakes, the more fish tended to occupy macrophyte-covered points within a lake. The results emphasize how aquatic plants can affect the fish community by influencing swimming, food availability and interactions between species, and that the relationship between fish and macrophytes can vary according to the scale of the study and the fish characteristics. The application of the results obtained here has great potential to help in projects of management and conservation of biodiversity, and in the choice of the best configurations of macrophyte stands for the maintenance of ichthyofauna.

Description: As macrófitas são amplamente reconhecidas por aumentarem a complexidade do habitat e exercerem papel relevante na estruturação das comunidades em ecossistemas aquáticos. Investigou-se como a densidade, cobertura e diversidade de macrófitas podem influenciar múltiplos aspectos da comunidade de peixes, incluindo diversidade alfa e beta funcional, eficiência de forrageamento, amplitude e sobreposição de nicho trófico, abundância e biomassa de total de peixes, bem como de determinadas espécies e tamanhos de peixes. Utilizou-se 30 bancos de macrófitas amostrados na zona litorânea de um rio tropical, bem como, um conjunto de dados de 88 lagos rasos temperados. Neste ultimo caso, foram consideradas duas escalas espaciais (lago e pontos dentro do lago), visto que geralmente há uma relação negativa entre peixes e a cobertura de macrófitas, e essa relação pode ser mais evidente na escala de ponto dentro do lago, enquanto o efeito é atenuado na escala de lago. Os resultados evidenciaram que as macrófitas podem selecionar características funcionais das comunidades de peixes e influenciar sua diversidade funcional alfa e beta. Os maiores valores de diversidade alfa funcional ocorreram em densidades intermediárias e elevada diversidade de macrófitas. A variação na densidade de macrófitas foi fortemente responsável pelas variações na diversidade beta funcional. Os peixes apresentaram respostas tróficas gerais à variação dos atributos das macrófitas, mas estas respostas também dependeram dos hábitos alimentares dos peixes, com a amplitude de nicho dos herbívoros respondendo de forma oposta à amplitude de onívoros. O aumento na densidade de macrófitas levou a um aumento no consumo de vegetais superiores pelos peixes e na eficiência de forrageamento, e reduziu a amplitude do nicho trófico. A sobreposição de nicho de peixes foi maior nos níveis intermediários de densidade de macrófitas. As respostas dos peixes dependeram da identidade da espécie de peixe, produtividade da lagoa e profundidade da água. Quanto mais profundos e eutróficos eram os lagos, mais os peixes tenderam a ocupar pontos cobertos por macrófitas dentro de um lago. Mediante os resultados, ressaltamos como as plantas aquáticas podem afetar a comunidade de peixes por influenciarem na natação, disponibilidade de alimento e interações entre as espécies, e que a relação entre peixe e macrófita pode variar de acordo com a escala do estudo e as características dos peixes considerados. A aplicação dos resultados aqui obtidos tem grande potencial de auxílio em projetos de manejo e conservação da biodiversidade, e na escolha das melhores configurações de bancos de macrófitas para a manutenção da ictiofauna.

Description: PhD

Description: Hydrogen is a promising alternative to carbon based energy carriers and may be stored in large quantities in subsurface storage deposits. This work assesses the impact of static (density and phase equilibria) and dynamic (viscosity and diffusion coefficients) properties on the pressure field during the injection and extraction of hydrogen in the porous subsurface. In a first step, we derive transport properties for water, hydrogen and their mixture using the Perturbed‐Chain Statistical Associating Fluid Theory equation of state in combination with an entropy scaling approach and compare model predictions to alternative models from the literature. Our model compares excellently to experimental transport coefficients and models from literature with a higher number of adjustable parameters, such as GERG2008, and shows a clear improvement over empirical correlations for transport coefficients of hydrogen. In a second step, we determine the effect of further model reduction by comparing our against a much simpler model applying empirical transport coefficients from the literature. For this purpose, hydrogen is periodically injected into and extracted out of a dome‐shaped porous aquifer under a caprock. Our results show that density and viscosity of hydrogen have the highest impact on the pressure field, and that a thermodynamic model like the new model presented here is essential for modeling the storage aquifer, while keeping the number of coefficients at a minimum. In diffusion‐dominated settings such as the diffusion of hydrogen through the caprock, our developed diffusion coefficients show a much improved dependence on temperature and pressure, leading to a more accurate approximation of the diffusive fluxes.

Description: Key Points: We model the phase behavior of pure hydrogen and the binary hydrogen‐water mixture using the Perturbed‐Chain Statistical Associating Fluid Theory equation of state. New entropy scaling relations for the transport properties of hydrogen and water and diffusion coefficients of their mixture are derived. The impact of the newly derived fluid properties is analyzed for a scenario of hydrogen storage in a porous aquifer.

Description: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659

Description: https://git.iws.uni-stuttgart.de/dumux-pub/sauerborn2020a

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pold, G., Kwiatkowski, B. L., Rastetter, E. B., & Sistla, S. A. Sporadic P limitation constrains microbial growth and facilitates SOM accumulation in the stoichiometrically coupled, acclimating microbe-plant-soil model. Soil Biology & Biochemistry, 165, (2022): 108489, https://doi.org/10.1016/j.soilbio.2021.108489.

Description: Requirements for biomass carbon (C), nitrogen (N), and phosphorus (P) constrain organism growth and are important agents for structuring ecosystems. Arctic tundra habitats are strongly nutrient limited as decomposition and recycling of nutrients are slowed by low temperature. Modeling interactions among these elemental cycles affords an opportunity to explore how disturbances such as climate change might differentially affect these nutrient cycles. Here we introduce a C–N–P-coupled version of the Stoichiometrically Coupled Acclimating Microbe-Plant-Soil (SCAMPS) model, “SCAMPS-CNP”, and a corresponding modified CN-only model, “SCAMPS-CN”. We compared how SCAMPS-CNP and the modified SCAMPS-CN models project a moderate (RCP 6.0) air warming scenario will impact tussock tundra nutrient availability and ecosystem C stocks. SCAMPS-CNP was characterized by larger SOM and smaller organism C stocks compared to SCAMPS-CN, and a greater reduction in ecosystem C stocks under warming. This difference can largely be attributed to a smaller microbial biomass in the CNP model, which, instead of being driven by direct costs of P acquisition, was driven by variable resource limitation due to asynchronous C, N, and P availability and demand. Warming facilitated a greater relative increase in plant and microbial biomass in SCAMPS-CNP, however, facilitated by increased extracellular enzyme pools and activity, which more than offset the metabolic costs associated with their production. Although the microbial community was able to flexibly adapt its stoichiometry and become more bacteria-like (N-rich) in both models, its stoichiometry deviated further from its target value in the CNP model because of the need to balance cellular NP ratio. Our results indicate that seasonality and asynchrony in resources affect predicted changes in ecosystem C storage under warming in these models, and therefore build on a growing body of literature indicating stoichiometry should be considered in carbon cycling projections.

Description: This work was funded by the National Science Foundation Signals in the Soil grant number 1841610 to SAS and EBR.

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Burnham, K. A., Nowicki, R. J., Hall, E. R., Pi, J., & Page, H. N. Effects of ocean acidification on the performance and interaction of fleshy macroalgae and a grazing sea urchin. Journal of Experimental Marine Biology and Ecology, 547, (2022): 151662, https://doi.org/10.1016/j.jembe.2021.151662.

Description: When predicting the response of marine ecosystems to climate change, it is increasingly recognized that understanding the indirect effects of ocean acidification on trophic interactions is as important as studying direct effects on organism physiology. Furthermore, comprehensive studies that examine these effects simultaneously are needed to identify and link the underlying mechanisms driving changes in species interactions. Using an onshore ocean acidification simulator system, we investigated the direct and indirect effects of elevated seawater pCO2 on the physiology and trophic interaction of fleshy macroalgae and the grazing sea urchin Lytechinus variegatus. Macroalgal (Dictyota spp.) biomass increased despite decreased photosynthetic rates after two-week exposure to elevated pCO2. Algal tissue carbon content remained constant, suggesting the use of alternative carbon acquisition pathways beneficial to growth under acidification. Higher C:N ratios driven by a slight reduction in N content in algae exposed to elevated pCO2 suggest a decrease in nutritional content under acidification. Urchin (L. variegatus) respiration, biomass, and righting time did not change significantly after six-week exposure to elevated pCO2, indicating that physiological stress and changes in metabolism are not mechanisms through which the trophic interaction was impacted. Correspondingly, urchin consumption rates of untreated macroalgae (Caulerpa racemosa) were not significantly affected by pCO2. In contrast, exposure of urchins to elevated pCO2 significantly reduced the number of correct foraging choices for ambient macroalgae (Dictyota spp.), indicating impairment of urchin chemical sensing under acidification. However, exposure of algae to elevated pCO2 returned the number of correct foraging choices in similarly exposed urchins to ambient levels, suggesting alongside higher C:N ratios that algal nutritional content was altered in a way detectable by the urchins under acidification. These results highlight the importance of studying the indirect effects of acidification on trophic interactions simultaneously with direct effects on physiology. Together, these results suggest that changes to urchin chemical sensing and algal nutritional quality are the driving mechanisms behind surprisingly unaltered urchin foraging behavior for fleshy macroalgae under joint exposure to ocean acidification. Consistent foraging behavior and consumption rates suggest that the trophic interaction between L. variegatus and fleshy macroalgae may be sustained under future acidification. However, increases in fleshy macroalgal biomass driven by opportunistic carbon acquisition strategies have the potential to cause ecological change, depending on how grazer populations respond. Additional field research is needed to determine the outcome of these results over time and under a wider range of environmental conditions.

Description: This work was supported by Mote Marine Laboratory Postdoctoral Fellowships (RJN and HNP), Becker Internship Funding, and philanthropic funds to ERH.

Description: Vlasov solvers that operate on a phase‐space grid are highly accurate but also numerically demanding. Coarse velocity space resolutions, which are largely unproblematic in particle‐in‐cell (PIC) simulations, can lead to numerical heating or oscillations in continuum Vlasov methods. To address this issue, we present a new dual Vlasov solver which is based on an established positivity preserving advection scheme for the update of the distribution function and an energy conserving partial differential equation solver for the kinetic update of mean velocity and temperature. The solvers work together via moment fitting during which the maximum entropy part of the distribution function is replaced by the solution from the partial differential equation solver. This numerical scheme makes continuum Vlasov methods competitive with PIC methods concerning computational cost and enables us to model large scale reconnection in Earth's magnetosphere with a fully kinetic continuum method. The simulation results agree well with measurements by the MMS spacecraft.

Description: Key Points: A moment fitting continuum Vlasov solver is presented that preserves positivity of the distribution function and conserves total energy. The method behaves well at low velocity space resolutions, making it competitive with PIC methods concerning computational cost. There is good agreement of the simulations with measurements of magnetic reconnection by the MMS spacecraft.

Description: Helmholtz Association (亥姆霍兹联合会致力) http://dx.doi.org/10.13039/501100009318

Description: https://vlasov.tp1.ruhr-uni-bochum.de/data/paper-JGR-2021

Description: Thiarids are pantropical gastropods endemic to South America and are found in lentic and lotic freshwater environments. These gastropods act as intermediate hosts for several species of digeneans. However, it is important to consider that there are difficulties for a correct identification of these digeneans in certain stages of the life cycle since the larvae have a reduced size and few morphological characteristics for diagnosis. In this way, techniques based on molecular markers become an extremely important tool, combining the use of ribosomal and mitochondrial regions. Considering that there are no records in the literature of studies involving parasites and gastropods as intermediate hosts in the Ivaí River, this study is the first regarding these relationships. Seventy-six specimens of gastropods were collected. Of these, 21 were parasitized. As for the parasites, 16 different morphotypes were found. The gastropod DNA was amplified using the COI marker. The gastropods showed genetic similarity with Aylacostoma chloroticum with different percentages of identity. As for the parasites, COI and 28S markers were used for DNA amplification. Four different taxa were characterized with both markers. With the mitochondrial marker it was possible to confirm only one genus among the digeneans found. However, the 28S ribosomal marker proved to be more effective for the identification of Ivaí River parasites, showing higher similarity values in relation to sequences available in the databases and lower values of genetic distance. In this way, it was possible to confirm the classification of the morphotypes into two distinct genera.

Description: Os tiarídeos são gastrópodes pantropicais endêmicos da América do Sul e são encontrados em ambientes de água doce lênticos e lóticos. Esses gastrópodes atuam como hospedeiros intermediários de várias espécies de digenéticos. No entanto, é importante considerar que existem dificuldades para uma identificação correta desses digenéticos em determinadas fases do ciclo de vida, visto que as larvas possuem um tamanho reduzido e poucas características morfológicas para diagnóstico. Dessa maneira, técnicas baseadas em marcadores moleculares tornam-se uma ferramenta de extrema importância, combinando a utilização de regiões ribossômicas e mitocondriais. Considerando que não há registros na literatura de estudos envolvendo parasitas e gastrópodes como hospedeiros intermediários no rio Ivaí, este estudo é o primeiro a respeito dessas relações. Foram coletados 76 espécimes de gastrópodes. Desses, 21 encontravam-se parasitados. Quanto aos parasitas, foram encontrados 16 morfotipos distintos. O DNA dos gastrópodes foi amplificado utilizando o marcador COI. Os gastrópodes apresentaram similaridade genética com Aylacostoma chloroticum com diferentes percentuais de identidade. Quanto aos parasitas, para amplificação do DNA foram utilizados os marcadores COI e 28S. Quatro taxa diferentes foram caracterizados com ambos os marcadores. Com o marcador mitocondrial foi possível confirmar apenas um gênero dentre os digenéticos encontrados. Todavia, o marcador ribossômico 28S se mostrou mais eficaz para a identificação dos parasitas do rio Ivaí, apresentando maiores valores de similaridade em relação a sequências disponíveis nos bancos de dados e menores valores de distância genética. Dessa maneira, foi possível confirmar a classificação dos morfotipos em dois gêneros distintos.

Description: Masters

Description: Ludwigia has some invasive macrophyte species that have not yet been explored under the scope of phylogeography, a promising area to understand the ecology of invasions using barcode molecular markers sensitive to intraspecific variations. Thus, it was theorized that barcode markers used in invasive species of Ludwigia occurring in non-native regions would be phylogeographically informative. Sequences of the molecular markers trnH-psbA, rbcL, matK and phyC from invasive populations of L. peploides and L. grandiflora were used as they are the only ones available in Genbank. A gene tree was generated by the Neighborn-Joining method and a haplotypic network by the Median-Joining method for each species. The trnH-psbA marker was the only phylogeographically informative marker for detecting intraspecific variations in the analyzed taxa. Three haplotypes were detected for L. grandiflora and two haplotypes for L. peploides. Three geographically distinct founder populations of L. grandiflora were introduced in Europe, with Hg1 shared with the US population, while L. peploides has a founder population in Europe and another in the US. The long history of the introduction of these species in Europe and the limited geographic scope of molecular sampling demonstrate that these data are underestimated. A search in the Web of Science database exposed a paucity of molecular data for invasive species of Ludwigia, highlighting the contribution of the results to the information on these haplotypic relationships in the context of invasive biology. Therefore, the detection of haplotypic diversity of invasive species of Ludwigia proved to be promising when investigated by the phylogeographic scope, supporting a better understanding of the management and ecology of these haplotypes in non-native areas.

Description: Ludwigia possui algumas espécies de macrófitas invasoras que ainda não foram exploradas sob o escopo da filogeografia, uma promissora área para compreender a ecologia das invasões utilizando marcadores moleculares barcode sensíveis a variações intraespecíficas. Assim, testou-se quais marcadores barcode utilizados em espécies invasoras de Ludwigia ocorrentes em regiões não nativas seriam filogeograficamente informativos. Utilizou-se sequências dos marcadores moleculares trnH-psbA, rbcL, matKe phyC de populações invasoras de L. peploides e L. grandiflora por serem as únicas disponíveis no Genbank. Gerou-se uma árvore gênica pelo método Neighborn-Joining e uma rede haplotípica pelo método Median-Joining para cada espécie. O marcador trnH-psbA foi o único informativo filogeograficamente por detectar variações intraespecíficas nos táxons analisados. Detectou-se três haplótipos para L. grandiflorae dois haplótipos para L. peploides. Três populações fundadoras geograficamente distintas de L. grandiflora foram introduzidas na Europa, sendo Hg1 compartilhado com a população estadunidense, enquanto L. peploidespossui uma população fundadora na Europa e outra nos EUA. O antigo histórico de introdução dessas espécies na Europa e a abrangência geográfica limitada da amostragem molecular demonstram que esses dados estão subestimados. Uma pesquisa feita na base de dados Web of Science expôs uma escassez de dados moleculares para espécies invasoras de Ludwigia, ressaltando a contribuição dos resultados quanto as informações sobre essas relações haplotípica no contexto da biologia das invasões. Portanto, a detecção da diversidade haplotípica de espécies invasoras de Ludwigia mostrou-se promissora quando investigada pelo escopo filogeográfico, subsidiando o melhor entendimento sobre o manejo e a ecologia desses haplótipos em áreas não nativas.

Description: Masters

Description: South America has fish endemic to continental fresh waters, but derived from clades predominantly and ancestrally distributed in marine environments, such as Platanichthys platana. This species is considered the smallest sardine of the Clupeidae with its type locality in the La Plata river. In 2007, there were the first records of P. platana in the upper Paraná river basin and in 2012 in the upper Paraná river floodplain. The variation in the length of specimens from this basin generated curiosity about their identity and origin of introduction. Sequences from the COI region of the specimens were used for genetic distance calculations, construction of gene trees and haplotype networks. The results obtained indicate that all analyzed specimens belong to P. platana. Eight haplotypes were found, some exclusive to the coastal basins of Santa Catarina, Rio Grande do Sul and Negro river basin. The basins of the La Plata river, the Lago and the upper Paraná river floodplain shared different haplotypes. The phylogeographic pattern presented in this study can be justified by the presence of populations of P. platana in the same paleoarea, before the geological process that configured the current architectures of the observed basins, by vicariance. During the Mesozoic and Cenozoic several vicarious events occurred between the coastal watersheds of Brazil that can be attributed to marine regressions and transgressions by continental lands. It is also assumed that specimens from the upper Paraná river floodplain were introduced to the region from Argentine regions.

Description: A América do Sul apresenta peixes endêmicos de águas doces continentais, mas derivados de clados predominantemente e ancestralmente distribuídos em ambientes marinhos, como Platanichthys platana. Essa espécie é considerada a sardinha de menor tamanho de Clupeidae com sua localidade-tipo no rio de La Plata. Em 2007, houve os primeiros registros de P. platana na bacia do alto rio Paraná e em 2012 na planície de inundação do alto rio Paraná. A variação do comprimento dos espécimes dessa bacia gerou curiosidade sobre sua identidade e origem de introdução. Sequências da região COI dos espécimes foram e utilizadas para cálculos de distância genética, construção de árvores gênicas e rede de haplótipos. Os resultados obtidos indicam que todos os exemplares analisados pertencem a P. platana. Oito haplótipos foram encontrados, alguns exclusivos dos exemplares das bacias litorâneas de Santa Catarina, do Rio Grande do Sul e bacia do rio Negro. As bacias do rio de La Plata, do Lago e da planície de inundação do alto rio Paraná compartilharam diferentes haplótipos. O padrão filogeográfico apresentado nesse estudo pode ser justificado pela presença de populações de P. platana em uma mesma paleoarea, antes do processo geológico que configurou as atuais arquiteturas das bacias observadas, pela vicariância. Durante o Mesozóico e Cenozóico vários eventos vicariantes ocorreram entre as bacias hidrográficas costeiras do Brasil que podem ser atribuídos às regressões e transgressões marinhas por terras continentais. Pressupõe-se também que os espécimes da planície de inundação do alto rio Paraná tenham sido introduzidos na região a partir de regiões argentinas.

Description: Masters

Description: Non native species can negatively affect the invaded environment. Often, these species have biological characteristics that benefit other non natives and facilitate their invasion, so knowing the facilitation mechanisms between invaders are useful to mitigate their damage to the ecosystem. Thus, in this study we tested the hypothesis that Pterygoplichthys ambrosettii, a non native catfish, has habits that can alter nutrient concentrations (phosphorus and nitrogen) in the water column, and positively affect the growth of an invasive macrophyte species in detriment of a native one, characterizing ecological facilitation among invasive species. Therefore, an experiment was conducted with six treatments and four replicas, using the invasive macrophyte Hydrilla verticillata and the native Egeria najas, in the presence and absence of P. ambrosettii, all with occurrence recorded in the upper Paraná River floodplain. The results showed that the treatments with P. ambrosettii had a lower amount of dissolved oxygen, higher electrical conductivity, higher concentration of chlorophyll-a, total phosphorus (TP) and inorganic nitrogen (NI). Macrophyte biomass was significantly higher in monoculture treatments with fish, with this effect being more intense for H. verticillata. When in the same treatment, in the absence of P. ambrosettii, H. verticillata showed greater biomass than E. najas, but with the fish presence, the macrophyte species did not differ in their biomass, indicating that the high concentration of nutrients makes the coexistence of these macrophytes possible. The results found will be useful for future actions to manage invasive species, especially in habitats where they co-occur.

Description: Espécies invasoras podem impactar negativamente o ambiente invadido. Frequentemente, estas espécies possuem características biológicas que beneficiam outras não nativas e facilitam sua invasão, portanto conhecer os mecanismos de facilitação entre invasoras é essencial para mitigar os danos ao ecossistema. Desta forma, neste estudo testamos a hipótese de que Pterygoplichthys ambrosettii, um cascudo invasor, com hábitos que podem alterar as concentrações de nutrientes (fósforo e nitrogênio) na coluna d'água, afeta positivamente o crescimento de uma espécie de macrófita invasora em detrimento de uma nativa, caracterizando a facilitação ecológica entre espécies invasoras. Para isso um experimento foi conduzido, utilizando a macrófita invasora Hydrilla verticillata e a nativa Egeria najas, na presença e ausência de P. ambrosettii (bem como ambas coocorrendo na presença e ausência do peixe), todos com ocorrência registrada na planície de inundação do alto rio Paraná. Os tratamentos com P. ambrosettii apresentaram menor quantidade de oxigênio dissolvido, maiores valores para a condutividade elétrica, clorofila-a, fósforo total (TP) e nitrogênio inorgânico (NI). A biomassa das macrófitas foi significativamente maior nos tratamentos de monocultura com peixe, sendo este efeito mais intenso para H. verticillata. Quando juntas na ausência de P ambrosettii, H. verticillata apresentou maior biomassa que E. najas, mas com a presença do peixe, as espécies não diferiram em sua biomassa, sugerindo que a alta concentração de nutrientes torna possível a coexistência das macrófitas. Os resultados encontrados se mostram úteis para o conhecimento da biologia destas espécies invasoras, assim como para futuras ações de manejo em pequenos habitats onde estas coocorrem.

Description: Masters

Description: In recent years, Spatial Markov Models have gained popularity in simulating solute transport in heterogeneous formations. They describe the transition times of particles between equidistant observation planes by statistical distributions, assuming correlation of the transit times of individual particles between subsequent steps. By this, the approach naturally captures preasymptotic solute dispersion. In this study, we analyze Spatial Markov Models assuming bivariate log‐normal distributions of the particle slowness (i.e., the inverse velocity) in subsequent transitions. The model is fully parameterized by the mean Eulerian velocity, the variance of the log‐slowness, and the correlation coefficient of log‐slowness in subsequent steps. We derive closed‐form expressions for distance‐dependent ensemble dispersion, which is defined in terms of the second‐central moments of the solute breakthrough curves. We relate the coefficients to the properties of the underlying log‐hydraulic conductivity field assuming second‐order stationarity. The results are consistent with linear stochastic theory in the limit of small log‐conductivity variances, while the approach naturally extends to high‐variance cases. We demonstrate the validity of the approach by comparison to three‐dimensional particle‐tracking simulations of advective transport in heterogeneous media with isotropic, exponential correlation structure for log‐conductivity variances up to five. This study contributes to relating solute dispersion to metrics of the porous‐medium structure in cases of strong heterogeneity.

Description: Key Points: We derive closed‐form expressions of ensemble dispersion in the spatial‐Markov framework of solute transport. The expressions are consistent with linear theory in the limit of small log‐conductivity variances, but extend to high‐variance cases. Comparison to particle‐tracking simulations of advective transport in 3‐D heterogeneous domains show excellent agreement.

Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Description: https://doi.org/10.5281/zenodo.6554308

Description: https://www.hsl.rl.ac.uk/catalogue/hsl_mi20.html

Description: Changes in water level influence the establishment and ecological interactions developed between aquatic macrophytes.With the aim of investigate how changes in water level, the density of the invasive macrophyte Urochloa arrecta and the species richness influence the establishment of Paspalum repens, we set up two experiments in a greenhouse with three water levels (high, medium and static) and two levels of density and species richness. At the end of the experiments, we measured the following response variables: leaf area surface, shoot biomass, root biomass, total biomass, shoot length, and root length of P. repens. Using the total biomass, we calculated the relative interaction index (RII) to verify the type of ecological interaction developed between P. repens and its neighbors species. Each response variable was analyzed with a two-way ANOVA. Among the results obtained, we highlight: i) the predominantly negative values of the RII, indicating competition between P. repens and its neighbors in all the conditions tested in this work and ii) positive values of leaf area surface and shoot biomass at water levels high, especially in the experiment that analyzed the effect of the density of U. arrecta on P. repens, which highlights the strategies adopted by this species to establish itself in environments with high densities of the invasive species in scenarios of water level changes. Finally, these results indicate the effects of changes in water level, density of U. arrecta and species richness on P. repens, contributing to the understanding of the dynamics of macrophyte communities in freshwater ecosystems.

Description: Mudanças do nível d’água influenciam o estabelecimento e as interações ecológicas desenvolvidas entre macrófitas aquáticas. Com o objetivo de investigar como mudanças no nível d’água, a densidade da macrófita invasora Urochloa arrecta e a riqueza de espécies influenciam no estabelecimento da macrófita nativa Paspalum repens, foram montados dois experimentos em casa de vegetação com três níveis d’água (alto, médio e estático) e dois níveis de densidade e riqueza de espécies. Ao final do experimento foram mensuradas as seguintes variáveis resposta: superfície da área foliar, biomassa aérea, biomassa da raiz, biomassa total, comprimento aéreo e comprimento da raiz de Paspalum repens. Utilizando a biomassa total, foi calculado o índice de interação relativa (RII) para verificar o tipo de interação ecológica desenvolvida entre P. repens e suas espécies vizinhas. Cada variável resposta foi analisada com uma Anova bifatorial. Dentre os resultados obtidos, destacamos: i) os valores preponderantemente negativos do RII, indicando competição de P. repens com suas vizinhas em todas as condições testadas neste trabalho e ii) valores positivos da superfície da área foliar e biomassa aérea em níveis d’água alto, especialmente no experimento que foi analisado o efeito da densidade de U. arrecta sobre P. repens, o que evidencia as estratégias adotadas por esta espécie para se estabelecer em ambientes com altas densidades da espécie invasora em cenários de mudanças do nível d’água. Esses resultados indicam, por fim, os efeitos da mudança do nível da água, da densidade de U. arrecta e da riqueza de espécies sobre P. repens, contribuindo para o entendimento da dinâmica das comunidades de macrófitas em ambientes aquáticos continentais.

Description: Masters

Description: Despite growing interest in the effects of non-native invasive species in changing alternative trophic states in shallow lakes, little is known when it comes to tropical regions. We carried out a systematic review to identify which terms, species, definitions and objectives were most addressed in these studies, as well as to identify possible global patterns and trends regarding the growth of these research over the years and the hot spots of publications. Our results showed that although there was a non-linear growth in the number of studies published in the last three decades regarding state shifts in freshwater environments, only a small number of them addresses the influence that non-native invasive species have in triggering trophic states changes in aquatic environments and even less in shallow lakes. In our discussion, we explore the possible reasons and consequences that these patterns bring to this area of ecology, as well as expand the results and make the work available so that it can be used as recomendation for future projects related to the topic.

Description: Lagos rasos são os ecossistemas de água doce mais abundantes do planeta, suportam elevada diversidade de espécies e proveem diversos serviços ecossistêmicos, porém, a dinâmica natural desses ecossistemas está ameaçada devido ao estabelecimento de espécies invasoras não nativas. Apesar do crescente interesse acerca dos impactos que espécies invasoras não nativas causam nos ecossistemas invadidos, pouco ainda se sabe sobre a influência delas para a estabilidade e mudança de estado trófico em lagos rasos. Foi realizada uma revisão sistematizada da literatura para identificar quais termos, espécies, definições e objetivos foram mais abordados nesses estudos, assim como identificar possíveis padrões e tendências globais quanto à distribuição das pesquisas ao longo dos anos e seu local de origem. Embora tenha havido um crescimento na quantidade de estudos publicados nas últimas três décadas sobre estados tróficos em ambientes aquáticos, apenas uma pequena quantidade deles aborda a influência das espécies invasoras nãonativas na mudança de estado trófico nestes ecossistemas. Foram exploradas as possíveis razões e as consequências que esses padrões e métodos trazem para essa área da ecologia, de forma que a discussão aqui feita sugere diversas recomendações para futuros trabalhos e pesquisadores considerarem.

Description: Masters

Description: Global climate change has as its main result an increase in the frequency and severity of extreme events, such as longer periods of drought, and more hot days throughout the year, which makes drought events even more severe. Certain plant species have a high invasive potential, which is due to their tolerance to adverse conditions and the recovery of their individuals after some disturbance, which increases the possibility of colonization and establishment in new environments, interfering with native communities. The effect of interspecific competition between the invasive plant Urochloa mutica and the native species Panicum dichotomiflorum was experimentally analyzed on its establishment, resistance and resilience, simulating conditions of extreme water events and the distribution of Panicum dichotomiflorum and Urochloa mutica, particularly in protected areas environmental. The results obtained showed that the native species grew less with the water changes, mainly due to the lack of water, and the invasive species did not show strong growth alterations with the disturbances used. Furthermore, the species were shown to alter the growth variables in competition, impacting the native species more. On the other hand, the species in terms of temporal stability did not change growth and both may have advantages in impacted environments. Regarding the distribution of species, the results showed that the dispersion of the invasive exotic plant will be greater in areas that already have its presence, and also that this species may invade new places, such as Germany and Austria. In a future scenario of global climate change in 2070, this invasive species could occur in protected areas. Regarding the national territory, U. mutica will lose part of its distribution in Brazil, mainly in the north and northeast regions, including areas of protection and conservation. For P. dichotomiflorum, it is possible that it will lose a large part of its natural habitat in the two future scenarios, but it will increase its occurrence in other places, being able to become a potential invasive. Therefore, the results achieved indicate that both species have important characteristics in coping with climate change and show that the native species has an invasive behavior, with information of enormous value to environmental managers, especially in the management work of the two species of Poaceae, which have invasive potential for preserved areas, and in research that evidence areas susceptible to invasion.

Description: As mudanças climáticas globais tem como principal resultado o aumento na frequência e na severidade de eventos extremos, tais como períodos mais prolongados de seca, e mais dias quentes ao longo do ano, o que torna os eventos de seca ainda mais severos. Certas espécies vegetais possuem alto potencial invasor, que se deve à sua tolerância a condições adversas e à recuperação de seus indivíduos após algum distúrbio, o que aumenta a possibilidade de colonização e estabelecimento em novos ambientes, interferindo em comunidades nativas. Analisou-se experimentalmente o efeito da competição interespecífica da planta invasora Urochloa mutica com a espécie nativa Panicum dichotomiflorum, em seu estabelecimento, resistência e resiliência, simulando condições de eventos hídricos extremos e a distribuição de Panicum dichotomiflorum e Urochloa mutica, particularmente em áreas de proteção ambiental. Os resultados alcançados mostraram que a espécie nativa, cresceu menos com as mudanças hídricas, principalmente pela falta de água e a espécie invasora mostrou não sofrer fortes alterações de crescimento com os distúrbios empregados. As espécies mostraram alterar as variáveis de crescimento em competição, impactando de maior maneira a espécie nativa. Por outro lado, as espécies em termos de estabilidade temporal não alteraram o crescimento e ambas podem apresentar vantagens em ambientes impactados. Em relação à distribuição das espécies, os resultados mostraram que a dispersão da planta exótica invasora será maior em áreas que possuem sua presença, e também que essa espécie poderá invadir novos lugares, como Alemanha e Áustria. Em cenário futuro de mudança climática global em 2070, essa espécie invasora pode ocorrer em áreas protegidas. Com relação ao território nacional, U. mutica perderá parte da sua distribuição no Brasil, principalmente na região norte e nordeste, incluindo áreas de proteção e conservação. Para P. dichotomiflorum, é possível que perdera grande parte de seu habitat natural nos dois cenários futuros, mas aumentará sua ocorrência em outros lugares, podendo se tornar uma invasora em potencial. Portanto, os resultados alcançados indicam que ambas as espécies possuem características importantes no enfrentamento às mudanças climáticas e evidenciam que a espécie nativa apresenta comportamento invasor, com informações de enorme valia para gestores ambientais, especialmente nos trabalhos de manejo das duas espécies de Poaceae, que têm potencial invasor para áreas preservadas, e em pesquisas que evidenciem áreas suscetíveis a invasões.

Description: Masters

Description: The invasion success of non-native species depends on several factors, and native populations and biotic characteristics of non-native environments can offer resistance to non-native species development. Reservoirs can facilitate submerged macrophyte invasion once it modifies the environment and provides favorable abiotic conditions to macrophyte establishment and development. However, previous colonization of native species can resist the development of invasive ones through priority effects. In this investigation we used large data-set (1120 samplings during 4 years) obtained in the Itaipu Reservoir (Brazil/Paraguay) to assess the relationship between the abundance of the native submerged macrophyte Egeria najas and of the invasive Hydrilla verticillata and the water level, littoral slope and Secchi disk depth. We also investigated how the concomitant and previous abundance of both macrophytes correlates. A spatial-temporal modeling was applied using Integrated Nested Laplace Approximations method, which controls the effect of spatial-temporal autocorrelation. Our results indicate an important role of water transparency, littoral slope and water level oscillations (in terms of amplitude and increased hydrometric level), in a short period of time (30 days) for the temporal dynamics of the abundance of both species. However, alterations of the hydrometric levels and of the littoral slope affected H. verticillata to a greater extent than E. najas. In addition, the abundance of each species was related with its own abundance in previous samplings, highlighting the importance of vegetative propagule pressure and resistance structures for population recovery. The magnitude of the interaction between both species in concomitant occurrence in the same site was abundance dependent.

Description: O sucesso da invasão de espécies não nativas depende de vários fatores. Populações nativas e características bióticas de ambientes não nativos podem oferecer resistência ao desenvolvimento de espécies não nativas. Porém, a colonização prévia de espécies nativas pode impor resistência ao desenvolvimento de espécies invasoras por meio de efeitos de prioridade. Nesta investigação utilizou-se um grande conjunto de dados (1120 amostragens durante 4 anos) obtidos Reservatórios podem facilitar a invasão de macrófitas submersas, uma vez que modificam o ambiente e fornecem condições abióticas favoráveis para o estabelecimento e desenvolvimento de macrófitas no reservatório de Itaipu (Brasil/Paraguai) para avaliar a relação entre a abundância da macrófita submersa nativa Egeria najas e da invasora Hydrilla verticillata e o nível da água, declividade litorânea e profundidade do disco de Secchi. Também se investigou, como a abundância concomitante e prévia de ambas as macrófitas se correlaciona. Uma modelagem espaço-temporal foi aplicada usando o método de Aproximações Aninhadas Integradas de Laplace, que controla o efeito da autocorrelação espaço-temporal. Os resultados indicam um importante papel da transparência da água, declividade litorânea e oscilações do nível da água (em termos de amplitude e aumento do nível hidrométrico), em um curto período de tempo (30 dias) para a dinâmica temporal da abundância das duas espécies. Contudo, as alterações dos níveis hidrométricos e do declive litorâneo afetaram mais H. verticillata em comparação a E. najas. Ademais, a abundância de cada espécie foi relacionada com a sua própria abundância em amostragens anteriores, evidenciando a importância da pressão do propágulo vegetativo e das estruturas de resistência para a recuperação populacional. A magnitude da interação entre as duas espécies ao ocorrerem concomitantemente no mesmo ponto foi dependente da abundância.

Description: Masters

Description: Freshwater ecosystems such as the Upper Paraná River floodplain are constantly subjected to environmental changes caused by natural disturbances, but mainly by anthropogenic impacts (such as dams), which have drastically affected the biodiversity of these aquatic systems. One way to assess the rates of environmental change in systems such as plains is through biomonitoring studies on large temporal scales, with diatoms being excellent bioindicators in determining environmental changes in different aquatic ecosystems. Based on this, the temporal pattern of the periphytic diatom community of a lake in the upper Paraná River floodplain was investigated in order to seek patterns that reflect the environmental changes in this plain, covering studies with different approaches, such as ecology, taxonomic and of environmental education. As a result of these different studies, it is noteworthy that the association of the taxonomic and functional approach in the components of beta diversity was extremely important for the interpretation of variation in the composition of diatom species in a long time series, especially when considering the importance of the contribution beta diversity site - LCBD. It was also sought to highlight the use of diatoms as indicators in determining hydrological changes, reinforcing the need for continuous monitoring of the region, in order to follow the direction of ecological changes, both hydrological and climatic in this plain. The importance of taxonomic studies in the plain was also highlighted in this thesis, in order to better understand the local biodiversity of diatoms, since new species such as Staurosirella paranaensis are being registered. Finally, this thesis includes a proposal for educational games on microalgae and their ecological importance in the environmental indication of aquatic bodies, to emphasize the relevance of environmental education in the research, teaching and extension process.

Description: Ecossistemas de água doce como a planície de inundação do alto rio Paraná estão constantemente submetidos a mudanças ambientais causadas por distúrbios naturais, mas principalmente por impactos antrópicos (como barramentos), que tem afetado drasticamente a biodiversidade desses sistemas aquáticos. Uma forma de avaliar as taxas de alterações ambientais em sistemas como as planícies, é por meio dos estudos de biomonitoramento em grandes escalas temporais, sendo as diatomáceas excelentes bioindicadoras na determinação de mudanças ambientais nos diversos ecossistemas aquáticos. Com base nisso, foi investigado o padrão temporal da comunidade de diatomáceas perifíticas de um lago da planície de inundação do alto rio Paraná, a fim de buscar padrões que refletem as alterações ambientais desta planície, abrangendo estudos com diferentes abordagens, como ecologia, taxonômica e de educação ambiental. Como resultado destes diferentes estudos, ressalta-se que a associação da abordagem taxonômica e funcional nos componentes da diversidade beta foi de extrema importância para a interpretação de variação da composição de espécies de diatomáceas em uma longa série temporal, principalmente quando consideramos a importância da contribuição local da diversidade beta - LCBD. Também se buscou evidenciar o uso das diatomáceas como indicadores na determinação das alterações hidrológicas, reforçando a necessidade de um monitoramento contínuo da região, no intuito de acompanhar a direção das mudanças ecológicas, tanto hidrológicas quanto climáticas desta planície. A importância dos estudos taxonômicos na planície, também foi destaque nesta tese, a fim de conhecer melhor a biodiversidade local de diatomáceas, uma vez que novas espécies estão sendo registradas, como a Staurosirella paranaensis. Por fim, esta tese engloba uma proposta de jogos didáticos sobre microalgas e a importância ecológica delas na indicação ambiental de corpos aquáticos, no intuito de ressaltar a relevância da educação ambiental no processo de pesquisa, ensino e extensão.

Description: PhD

Description: The degree at which populations are correlated in space is called spatial synchrony and can be affected by interspecific interactions, dispersion, and large-scale environmental factors, i. e. Moran effect. The study of this phenomenon can help understanding the temporal stability of communities and the underlying mechanisms. The influence of damming in a river from the Amazon basin (Santo Antônio do Jari HPP) on the synchrony of the environment and the phytoplankton community was evaluated, both for the total density and for different Reynolds functional groups. Was investigated whether the effects would be similar for the main channel (Jari River), tributaries, and for the total area (Jari + tributaries). The mean synchrony values and the confidence intervals of each abiotic variable, functional group, and the total density were estimated for the total area, Jari River and tributaries. Matrix-based multiple regression were also performed to identify the most important drivers of synchrony of the phytoplankton. Changes in the synchrony patterns were verified after the damming. The temporal dynamics of environmental variables, total density and of some functional groups was more synchronous when considering only the Jari River, than the total area or only tributaries. Environmental synchrony and environmental distance were the main mechanisms behind synchrony for some functional groups.

Description: O grau de correlação de populações no espaço é denominado sincronia espacial e pode ser afetado por interações interespecíficas, dispersão e fatores ambientais de ampla escala, (i. e., efeito Moran). O estudo deste fenômeno pode colaborar na compreensão da estabilidade temporal das comunidades e a descobrir quais os mecanismos associados ao processo. Avaliou-se a influência de um barramento em um rio da bacia Amazônica (UHE Santo Antônio do Jari) sobre a sincronia espacial ambiental e do fitoplâncton do rio Jari e tributários. Mensurou-se a sincronia (total, média e intervalo de confiança) para cada variável abiótica, para a densidade de toda a comunidade e para cada grupo funcional de Reynolds, considerando a área total (11 locais - rio Jari + tributários), apenas rio Jari (cinco locais) e apenas tributários (seis locais), utilizando uma série temporal de oito anos. Regressões matriciais múltiplas foram utilizadas para identificar os fatores determinantes da sincronia do fitoplâncton. Verificou-se mudanças nos padrões de sincronia após o barramento. A dinâmica temporal das variáveis ambientais, da densidade de toda a comunidade e de alguns grupos funcionais apresentou-se mais sincrônica quando considerado somente o rio Jari, do que toda a área ou somente os tributários. Em geral, a distância ambiental mostrou-se o preditor mais importante para explicar a sincronia espacial do que a distância geográfica.

Description: Masters

Description: The survival and growth of fish larvae during ontogeny are related to the ability to obtain adequate food, providing subsidies for individuals reach the adult age. The foraging capacity, availability and abundance of prey and morphological development, especially swimming performance and visual acuity are important factors in reproductive success. In this study, the aspects related to feeding during the ontogeny of fish larvae from a floodplain system were analyzed, evaluating the coexistence capacity and the predator-prey interaction. Specifically, the objectives were (1) to analyze the inter and intraspecific variations in the diet of three invasive fish species (Auchenipterus osteomystax, Plagioscion squamosissimus and Hypophthalmus oremaculatus) during their initial ontogeny and the relationship with coexistence; and (2) to apply a new approach in trophic ecology studies during ontogeny, evaluating the interaction and organization of the predator-prey network, using A. osteomystax as model. The larvae of invasive fish species had different diets inter and intraspecifically, low diet overlap and high niche breadth primarily for P. squamosissimus. The coexistence of larvae of these species is probably possible due to low competition, differentiation of trophic guilds, resource partitioning and trophic plasticity. Regarding the predator-prey network, A. osteomystax showed a nested structure, low connectivity and a pattern of segregation in resource consumption. The larvae fed exclusively on aquatic insects, impacting the robustness of the network when the most frequent prey in the diet is removed, here represented by Diptera and Chironomidae pupa. Furthermore, the correlation between metric variables and morphological networks showed that the species is of more general position as the network develops, increasing its capacity predation. Both studies demonstrated the importance of knowing the species-habitat interaction and the processes that govern prey capture, avoiding inter and intraspecific competition through resource partitioning and behavioral and foraging changes during ontogeny.

Description: A sobrevivência e o crescimento das larvas de peixes durante a ontogenia estão relacionados com a capacidade de se obter alimento adequado, o qual fornece subsídios para que os indivíduos alcancem a vida adulta. A capacidade de forrageamento, a disponibilidade e abundância de presas e o desenvolvimento morfológico, principalmente da capacidade natatória e acuidade visual são fatores preponderantes no sucesso reprodutivo. Analisou-se, os aspectos relacionados à alimentação durante a ontogenia das larvas de peixes de um sistema de planície de inundação, avaliando a capacidade de coexistência e a interação predador-presa. Especificamente os objetivos foram (1) analisar as variações inter e intraespecíficas da dieta de três espécies de peixes invasoras (Auchenipterus osteomystax, Plagioscion squamosissimus e Hypophthalmus oremaculatus) durante a sua ontogenia inicial e a relação com a coexistência; (2) aplicar uma nova abordagem em estudos de ecologia trófica durante a ontogenia, avaliando a interação e organização da rede predador-presa, usando como modelo A. osteomystax. As larvas apresentaram dietas distintas tanto inter, quanto intraespecificamente, baixa sobreposição alimentar a alta amplitude de nicho principalmente para P. squamosissimus. A coexistência das larvas destas espécies é possível provavelmente devido à baixa competição, diferenciação de guildas tróficas, particionamento de recursos e plasticidade trófica. Em relação à rede predador-presa, A. osteomystax apresentou estrutura aninhada, baixa conectância e um padrão de segregação no consumo de recursos. As larvas desta espécie alimentaram-se exclusivamente de insetos aquáticos, com impacto na robustez da rede quando ocorre a remoção de presas mais frequentes na dieta, aqui representada por pupa de Diptera e Chironomidae. A correlação entre variáveis morfológicas e as métricas de redes mostrou que a espécie assume uma posição mais generalista na rede conforme ocorre seu desenvolvimento, aumentando sua capacidade de predação. Ambos os estudos demonstraram a importância de se conhecer a interação espécie-habitat e os processos que regem a captura de presas, evitando a competição inter e intraespecífica através do particionamento de recursos e mudanças comportamentais e de forrageamento durante a ontogenia.

Description: PhD

Description: Die Ausgabe der Geowissenschaftlichen Mitteilungen vom März 2022 enthält die Themenblöcke: GEOfokus: (Archäometrie in Deutschland), GEOaktiv (Wirtschaft, Beruf, Forschung und Lehre), GEOlobby (Gesellschaften, Verbände, Institutionen), GEOreport (Geowissenschaftliche Öffentlichkeitsarbeit, Tagungsberichte, Ausstellungen, Exkursionen, Publikationen), GEOszene (Würdigungen, Nachrufe).

Description: DFG, SUB Göttingen

Description: journal

Description: Die Ausgabe der Geowissenschaftlichen Mitteilungen vom März 2022 enthält die Themenblöcke: GEOfokus: Die marine Seismik der Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), GEOaktiv (Wirtschaft, Beruf, Forschung und Lehre), GEOlobby (Gesellschaften, Verbände, Institutionen), GEOreport (Geowissenschaftliche Öffentlichkeitsarbeit, Tagungsberichte, Ausstellungen, Exkursionen, Publikationen), GEOszene (Würdigungen, Nachrufe).

Description: DFG, SUB Göttingen

Description: journal

Description: Evaluating patterns and predictors of species distribution is important, because anthropogenic actions have been threatening global biodiversity. Hence, researchers have used measures of beta-diversity, defined as the variation in species composition amongst sites of a given area. Several measures of beta-diversity have been created, because using this approach makes it simple to elaborate and test ecological hypotheses, considering species distribution. Here, it was aimed to contribute to the knowledge about drivers and patterns of distribution amongst aquatic communities in Neotropical riverine floodplains. For this, this thesis was fractionated into two approaches, in which was used two different methods to measure beta-diversity. In the first approach, it was assessed the environmental and spatial factors affecting the beta-diversity facets (species-, traits- and phylogeny-based), and their components (Beta-total, replacement and richness difference), of ostracod communities associated with macrophytes, in the Upper Paraná River floodplain. Furthermore, it was compared these factors amongst the different life forms: emergent, rooted floating, rooted submerged, free submerged and free floating. In the second approach, it was used the local contribution to beta-diversity approach (LCBD) to evaluate the drivers and patterns of ecological uniqueness of the sites, in terms of species composition, in four floodplain systems, Amazon, Araguaia, Pantanal and Paraná. It was gathered data on community composition for eight aquatic biological groups: phytoplankton, ciliates, testate amoebae, rotifers, cladocerans, copepods, ostracods and fish. In general, environmental filtering was more important in explaining distribution patterns of communities, and the species sorting mechanism might be responsible for them, within and amongst the floodplains. In the first approach, different environmental and spatial factors influenced each of the beta-diversity facets of ostracod communities (species-, traits- and phylogeny-based). The factors affecting ostracod beta-diversity were different amongst the macrophyte life forms, evidencing the importance of considering them in ecological surveys of associated communities. In the second approach, the Amazon and Paraná floodplains had higher uniqueness in terms of species composition, showing the importance of conservation actions in these ecosystems. Furthermore, the drivers (e.g. environmental variables) and patterns of LCBD were different amongst the different biological groups, evidencing the need to include a variety of taxa. It was considered that the results of this thesis, based on beta-diversity analyses, contributed to a better understanding of drivers and patterns of distribution amongst communities in Neotropical floodplains. This is because researchers can use them as a reference in conservation and restoration plans for these systems and to prevent the destruction of areas with high conservation value, for example, by the construction of dams and reservoirs.

Description: Avaliar os padrões e preditores da distribuição de espécies é importante, visto que as ações antrópicas têm ameaçado a biodiversidade global. Para isso, pesquisadores têm usado medidas de diversidade-beta, definida como a variação na composição de espécies entre os locais de uma determinada área. Várias medidas de diversidade-beta têm sido produzidas, visto que através desta abordagem tem sido simples elaborar e testar hipóteses ecológicas, considerando a distribuição de espécies. O objetivo desta tese foi contribuir para o conhecimento de padrões e preditores da distribuição de comunidades aquáticas de planícies de inundação Neotropicais. Assim, foi fracionada em duas abordagens, onde foram utilizados dois métodos diferentes de medida de diversidade-beta. Na primeira abordagem, foi avaliado os fatores ambientais e espaciais que afetam as facetas da diversidade-beta (baseado nas espécies, traços e filogenia) e seus componentes (beta-total, replacement e richness difference), das comunidades de ostrácodes associados a diferentes formas de vida de macrófitas aquáticas, na planície de inundação do alto rio Paraná. Esses fatores foram comparados entre as diferentes formas de vida: emergentes, submersas e flutuantes enraizadas e submersas e flutuantes livres. Na segunda abordagem, foi utilizada a análise da contribuição local para a diversidade-beta (LCBD) para avaliar os preditores e padrões da singularidade dos locais, considerando a composição de espécies, em quatro planícies de inundação, Amazonas, Araguaia, Pantanal e Paraná. Para isso, foram analisados oito grupos biológicos aquáticos: fitoplâncton, ciliados, amebas testáceas, rotíferos, cladóceros, copépodes, ostrácodes e peixes. Em geral, os filtros ambientais foram mais importantes para explicar os padrões de distribuição das comunidades, e o mecanismo species sorting pode ser responsável por tais padrões, dentro e entre as planícies de inundação. Na primeira abordagem, diferentes fatores ambientais e espaciais influenciaram cada uma das facetas da diversidade-beta de ostrácodes (baseadas nas espécies, traços e filogenia). Ademais, os fatores que afetaram a diversidade-beta de ostrácodes foram diferentes entre as formas de vida das macrófitas aquáticas, evidenciando a necessidade de considerá-las em estudos ecológicos considerando as comunidades associadas. Na segunda abordagem, as planícies de inundação do Amazonas e Paraná foram as mais singulares em termos de composição de espécies, que avaliam a importância da preservação destes ecossistemas. Os padrões e preditores (variáveis ambientais) da LCBD foram diferentes entre os grupos biológicos, confirmando a importância de incluir diferentes taxa. Os resultados desta tese, baseados em análises de diversidade-beta, contribuíram para um melhor entendimento sobre os padrões e preditores da distribuição de comunidades aquáticas de planícies de inundação Neotropicais. Dessa forma, eles podem ser usados por pesquisadores como referência para planos de restauração e conservação destes ecossistemas, assim como evitar que áreas de grande valor de conservação sejam impactadas, por exemplo, pela construção de reservatórios e hidroelétricas.

Description: PhD

Description: Aquatic ecosystems are especially vulnerable to species invasion due to their extent, diversity of habitats, and inherent dynamics. Invasive aquatic macrophytes are of great concern because of their great influence on aquatic ecosystems. In this thesis, we sought to contribute to the field of biological invasions of aquatic macrophytes at regional and global levels using knowledge pertinent to monitoring and preventing the introduction of species. Given that, one of the most concerning invasive species in the world, Hydrilla verticillata (L.f.) Royle, was evaluated in different types of environments in a subtropical floodplain. The relationship of occurrences of this species with its main abiotic predictors was investigated, as well as its relationship with the native (equivalent) species Egeria najas Planch. right after its detection and 10 years later. This work contributed with insights regarding the biotic interactions of invaders and natives as well as changes in environmental predictors that highlight anthropogenic impacts that deserve attention. A second work was carried out to leverage knowledge about invasive aquatic macrophytes at a global level. A compilation of data from several available sources was carried regarding the most common pathways of introduction of aquatic macrophytes to identify the regions of origin and destination of these species and their respective functional groups. Such information is crucial for the determination of public policies and management strategies to avoid the introduction of unwanted species. In summary, this thesis helps the characterization of aquatic macrophyte invasions aiming at their prevention.

Description: Os ecossistemas aquáticos são especialmente vulneráveis à invasão de espécies devido a sua grande extensão, diversidade de habitat e a dinâmica inerente destes habitat. Macrófitas aquáticas invasoras geram muita preocupação devido à sua grande influência nos ecossistemas aquáticos. Buscou-se contribuir para o campo das invasões biológicas de macrófitas aquáticas em nível regional e global com conhecimentos pertinentes ao monitoramento e prevenção de espécies introduzidas. Na primeira abordagem avaliou-se a invasão de uma das espécies de macrófitas invasoras mais preocupantes do mundo, Hydrilla verticillata (L.f.) Royle, em diferentes tipos de ambientes de uma planície subtropical. Investigou-se a relação das ocorrências desta espécie com seus principais preditores abióticos, bem como sua relação com a espécie nativa (morfologicamente semelhante) Egeria najas Planch. nos primeiros anos de sua introdução e 10 anos depois. Tal trabalho destacou as interações bióticas entre a espécie invasora e a nativa bem como mudanças nos preditores ambientais que sugerem impactos antrópicos merecedores de atenção. Uma segunda abordagem foi realizada com o intuito de alavancar o conhecimento sobre macrófitas aquáticas invasoras em um nível global. Foi realizada uma compilação de dados acerca das vias e caminhos de introdução das macrófitas aquáticas a fim de identificar as regiões de origem e destino destas espécies e de seus respectivos grupos funcionais. Tais informações são cruciais para a determinação de políticas públicas e estratégias de manejo para evitar a introdução de espécies indesejadas. Em suma, os resultados das duas abordagens dão suporte a caracterização das invasões de macrófitas aquáticas visando sua prevenção.

Description: PhD

Description: Biological communities derive not from a random distribution of organisms but are the result of many processes that include abiotic factors, biotic interactions, and dispersion. The impact of human activities has affected the structure and functioning of ecological communities at an accelerated pace. The phytoplankton community represents a major primary producer of aquatic environments, therefore factors that interfere with its structure and dynamics can also impact other trophic levels in the ecosystem. In this perspective, functional redundancy was the central theme of the first paper, whose aim was to investigate the response of redundancy in phytoplankton communities to environmental factors, when measured for functional groups and functional traits. For this, six years of data collected quarterly (2008 to 2013) from two temperate and three subtropical lakes were used. Traits and groups were efficient to measure this attribute, however, the traits were more efficient when the structuring process of the communities was the environmental filtering. The functional traits most effectively explain the relationship between redundancy and environment. In the second paper, the influence of hydrodynamics, landscape and resources on the structure of the phytoplankton community during a floodplain lake restoration process was evaluated. As expected, factors related to hydrodynamics and resources (light and nutrients) were determinants for biovolume and density. The relative importance of landscape to community attributes increased over time of restoration. Cyanobacteria were dominant at the beginning of the restoration process, followed by phytoflagellates and diatoms. Aiming to disseminate science, the third article presents basic concepts of phytoplankton ecology and the main results related to the themes of the two scientific papers. In summary, the functional approach in phytoplankton ecology stands out as an important tool for the development of community ecology and for restoration and management of aquatic ecosystems projects.

Description: Comunidades biológicas não são combinações aleatórias de espécies e sim o resultado de diversos processos que incluem fatores abióticos, interações bióticas e dispersão. As ações antrópicas têm afetado a estrutura e funcionamento das comunidades ecológicas em ritmo acelerado. A comunidade fitoplanctônica representa o principal produtor primário dos ambientes aquáticos, portanto fatores que interferem na sua estrutura e dinâmica, também podem causar impactos nos demais níveis tróficos do ecossistema. Nessa perspectiva, a redundância funcional foi tema central da primeira abordagem, cujo objetivo foi investigar a resposta da redundância de comunidades fitoplanctônicas, diante de fatores ambientais, quando medida para grupos e traços funcionais. Para isso utilizou-se seis anos de dados coletados trimestralmente (2008 a 2013) referentes a dois lagos temperados e três subtropicais. Traços e grupos foram eficientes para medir esse atributo, entretanto os traços foram mais eficientes quando o processo estruturador das comunidades foi a filtragem ambiental. Os traços funcionais do fitoplâncton explicaram de maneira mais eficaz a relação entre redundância e ambiente. Na segunda abordagem, avaliou-se a influência da hidrodinâmica, paisagem e recursos sob a estrutura da comunidade fitoplanctônica durante um processo de restauração de um lago de planície de inundação. Como esperado, os fatores relacionados a hidrodinâmica e aos recursos (luz e nutrientes) foram determinantes para o biovolume e densidade. A importância relativa da paisagem para os atributos da comunidade aumentou ao longo do tempo de restauração. Cianobactérias foram dominantes no início da restauração, seguidas de fitoflagelados e diatomáceas. Com o objetivo de divulgar a ciência, a terceira abordagem apresenta conceitos básicos do fitoplâncton e agrupa os principais resultados referentes a redundância funcional e restauração lacustre. Enfatiza-se o uso de traços e grupos funcionais do fitoplâncton como uma importante ferramenta para o desenvolvimento da ecologia de comunidades e para projetos de restauração e manejo dos ecossistemas aquáticos.

Description: PhD

Description: The aquatic communities in phytotelmata are structured by several environmental factors, and they act in the trophic and non-trophic interactions of these environments. Phytotelmata are micro-ecosystems of fresh water, rich in species and are considered an excellent study model. Here, we use plants from the family Bromeliaceae of the species Quesnelia arvensis, to investigate the relationships between biotic and abiotic variables and their effects on interactions in phytotelmata. Our hypothesis was that habitat size and canopy cover gradients would determine the abundance of microbiota communities and their interactions. We carried out samples on bromeliads located in the state park of the Parque Estadual da Ilha do Cardoso - SP, Brazil, in different canopy cover gradients, in addition we selected plants of different sizes, to investigate the effects of habitat size. To check the interactions between the variables and score the interactions (positive and negative) we use the lasso graphical method, which exemplifies these interactions through a network graph. Also, we performed a simple regression analysis in to determine the correlations between biotic and abiotic variables. Our results indicate that the canopy cover and the size of the habitat (water volume) were the most important variables in interactions in phytothelmata. The canopy cover presented the greatest amount of negative connections, mainly with the levels of ammonia, Culicidae larvae and algae in general, with the exception of phyto-flagellates. In contrast, habitat size showed strong positive connections with rotifers and copepods and did not show any negative connection with other variables. Finally, our results demonstrate that among the set of factors analyzed, canopy cover and habitat size were in fact the most representative, as expected.

Description: As comunidades aquáticas em fitotelmatas são estruturadas por vários fatores ambientais que atuam nas interações tróficas e não tróficas desses ambientes. Fitotelmatas são microecossistemas de água doce, ricos em biodiversidade e são considerados um excelente modelo de estudo. Foram utilizadas plantas da família Bromeliaceae da espécie Quesnelia arvensis, com o objetivo de investigar as relações entre as variáveis bióticas e abióticas e seus efeitos sobre as interações da microbiota desses ambientes. A hipótese testada foi de que o tamanho do habitat e os gradientes de cobertura de dossel determinariam a abundância das comunidades da microbiota e suas interações. Foram realizadas coletas em bromélias localizadas no Parque Estadual da Ilha do Cardoso – SP, Brasil, em diferentes gradientes de cobertura de dossel e tamanhos, a fim de investigar os efeitos do tamanho do habitat. Para verificar as interações entre as variáveis e pontuar as interações (positivas e negativas) foi utilizado o método graphical lasso, que exemplifica essas interações através de um gráfico de rede. Também, foi realizada uma análise de regressão simples a fim de determinar as correlações entre as variáveis bióticas e abióticas. Os resultados encontrados apontam que a cobertura de dossel e o tamanho do habitat foram as variáveis mais importantes nas interações em fitotelmatas. A cobertura de dossel apresentou a maior quantidade de conexões negativas, principalmente com os níveis de amônia, larvas de Culicídeos e algas em geral, com exceção dos fitoflagelados. Em contrapartida, o tamanho do habitat apresentou fortes conexões positivas com os rotíferos e os copépodes e não apresentou nenhuma conexão negativa com outras variáveis. Por fim, corroborando nossa hipótese, os resultados desse estudo demonstram que, dentre o conjunto de fatores analisados, a cobertura de dossel e o tamanho do habitat foram os mais representativos para a estruturação trófica das comunidades da microbiota assim como esperado.

Description: Masters

Description: Freshwater environments are the most vulnerable to climate change, and projected increases in temperature over the coming decades bring an unfavorable scenario for aquatic organisms. Warming, when combined with nutrient availability, can trigger even more complex interactions in the functioning of microbial food webs. The aim of this study was to evaluate the influence of warming and resource availability from detritus on the community structure of freshwater aquatic microbiota (richness, density and beta diversity) using natural microcosms (tank bromeliads) as a model system. Warming was simulated with temperature increase projections for the next decades following the Intergovernmental Panel on Climate Change. The dry mass (g) of coarse particulate organic matter (CPOM) from each bromeliad was used as a measure for resource availability (detritus biomass). Detritus biomass caused a negative effect on algal and microfauna density, and for total algal richness. Detritus biomass explained the variation for almost all components of microfauna beta diversity, except for the replacement component (βrepl), where warming was responsible for this variation. For algae the interaction between warming and detritus biomass was most important in explaining the variation in total beta and βrepl, while for the richness difference component (βrich) this variation was explained only by detritus biomass. In summary, the results obtained suggest that warming and increased detritus biomass acted strongly on the structuring of the communities, reducing the density and richness of the aquatic microbiota. Furthermore, the results provide evidence that temperature can increase the dissimilarity of communities of groups of organisms in the heterotrophic plot (microfauna), mainly by species substitution.

Description: Os ambientes de água doce são os mais vulneráveis às alterações climáticas e, as projeções de aumento da temperatura para as próximas décadas, trazem um cenário desfavorável para organismos aquáticos. O aquecimento, quando combinado com disponibilidade de nutrientes, pode desencadear interações ainda mais complexas no funcionamento das teias alimentares microbianas. O objetivo deste estudo foi avaliar a influência do aquecimento e da disponibilidade de recursos proveniente de detritos na estrutura das comunidades da microbiota aquática de água doce (riqueza, densidade e diversidade beta), usando microcosmos naturais (bromélias-tanque) como sistema modelo. O aquecimento foi simulado com as projeções de aumento da temperatura para as próximas décadas seguindo o Painel Intergovernamental sobre Mudanças Climáticas. A massa seca (g) de matéria orgânica particulada grosseira (CPOM) de cada bromélia foi usada como medida para a disponibilidade de recurso (biomassa de detritos). A biomassa de detritos causou efeito negativo sobre a densidade de algas e da microfauna, e para a riqueza total de algas. A biomassa de detritos explicou a variação para quase todos os componentes da diversidade beta da microfauna, exceto para o componente replacement (βrepl), em que o aquecimento foi responsável por essa variação. Para as algas a interação entre aquecimento e biomassa de detritos foi o mais importante para explicar a variação da beta total e βrepl, enquanto que para o componente de diferença de riqueza (βrich) essa variação foi explicada apenas pela biomassa de detritos. Em síntese, os resultados obtidos indicam que o aquecimento e o aumento da biomassa de detritos atuaram fortemente na estruturação das comunidades, reduzindo a densidade e a riqueza da microbiota aquática. Outrossim, os resultados trazem evidências de que a temperatura pode aumentar a dissimilaridade das comunidades de grupos de organismos da parcela heterotrófica (microfauna), principalmente por substituição de espécies.

Description: Masters

Description: Since the classic Forbes publication “The Lake as a Microcosm” in 1887, scientific research on freshwater ecosystems has been boosted due to the formulation of the first limnological concepts. For a long period, scientific research aimed at the spatial distribution of communities was focused on large water bodies, leaving aside studies in small freshwater environments, such as bromeliad phytotelmata. The first work of this thesis carried out a scientometric analysis in virtual databases on bromeliad phytotelmata, and 140 publications were found. South America was the region with the highest number of articles published. Most articles presented predictive designs, focusing on community ecology. Insecta was the most recorded group of organisms. In the second article, it was investigated how the microcrustacean community (composition, abundance and richness) is associated with the phytotelmata of Nidularium innocentii Lem. was influenced by the limnological variables present along the altitudinal gradient. The study was carried out in Serra da Prata, in the state of Paraná. The results did not show a distribution pattern in species richness along the altitudinal gradient, refuting the central domain effect hypothesis among others. However, there were dissimilarities in the composition of microcrustacean species in relation to altitudes. The different climatic types and vegetation types directly influenced the environmental variables in the phytotelmata microcosms, leading to similarities in species composition between altimetric elevations located in the same climatic region and dissimilarities between different climates.

Description: Desde a clássica publicação de Forbes “The Lake as a Microcosmo”, em 1887, pesquisas científicas em ecossistemas dulcícolas foram impulsionadas devido à formulação dos primeiros conceitos limnológicos. Durante um longo período, pesquisas científicas direcionadas à distribuição espacial de comunidades foram voltadas aos grandes corpos hídricos, deixando de lado estudos em pequenos ambientes de água doce, como fitotelmata de bromeliáceas. Realizou-se uma análise cienciométrica em bases de dados virtuais sobre fitotelmata de bromeliáceas, sendo encontradas 140 publicações. A América do Sul foi a região com maior número de artigos publicados. A maioria dos artigos apresentou delineamentos preditivos, com enfoque sobre ecologia de comunidades. Insecta foi o grupo de organismos mais registrado. Investigou-se como a comunidade de microcrustáceos (composição, abundância e riqueza), associada à fitotelmata de Nidularium innocentii Lem. foi influenciada pelas variáveis limnológicas presentes ao longo do gradiente altitudinal. O estudo foi realizado na Serra da Prata, no estado do Paraná. Os resultados não apresentaram um padrão de distribuição na riqueza de espécies ao longo do gradiente altitudinal, refutando a hipótese do efeito do domínio central dentre outras. Contudo, ocorreram dissimilaridades na composição de espécies de microcrustáceos em relação às altitudes. Os diferentes tipos climáticos e de vegetações influenciaram diretamente as variáveis ambientais nos microcosmos de fitotelmata, levando à similaridades na composição de espécies entre cotas altimétricas localizadas na mesma região climática e dissimilaridades entre climas distintos.

Description: PhD

Description: Ecological studies in all environments of the world the effects of non-native species in various parts of the world are discussed. Regarding the invasion of these environments, we highlight the Phylum Sanitary, especially the ecological Mollusa, for presenting numerous gastronomic classes, with many species with potential, which can lead to as many sanitary, as well as sanitary and graves, in places of invasion. Know the invasive species that are reported in their scientific distribution, in this case introduction and the main ones are reported, is of fundamental importance. Knowing the risk of introducing an invasive species, and its impacts on the invaded places, it is necessary to find ways of prevention. A precious tool of meaning is an invasion of the invasive potential of one, thus generating a risk that indicates the suitability of the habitat or probability of occurrence based on the environmental conditions of the native area and the area in which the species may become invasive. . In this way, the adequacy of the invasive Melanoides tuberculata against a native species by Biomphalaria glabra, which is also a species with potential to cause toilets, is of fundamental importance, to predict possible invasion sites, and if the species are competing for the same ecological niches. Thus, the present work is subdivided into two works that address issues such as: a systematic of scientific articles about invasive freshwater gastropods. The second work will address the modeling of the current and future potential distribution of two problematic gastropod species in South America.

Description: Estudos ecológicos em ambientes aquáticos continentais têm discutido com amplitude o efeito das espécies não nativas em várias partes do mundo. Em relação à invasão destes ambientes, destacamos o Filo Mollusca, principalmente a classe Gastropoda, por apresentar inúmeras espécies, sendo muitas destas espécies com potencial invasor, que podem levar a prejuízos tanto ecológicos, quanto econômicos e sanitários graves, em locais de invasão. Neste caso, conhecer as principais espécies invasoras que são reportadas em artigos científicos, entender sua distribuição global, seus meios de introdução e os principais danos causados, é de fundamental importância. Sabendo do risco de introdução de uma espécie invasora, e seus impactos nos locais invadidos, faz-se necessário estudos de formas de prevenção. Uma ferramenta valiosa nesse sentido é a inferência do potencial invasor de uma espécie, gerando assim um mapa de risco que indique a adequabilidade do habitat ou probabilidade de ocorrência com base nas condições ambientais da área nativa e da área em que a espécie pode vir a se tornar invasora. Deste modo, verificar adequabilidade da espécie invasora Melanoides tuberculata frente a uma espécie nativa Biomphalaria glabrata, que também é uma espécie com potencial causador de prejuízos sanitários, é de fundamental importância, para prevermos os possíveis locais de invasão, e se as espécies estão competindo pelos mesmos nichos ecológicos. Deste modo, foi efetuado uma revisão sistemática de artigos científicos a respeito de gastrópodes invasores de água doce. Em um segundo momento foi efetuado uma modelagem da distribuição potencial atual e futura de duas espécies de gastrópodes problemáticas na América do Sul.

Description: PhD

Description: Global warming can affect thedistribution and development of organisms indirectly through changes in climate patterns and thus, in the habitat of species and, directly through the influence of high temperatures on the physiological and morphological development of organisms. These changes in thepatterns of species density, feeding and reproduction driven by warming and environmental changes also induce changes in the ecological relationships in which these organisms are involved. Thus, we investigated how these two effects of global warming, affect the performance, distribution and ecological relationships of zooplankton species, using functional responses of the organisms, such as biomass production and functional traits, in order to link these changes in zooplankton with ecosystem services. This studyis divided into three approaches, microcosm experiments controlling three temperatures, predation and competition and, a spatial and temporal approach in the upper Paraná River floodplain. In our experiments, we observed that temperature increases indeed lead to more complex relationships inside food webs, with possible negative consequences for aquatic ecosystems. However, the temperature was not the predominant factor in determining the performance of subtropical and temperate cladoceran species, as predation was the mainly structuring factor, changing the performance and competition among species. The study with the spatial and temporal approach showed that extreme climate events modify the limnological heterogeneity of shallow lakes, consequentlyaltering zooplankton species and functional traits, especially by species and traits substitution among environments (beta replacement). Factors related to predation, food availability, limnological variables and, temporal variations influenced differently the zooplankton functional beta diversity depending on the climatic event and the type of lake (connected or isolated), but limnological variables are in fact the most important factor in structuring the zooplankton distribution. Both warming and changes in climate patterns (especially intense dry seasons) negatively affected zooplankton organisms, reducing biomass production, secondary production and, the richness of functional traits among environments. The reduction of these zooplankton functional variables has negative consequences for energy stocks and, the flow of matter inside aquatic food webs, changing the ecosystem services.

Description: O aquecimento global pode afetar a distribuição e o desenvolvimento dos organismos indiretamente através das mudanças nos padrões climáticos e, assim, no habitat das espécies, e diretamente através da influência das altas temperaturas sobre o desenvolvimento fisiológico e morfológico dos organismos. Essas mudanças nos padrões de densidade, alimentação e reprodução das espécies conduzidas pelo aquecimento e mudanças ambientais induzem também alterações nas relações ecológicas em que esses organismos estão envolvidos. Desta maneira, tivemos como objetivo investigar como esses dois efeitos do aquecimento global, afetam a performance, a distribuição e as relações ecológicas das espécies zooplanctônicas, utilizando respostas funcionais dos organismos, como a produção de biomassa e traços funcionais, com o intuito de conectar essas alterações no zooplâncton com os serviços ecossistêmicos. Para responder a este objetivo, foram realizados experimentos em microcosmos controlando três temperaturas, predação e competição; e trabalho de campo com uma abordagem espacial e temporal na planície de inundação do alto rio Paraná. Nos experimentos observou-se que o aumento de temperatura de fato leva a relações mais complexas dentro das cadeias alimentares com possíveis consequências negativas para os ecossistemas aquáticos. Porém, a temperatura não foi o fator predominante em determinar a performance das espécies de cladóceros de climas temperado e subtropical, sendo que a predação foi o fator estruturante, alterando a performance e as relações de competição entre as espécies. Por meio da abordagem espacial e temporal, observou-se que os eventos climáticos extremos alteram a heterogeneidade limnológica dos lagos rasos com consequente alteração das espécies e dos traços funcionais do zooplâncton, especialmente por meio da substituição de espécies e traços entre os ambientes (beta replacement). Os fatores relacionados a predação, disponibilidade de alimento, variáveis limnológicas e as variações temporais influenciaram diferentemente a diversidade beta funcional do zooplâncton dependendo do evento climático e do tipo de lagoa (conectada ou isolada), mas,de fato as variáveis limnológicas foram o fator mais importante em estruturar a distribuição do zooplâncton. Tanto o aquecimento quanto as mudanças nos padrões climáticos (especialmente períodos de secas intensas) afetaram negativamente os organismos zooplanctônicos, com redução na produção de biomassa, na produção secundária, e na riqueza de traços funcionais entre os ambientes. A redução dessas variáveis funcionais do zooplâncton tem consequências negativas para os estoques de energia e para o fluxo de matéria dentro das cadeias alimentares aquáticas, com alterações nos serviços ecossistêmicos.

Description: PhD

Description: Reservoirs shores are usually colonized by submerged macrophytes, which have a high influence over the functional diversity of fish assemblages. However, there are also intense anthropogenic activities in these habitats, which may affect the functional structure of fish communities as well. Thus, aiming to evaluate the influence of anthropogenic activities and habitat complexity, provided by submerged macrophytes, on the functional diversity of the ichthyofauna of reservoirs, sampling was carried out in three sites in the marginal areas of the Itaipu reservoir, in places near and apart artificial beaches, with and without submerged macrophytes. Functional traits used were morphometric measurements taken from the sampled individuals (intraspecific traits), which were used to calculate three functional diversity indexes: functional richness, evenness and divergence. In general, we found no patterns in functional diversity indexes regarding the distance from artificial beaches (among sampling stations). In contrast, habitat complexity influenced the functional diversity of fish assemblages, which presented different results depending on macrophytes density. While functional richness increased in higher complexities, the opposite occurred considering functional evenness. Additionally, functional divergence was higher in regions without macrophytes. In conclusion, this study improves the knowledge on the importance of different habitats in the maintenance of the functional diversity of fishes in habitats of reservoirs shores, supporting the implementation of management and conservation strategies in these environments.

Description: Regiões litorâneas de reservatórios são normalmente colonizadas por bancos de macrófitas submersas, que possuem elevada influência sobre a diversidade funcional das assembleias aquáticas, inclusive peixes. Apesar disso, esses habitats apresentam alta influência antropogênica, o que também pode afetar a estruturação funcional de comunidades aquáticas. Portanto, para avaliar a influência das atividades antropogênicas e da complexidade de habitat, proporcionada pelas macrófitas, sobre a diversidade funcional da ictiofauna, foram amostrados três braços do reservatório de Itaipu, em regiões de praias artificiais e em locais afastados destas áreas (não praia), considerando a presença e ausência de macrófitas submersas. Traços funcionais derivados de variáveis morfométricas foram usados para o cálculo dos índices de riqueza, equitabilidade e divergência funcional, que incorporaram a variação intraespecífica das assembleias amostradas. Em geral, não houveram diferenças nos índices de diversidade funcional em função da proximidade de praias artificiais. Em contraste, a complexidade de habitat influenciou a diversidade funcional da ictiofauna e as respostas dos índices dependeram da densidade de macrófitas. Enquanto a riqueza funcional aumentou em maiores complexidades, foi observado o inverso em relação a equitabilidade funcional. Por fim, a divergência funcional foi maior em regiões de margem, sem macrófitas submersas. Por meio dos padrões identificados, esse trabalho contribui com o conhecimento sobre a importância dos diferentes habitats para a diversificação funcional das espécies de peixes em regiões litorâneas nos braços de reservatórios, com estrutura decorrente de macrófitas submersas, servindo como base para implementação de estratégias de manejo e conservação nestes ambientes.

Description: Masters

Description: In the study it was verified if the habitat complexity, assessed through macrophyte biomass, can mediate the interaction between fish and invertebrates, and help to explain the coexistence of congeneric species. Fish and invertebrates were sampled in ten macrophytes stand with different biomasses in upper Paraná River floodplain. The abundance and richness of invertebrates, the diet and the niche breadth of Moenkhausia bonita and Moenkhausia forestii were evaluated, as well as the overlap of the diet between the congeneric species. With the increase in macrophyte biomass, there was an increase in the abundance of invertebrates, however, the richness did not show a significant influence from the biomass. The diet of both species differed between macrophytes stands with different biomasses, the main difference being the decrease in invertebrate consumption, mainly aquatic, and the increase in consumption of plants. In addition, the consumption of the items proved to be dependent on their profitability and accessibility in the environment. The niche breadth of both species increased with the increase in macrophyte biomass, but there was no overlap of the niche between them. The results showed that although there was an increase in the invertebrate abundance, there was a decrease in the consumption of this resource, indicating that more complex stands can be more effective refuges for aquatic invertebrates. These results reveal the role of habitat complexity in mediating the interaction between fish and invertebrates, promoting coexistence between them, which helps to explain also the coexistence of ecologically similar fish species.

Description: Neste estudo verificou-se se a complexidade do habitat, avaliada por meio da biomassa de macrófitas, pode mediar a interação entre peixes e invertebrados, e ajudar a explicar a coexistência de espécies congêneres. Peixes e invertebrados foram amostrados em dez bancos de macrófitas com diferentes biomassas na planície de inundação do alto rio Paraná. Foram avaliadas a abundância e a riqueza de invertebrados, a dieta e a amplitude do nicho de Moenkhausia bonita e de Moenkhausia forestii, assim como a sobreposição da dieta entre as espécies. Com o incremento da biomassa de macrófitas houve uma ampliação na abundância de invertebrados, porém a riqueza não mostrou uma relação significativa com a biomassa. A dieta de ambas as espécies diferiu entre os bancos, tendo um decréscimo no consumo de invertebrados, principalmente aquáticos, e incremento no consumo de vegetal com o aumento da biomassa. Ademais, o consumo dos itens mostrou-se dependente da rentabilidade e acessibilidade deles no ambiente. A amplitude do nicho de ambas as espécies aumentou conforme houve um incremento na biomassa de macrófitas, porém não houve sobreposição do nicho entre elas. Os resultados mostraram que embora tenha ocorrido aumento na abundância de invertebrados, houve um decréscimo no consumo deste recurso, indicando que bancos com maior complexidade podem ser refúgios mais efetivos para os invertebrados aquáticos. Estes resultados indicaram o papel da complexidade do habitat em mediar a interação entre peixes e invertebrados, promovendo a coexistência entre eles, assim como a coexistência das espécies de peixes ecologicamente similares.

Description: Masters

Description: Habitat complexity is one of the main factors determining biological diversity and its assessment is a challenge that involves several variables. Submerged macrophytes are responsible for changes in habitat complexity and may enhance habitat conditions for different species. These plants usually colonize natural and artificial lentic environments, such as reservoirs, which have abiotic characteristics favorable to their establishment. The construction of the Itaipu Dam and the filling of the reservoir favored the establishment of macrophytes due to changes in flow dynamics. Therefore, the aim of this work was to evaluate whether habitat complexity, provided by macrophytes, is associated with changes in fish assemblage attributes (abundance, richness, and evenness) and composition. Linear regression models were applied to test the relationship between abundance, richness, and evenness with habitat complexity (expressed as macrophyte density - g/m²). In addition, Principal Coordinates Analysis (PCoA) and Spearman correlations were used to assess changes in the composition of fish assemblages according to macrophytes density. The results indicate a direct relationship between habitat complexity and fish assemblage attributes as well as associations between macrophyte density and fish assemblage composition, improving the knowledge about species preference for different levels of complexity. Thus, it is important to consider the behavior of species known to cause economic and ecological issues for future management and conservation efforts.

Description: A complexidade de habitat é um dos fatores determinantes para a manutenção da diversidade biológica e, avaliar sua influência, é um desafio que envolve muitas variáveis. As macrófitas submersas são responsáveis por alterar a complexidade dos habitats, podendo promover melhores condições de habitat para um maior número de espécies. Essas plantas geralmente colonizam ambientes lênticos naturais e, também, artificiais, como reservatórios, que possuem características abióticas favoráveis ao seu crescimento. A construção do reservatório de Itaipu favoreceu a proliferação de macrófitas devido às alterações na dinâmica da água. Avaliou-se a complexidade de habitat, proporcionada pelas macrófitas, está associada com mudanças nos atributos (abundância, riqueza e equitabilidade) e na composição da assembleia de peixes do reservatório de Itaipu. Foram utilizadas regressões lineares para verificar a relação entre a abundância, riqueza e equitabilidade com a complexidade de habitat (representada pela densidade de macrófitas - g/m²). Na sequência uma Análise de Coordenadas Principais (PCoA) e correlações de Spearman foram utilizadas para avaliaras alterações na composição das assembleias de acordo com a densidade de macrófitas. Houve relação direta entre a complexidade de habitat e os atributos das assembleias. Também foi possível identificar relações entre a densidade de macrófitas com a composição das assembleias, contribuindo com conhecimento relacionado à preferência de espécies por ambientes com determinados níveis de complexidade. Dessa forma, é importante considerar o comportamento de algumas dessas espécies, conhecidas por causarem prejuízos econômicos e ecológicos aos locais, para as ações de manejo e conservação futuras.

Description: Masters

Description: The objective was to redescribe Cambeva stawiarski, using internal morphological data, external morphology, morphometry and meristic data, through the revision of the type-material and material deposited in fish collections. In this process, we have also added comments on the possible Cambeva stawiarski type-locality and described a new species of Cambeva, endemic to the Rio Iguaçu basin, Brazil. Cambeva stawiarski and the new species are diagnosed by the number of procurrent caudal-fin rays dorsally and ventrally; number of vertebrae; number of pectoral-fin rays; number of branchiostegal rays; small notch on the distal margin of the caudal-fin; head length; caudal peduncle depth; and the colouration pattern of the body. In addition, the species are compared with other possibly related species and the synapomorphic characters of these groups of species are discussed. With confirmation of the endemism of Cambeva stawiaski and the description of a new species of Cambeva for the Rio Iguaçu basin, we confirm important biogeographic patterns on the endemism of this hydrographic basin and in the use of osteological data in the description of Cambeva species

Description: O objetivo foi redescrever Cambeva stawiarski, com base em dados morfológicos internos, morfologia externa, morfometria e dados merísticos, por meio da revisão do material tipo e de material depositado em coleções ictiológicas. Neste processo, fora acrescentado comentários sobre a possível localidade-tipo de Cambeva stawiarski e descreveu-se uma nova espécie de Cambeva, endêmica da bacia do rio Iguaçu, Brasil. Cambeva stawiarski e a nova espécie são diagnosticadas pela combinação de caracteres como número de raios procurrentes caudais dorsais e ventrais; número de vértebras; número de raios na nadadeira peitoral; número de raios branquiostegais; nadadeira caudal com pequeno entalhe na margem distal; comprimento da cabeça; altura do pedúnculo caudal; e padrão de colorido do corpo. As espécies também são comparadas com outras espécies possivelmente relacionadas e os caracteres sinapomórficos desses grupos de espécies são discutidos. Com a confirmação do endemismo de Cambeva stawiarski e a descrição de uma nova espécie de Cambeva para a bacia do rio Iguaçu, confirmamos importantes padrões biogeográficos sobre o endemismo da bacia hidrográfica e sobre a utilização de dados osteológicos na descrição de espécies de Cambeva.

Description: Masters

Description: Partitioning patterns of dissimilarity (beta diversity) into contributions of single sites or individual species is a modern approach to understanding what the main factors affect and cause variation in biodiversity. In this context, estimating the contributions of single sites to overall beta diversity (LCBD) or into contributions of individual species to overall beta diversity (SCBD) has proven to be a good approach to improve the knowledge of drivers of beta diversity. We explored the contributions of each site and species to the overall algae and cyanobacteria beta diversity of 77 natural freshwater micro-ecosystems (i.e., tank bromeliads) of a neotropical ecosystem. We found that LCBD was negatively affected by Shannon's diversity, turbidity, and luminosity (% canopy cover). Cyanobacteria and green algae were the groups that most contributed SCBD values. The negative relationship between LCBD and the Shannon index indicates that micro-ecosystems with less diversity reflect unique characteristics, and LCBD values can easily predict these environments. LCBD values can indicate these environments as priorities for management and conservation.

Description: Particionar padrões de dissimilaridade (diversidade beta) em contribuições dos locais ou de espécies é uma abordagem moderna para compreender quais os principais fatores afetam e provocam variação na biodiversidade. Neste contexto, estimar a contribuição local para o pool regional de espécies (LCBD) e a contribuição de cada espécies para a diversidade beta (SCBD) tem se mostrado uma eficiente abordagem para inferir sobre mecanismos condutores da diversidade beta. Nesse estudo foram exploradas as contribuições de cada local e espécies para a diversidade beta total de algas e cianobactérias de 77 microecossistemas naturais de água doce (i.e., bromélias-tanque) de um ecossistema neotropical. A LCBD foi afetada negativamente pela diversidade de Shannon, turbidez e luminosidade (% cobertura de dossel) A relação negativa do LCBD com o índice de Shannon indica que locais menos diversos podem refletir em ambientes com características específicas. Cianobactérias e fitoflagelados apresentaram maior contribuição para os valores de SCBD. A compreensão da influência do LCBD e SCBD na distribuição dos padrões da diversidade beta podem facilmente prever esses ambientes com características singulares, fazendo dos mesmos prioritários para práticas de manejo e conservação.

Description: Masters

Description: Given the great diversity of Neotropical fish species, as well as the importance of such organisms as a link within aquatic food chains, it is essential to assess different processes that drive the spatial organization of their communities. It is known that the structure of fish assemblages varies markedly in relation to space, depending on abiotic factors, biotic interactions, and dispersion processes. However, these determining factors in the structuring of fish communities vary indiscriminately in dammed aquatic bodies. The course of large rivers has been altered due to the construction of reservoirs and the number of projects under construction or inventoried has been increasing significantly in recent decades. Therefore, evaluating how the spatial organization of fish assemblages occurs in environments (i.e., dammed), as well as unraveling the predictors associated with this organization is of extremely important for conservation purposes and the implementation of management measures. To investigate such aspects in dammed environments, in the first study three cascades of reservoirs belonging to different hydrographic basins were studied, in which the effects of these reservoirs arranged in series on the patterns of diversity, distribution and richness of the assemblages were evaluated. In the second study, 29 reservoirs located in the state of Parana were evaluated in order to identify relationships between the organization of fish trophic guilds and environmental, spatial and morphological predictors. The results found suggest that, in most of the studied environments, the environmental changes caused by the construction of dams, as well as their morphological characteristics and modes of operation have negative effects on the diversity, distribution and abundance of fish species and exert an influence on the different fish trophic guilds.

Description: Dada a grande diversidade de espécies de peixes contidas na região Neotropical, bem como a importância desses organismos como elo nas cadeias tróficas aquáticas, se faz necessário conhecer os distintos processos que governam a organização espacial de suas comunidades. Sabe-se que a estrutura das assembleias de peixes varia acentuadamente em relação ao espaço a depender de fatores abióticos, interações bióticas e processos de dispersão. Entretanto, esses fatores determinantes na estruturação das comunidades de peixes variam indiscriminadamente em corpos aquáticos barrados. O curso de grandes rios tem sido alterado devido a construção de reservatórios e o numero de empreendimentos em construção ou inventariados vem aumentando significativamente nas ultimas décadas. Portanto, avaliar como ocorre a organização espacial das assembleias de peixes nesses ambientes (i.e., barrados), bem como desvendar os preditores associados a essa organização e de extrema importância para fins conservacionistas e implementações de medidas de manejo. Para investigar tais aspectos, na primeira abordagem foram estudadas três cascatas de reservatórios pertencentes a diferentes bacias hidrográficas, para avaliar os efeitos da disposição em serie dos reservatórios nos padrões de diversidade, distribuição e riqueza das assembleias de peixes. Na segunda abordagem, foram avaliados 29 reservatórios situados no estado do Paraná com o objetivo de identificar relações entre a organização das guildas tróficas de peixes com preditores ambientais, espaciais e morfológicos. Os resultados encontrados pelas duas abordagens sugerem que, na maioria dos reservatórios estudados, as alterações ambientais provocadas devido a construção de barragens, bem como suas características morfológicas e modos de operação tem efeitos negativos sobre a diversidade, distribuição e abundancia das espécies de peixes e exercem influencia sobre as diferentes guildas tróficas de peixes.

Description: PhD

Description: Biological invasion processes are complex phenomena and comprise one of the greatest challenges for the conservation of biodiversity in continental aquatic environments. The pressure of propagules, i.e., the number of non-native individuals released and the number of release events, is among the different mechanisms involved in these decisive processes for the successful establishment of non-native species. In this scenario, aquaculture is an important source of propagules of species with high invasive potential, such as Nile Tilapia (Oreochromis niloticus), as accidental escapes and intentional releases from production ponds are recurrent. Nine small streams, tributaries of the Piquiri River (Paraná, Brazil), were sampled to evaluate the effect of aquaculture on fish assemblages in neotropical streams. The watersheds of these streams differ in percentage of aquaculture occupation, and this difference was used as a proxy for propagule pressure of O. niloticus in natural environments. Therefore, the present research aimed to evaluate the effects of different intensities of aquaculture production of tilapia on the richness patterns, composition and structure of the ichthyofauna, testing the hypothesis that the increase in propagule pressure of this species alters the patterns of occurrence and abundance of assemblages, as well as discuss the effects of this species on the functional structure of ichthyofauna, observing the effect of aquaculture occupation on responses of functional diversity indexes and on dissimilarity patterns among the different streams. The results indicated that streams with no aquaculture occupation and with no presence of O. Niloticus had more similar compositions and differed in patterns of occurrence and distribution of ichthyofauna from streams under aquaculture activity. In addition, the presence of tilapia altered the functional diversity indexes in the streams, as the species presented more extreme traits that allow it to increase the functional space of receptor environments and promote greater niche differentiation. The results reinforce the potential of aquaculture as an important source of propagules of non-native species for natural environments and raise attention to the structuring power of tilapia on the taxonomic and functional composition of native ichthyofauna.

Description: Os processos de invasão biológica são fenômenos complexos e compreendem um dos maiores desafios para a conservação da biodiversidade em ambientes aquáticoscontinentais. Dentre os diferentes mecanismos envolvidos nesses processos, a pressão de propágulos, isto é, o número de indivíduos não nativos liberados e o número de eventos de liberação são determinantes no sucesso de estabelecimento de espécies não nativas. Neste cenário, a aquicultura se insere como uma importante fonte de propágulos de espécies com alto potencial invasor, a exemplo da Tilápia do Nilo, Oreochromis niloticus, uma vez que os escapes acidentais e as solturas intencionais dos tanques de produção são recorrentes. A fim de avaliar a influênciada aquiculturasobre as assembleias de peixes em riachos Neotropicais, nove riachos de pequena ordem,afluentes do rio Piquiriforam amostrados. Estes riachosdiferem quanto a porcentagem de ocupação aquícola emsuas microbacias, sendo essa diferença utilizada como um proxyda pressão de propágulos de O. niloticuspara ambientes naturais. Sendo assim, a presente pesquisa teve como objetivosavaliar os efeitos de diferentes intensidades deprodução aquícolada tilápiasobre os padrões de riqueza,composição eestrutura da ictiofauna, testando-se a hipótese de que o aumento da pressão de propágulos dessa espécie alteraos padrões deocorrência e deabundância das assembleias, bem comodiscutir os efeitosdessa mesma espécie sobre a estrutura funcional da ictiofauna, observando-se a influência da ocupação aquícola nas respostas dos índices de diversidade funcional e nos padrões de dissimilaridade entre os diferentes riachos. Os resultados indicaramqueriachos sem ocupação aquícola e sem a presença deO. niloticusforammais similares em suas composiçõese diferiramnospadrões de ocorrência e distribuição da ictiofauna dos riachos com atividade aquícola. Observou-se também a presença da espécie alterou os índices de diversidade funcional entre os riachos, por apresentar traços mais extremos que lhe permitem aumentar o espaço funcional dos ambientes receptores e promover maior diferenciação de nicho. Os resultados reforçam o potencial da aquicultura como uma fonte importante de propágulos de espécies não nativas para ambientes naturais e atentam para o poder estruturador da tilápia sobre a composição taxonômica e funcional da ictiofauna nativa.

Description: PhD

Description: Our knowledge on temporal and fine- and broad-scale patterns of biodiversity, as a basis for biogeographical models and conservation planning, have been few explored to two fundamental components of beta diversity: replacement and richness difference. Whether variability in these components of beta diversity is congruent in space and time for disparate biological groups, which show wide variation in functional traits (e.g., dispersal mode), is, hitherto, unknown. Moreover, one of the main standing paradigms is to understand whether the empirical biogeographic patterns of macro-organisms also apply to micro-organisms. This thesis consists of three papers. The first one aimed to determine whether the cross-taxon congruence of taxonomic and functional beta diversity and its components varies across space, and time. Our results showed how detailed hierarchical analyses can reveal hidden patterns of cross-taxon congruence. We partly supported the hypothesis that the strength of cross-taxon congruence generally decreases with the increase of functional distances between pairs of biological groups. In the second paper, we contrasted longitudinal patterns in the total beta diversity and its components in the last non-dammed stretch of the Paraná River for actively (fish) and passively (phytoplankton) dispersing biological groups. The results ratify that biodiversity patterns exhibited by single biological groups do not necessarily match those of other groups that show wide variation in biological features. Our findings have improved understanding of tributary-induced heterogeneity and highlight the importance of dam-free stretches of rivers for preserving its integrity. In the third paper, we used morphological data from live organisms and molecular data to verify which approach better explain the role of environmental and spatial predictors on the ciliates structuration, as well as clarify their biogeography. We found that environmental filters had a greater influence on the morphological than on the molecular site-by-site dissimilarities. Meanwhile, biogeographic factors and the distance among sites limit the distribution of molecular-based composition, resulting in significantly different species compositions in each of the floodplain-associated lakes analyzed. In summary, the findings of this thesis suggest that conservation biology and environmental assessment need to monitor different biological groups, as well as take into account for the choice of taxonomic resolution, as each group and approach provides unique insights.

Description: O conhecimento sobre padrões temporais e espaciais locais e regionais da biodiversidade, como base para modelos biogeográficos e planejamento de conservação, foi pouco explorado para dois componentes fundamentais da diversidade beta: substituição e diferença de riqueza. Avaliar até que ponto a variabilidade nesses componentes da diversidade beta é congruente no espaço e no tempo para grupos biológicos distintos, que possuem ampla variação em suas características funcionais (por exemplo, modo de dispersão) é, até agora, desconhecido. Ademais, um dos principais paradigmas da ecologia é entender se os padrões biogeográficos empíricos dos macrorganismos também se aplicam aos microrganismos. Assim, esta tese é composta por três segmentos. O primeiro teve como objetivo determinar se a congruência entre táxons da diversidade beta taxonômica e funcional e seus componentes variam ao longo do espaço e do tempo. Os resultados mostraram como análises hierárquicas detalhadas podem revelar padrões ocultos de congruência entre táxons. Foi apoiada parcialmente a hipótese de que a força da congruência entre táxons geralmente diminui com o aumento das distâncias funcionais entre pares de grupos biológicos. No segundo segmento, foram contrastados padrões longitudinais na diversidade beta total e seus componentes no último trecho não represado do rio Paraná para grupos biológicos de dispersão ativa (peixe) e passiva (fitoplâncton). Os resultados ratificam que os padrões de biodiversidade exibidos por grupos biológicos únicos não coincidem necessariamente com os de outros grupos que mostram grande variação nas características biológicas. Estas descobertas melhoram a compreensão da heterogeneidade induzida por tributários e destacam a importância dos trechos de rios livre de barramentos para preservar sua integridade. No terceiro segmento, foram utilizados dados morfológicos de organismos vivos e dados moleculares para verificar qual abordagem explica melhor o papel dos preditores ambientais e espaciais na estruturação de protistas ciliados, bem como tentar esclarecer sua biogeografia. Foi demonstrado que os filtros ambientais tiveram uma maior influência na dissimilaridade par a par baseada em dados morfológicos do que nas baseadas em dados moleculares. Entretanto, fatores biogeográficos, impostos pela distância entre os locais, limitam a distribuição da composição baseada em dados moleculares, resultando em composições de espécies significativamente distintas em cada um dos lagos associados às planícies de inundação analisadas. Em resumo, os resultados desta tese demonstram que a biologia da conservação e a avaliação ambiental precisam monitorar diferentes grupos biológicos, bem como levar em consideração a escolha da resolução taxonômica, pois cada grupo e abordagem fornecem insights exclusivos.

Description: PhD

Description: Author Posting. © American Meteorological Society, 2021. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Applied Meteorology and Climatology 60(9), (2021): 1361–1370, https://doi.org/10.1175/JAMC-D-20-0254.1.

Description: We analyze how winter thaw events (TE; T 〉 0°C) are changing on the summit of Mount Washington, New Hampshire, using three metrics: the number of TE, number of thaw hours, and number of thaw degree-hours for temperature and dewpoint for winters from 1935/36 to 2019/20. The impact of temperature-only TE and dewpoint TE on snow depth are compared to quantify the different impacts of sensible-only heating and sensible-and-latent heating, respectively. Results reveal that temperature and dewpoint TE for all metrics increased at a statistically significant rate (p 〈 0.05) over the full time periods studied for temperature (1935/36–2019/20) and dewpoint (1939/40–2019/20). Notably, around 2000/01, the positive trends increased for most variables, including dewpoint-thaw degree-hours that increased by 82.11 degree-hours decade−1 during 2000–20, which is approximately 5 times as faster as the 1939–2020 rate of 17.70 degree-hours decade−1. Furthermore, a clear upward shift occurred around 1990 in the lowest winter values of thaw hours and thaw degree-hours—winters now have a higher baseline amount of thaw than before 1990. Snow-depth loss during dewpoint TE (0.36 cm h−1) occurred more than 2 times as fast as temperature-only TE (0.14 cm h−1). With winters projected to warm throughout the twenty-first century in the northeastern United States, it is expected that the trends in winter thaw events, and the sensible and latent energy that they bring, will continue to rise and lead to more frequent winter flooding, fewer days of good quality snow for winter recreation, and changes in ecosystem function.

Description: Ecosystems respond to the direct, indirect and synergistic effects of global changes caused by human activity. The understanding of the impacts of these changes and especially of the interaction between the impacts is still limited, especially for aquatic environments, because the interaction between them is rarely considered in environmental studies and assessments. We conducted a systematic literature review on the combination of the factors (i) increase of CO2, (ii) eutrophication and (iii) non-native species to verify how these factors have been considered in the context of climate change in freshwater ecosystems studies. Through the Web of Science database, we searched for articles published in English, up to 2020. Following the PRISMA protocol, 62 articles were analyzed. Only 8% of them addressed the combination of the three factors, among them, eutrophication was the most evaluated global change. Still, the studies do not seem to be looking for answers in a broad way and covering several ecological aspects, since they are concentrated in specific regions such as the Netherlands and United States (44%). Studies most focus on one type of environment, the lentic; use organisms from the base of the food-web; apply the experimental approach; evaluate one organizational level (community) and one response variable (biomass). We identified that the effect of the combination of factors is rarely classified with the terms synergistic and antagonist, even when the authors find these patterns. Our main findings reveal that little attention has been given to the combination of factors in freshwater ecosystems. We also find that when interactions are considered, non-native species tend to be favored and algal blooms intensified (74%). Considering that one of the major challenges is to understand how the interaction between global change factors will affect ecosystems, the combinations of factors still need to be prioritized in studies of aquatic ecosystems.

Description: Os ecossistemas respondem aos efeitos diretos, indiretos e sinérgicos das mudanças globais causadas pela atividade humana. A compreensão sobre os impactos dessas mudanças e principalmente da interação entres os impactos ainda é limitada, especialmente para os ambientes aquáticos, pois raramente a interação entre eles é considerada nos estudos e avaliações ambientais. Realizou-se uma revisão sistemática da literatura para verificar como a combinação dos fatores: (i) aumento da concentração de CO2, (ii) eutrofização, e (iii) espécies não nativas, está sendo abordada no contexto de mudanças globais em ecossistemas aquáticos continentais. Por meio da plataforma Web of Science, procurou-se por artigos publicados em inglês, até 2020. Seguindo o protocolo PRISMA, 62 artigos foram analisados. Apenas 8% dos estudos abordaram a combinação dos três fatores, dentre eles, a eutrofização foi o fator de mudança global mais avaliado. Ainda, os estudos não parecem estar buscando respostas de forma ampla e abrangendo diversos aspectos ecológicos, visto que, se concentram em regiões específicas, na Holanda e nos Estados Unidos (44%), focam em ambientes lênticos; utilizam majoritariamente organismos da base da cadeia trófica; são em sua maioria experimentais; e avaliam um nível organizacional (comunidade) e uma variável resposta (biomassa). Raramente o efeito da combinação dos fatores é classificado com os termos sinérgico e antagônico, mesmo quando os autores encontram esses padrões. Como resultados principais evidenciou-se que pouca atenção tem sido dada à combinação dos fatores nos ecossistemas aquáticos continentais. Os estudos analisados mostraram que quando consideradas as interações, espécies não nativas tendem a ser favorecidas e florações algais intensificadas (74%). Considerando que um dos maiores desafios atuais é compreender como a interação entre fatores de mudanças globais afetará os ecossistemas, a combinação de fatores ainda precisa ser priorizada nos estudos dos ecossistemas aquáticos.

Description: Masters

Description: Atmospheric delay corrections for satellite altimetry measurements are essential for deriving highly accurate sea surface heights and reliable global mean sea level (GMSL) trend estimates. A commonly used method to correct for ionospheric path delays are the usage of GNSS‐based Global Ionospheric Maps (GIM). The different orbit heights of GNSS and altimeter satellites require an adaption of GIM corrections to account for free electrons in the Earth plasmasphere. This study shows that the widely used scaling approach based on the International Reference Ionosphere (IRI) is not able to accurately scale the GIM models. The impact of neglecting the plasmaspheric part of the atmosphere strongly correlates with the solar activity of about 11 years. This manifests itself as trend errors in global GMSL. For the Jason period (2002–2021) a trend error of 0.17 mm/year can be shown, which is even larger for smaller periods (e.g., 1.0 mm/year for Jason‐1 lifetime). The application of an additional constant scaling factor of 0.886 can reduce the trend differences to below 0.05 mm/year.

Description: Plain Language Summary: Global mean sea level (GMSL) rise is an important indicator for climate change. To precisely measure this quantity that is only in the order of about 3 mm/year, satellite altimeters are used. Their observations have to be corrected for influences in the Earth atmosphere. This study shows deficiencies in one commonly used correction data set. These corrections, based on observations from the Global Navigation Satellite Systems (GNSS) are not accounting for the higher part of the atmosphere, the plasmasphere. Neglecting this influence derives systematic errors with a 11 years cycle that impacts the estimation of GMSL by up to 1 mm/year, depending on the period under investigation. It is recommended to apply an additional scaling of the available corrections in order to reduce the trend error to below 0.05 mm/year.

Description: Key Points: Global Ionospheric Map corrections in altimetry Sensor Geophysical Data Records are not fully scaled to account for plasmaspheric electron content. Neglecting the plasmaspheric effect leads to trends of up to 1 mm/year in Global mean sea level estimates. The additional application of a scale factor improves the consistency in trend with respect to dual‐frequency satellite altimetry data.

Description: https://podaac.jpl.nasa.gov/

Description: https://www.aviso.altimetry.fr/

Description: https://openadb.dgfi.tum.de/en/products/vertical-total-electron-content/

Description: Species are exposed to natural climate change throughout their evolutionary history. However, anomalous global warming and resulting variations in rainfall patterns affect survival, alter the distribution of organisms and the network of species interactions. The aim of this thesis was to find larger-scale (basin and biome level) patterns for the possible effects of climate change on the distribution of South American freshwater ostracods through ensemble analysis of several species-distribution modelling algorithms. Here, climate change was based on two assumptions of increasing carbon emissions, the moderate-optimistic (RCP 4.5) and pessimistic (RCP 8.5) scenarios of four climate models (AOGCMs), from 2050 and 2080. In the first approach, projections of changes in ostracod species richness and composition were presented, and conservation status of 61 species from 13 river basins in the Southern Cone. In the second approach, the geographical pattern of a symbiotic interspecific interaction of commensalism type was evaluated through the climatic suitability of Elpidium (Ostracoda) and tank bromeliads of the Atlantic Forest, and the availability of habitat for Elpidium (presence of tank bromeliads) in the future. For both approaches, climate change directly influenced the decrease in future distribution areas of ostracods. The results of the first approach showed a decrease in ostracod richness in the Southern Cone basins of South America, and different species compositions in 2050 and 2080, in both the moderate-optimistic and pessimistic scenarios. The decrease in the ranges of ostracods will change the conservation status of several species to “potentially threatened”. Elpidium ranges will be more limited in the future, and there will be less habitat availability, i.e. fewer tank bromeliad species for interaction. In general, precipitation and temperature regimes are synchronized with phenological life-history events of the species, which determine the direction of dispersal to the environmental set of optimal survival conditions in the future. Our results contribute to the inclusion of ostracods (and other invertebrates) in conservation plans for their habitats on larger geographical scales.

Description: Espécies estão expostas às mudanças climáticas naturais ao longo de sua história evolutiva, entretanto o aquecimento global anômalo e as variações resultantes nos padrões pluviométricos afetam a sobrevivência, alteram a distribuição dos organismos e a rede de interações das espécies. O objetivo desta tese foi encontrar padrões em maior escala (nível de bacia e bioma) dos possíveis efeitos da mudança climática sobre a distribuição de ostrácodes de água doce da América do Sul, através de análise conjunta de diversos algoritmos de modelagem de distribuição de espécies. A mudança climática foi baseada em duas hipóteses de aumento das emissões de carbono, os cenários moderado-otimista (RCP 4.5) e pessimista (RCP 8.5) de quatro modelos climáticos (AOGCMs) de 2050 e 2080. Na primeira abordagem foram apresentadas projeções de mudanças na riqueza e composição de espécies de ostrácodes e status de conservação de 61 espécies de treze bacias hidrográficas no Cone Sul. Na segunda abordagem foi avaliado o padrão geográfico de uma interação interespecífica simbiótica do tipo comensalismo através da adequabilidade climática de Elpidium (Ostracoda) e bromélias tanque da Mata Atlântica, além da disponibilidade de habitat para o Elpidium (presença de bromélias tanque) no futuro. Para ambas as abordagens, a mudança climática influenciou diretamente a diminuição das áreas de distribuição dos ostrácodes no futuro. Os resultados da primeira abordagem mostraram uma diminuição da riqueza de ostrácodes nas bacias do Cone Sul da América do Sul, e diferentes composições de espécies em 2050 e 2080, em ambos os cenários moderado-otimista e pessimista. A diminuição nas áreas de distribuição de ostrácodes alterará o status de conservação de diversas espécies para potencialmente ameaçadas. As áreas de ocorrência de Elpidium serão mais limitadas em tempos futuros e haverá menor disponibilidade de habitat, ou seja, menos espécies de bromélias tanque para interação. Em geral, os regimes de precipitação e temperatura são sincronizados com eventos fenológicos de história de vida das espécies, os quais determinam a direção da dispersão para o conjunto ambiental das condições ideais de sobrevivência no futuro. Os resultados contribuem como subsídio para incluir ostrácodes (e outros invertebrados) em planos de conservação de seus habitats em escalas geográficas mais amplas.

Description: PhD

Description: The paleolimnological approach one of the few existing methods that assesses the rate of ecosystem changes in freshwater environments, over large time scales, and one of the few approaches that have been used successfully to infer pre-impact limnological conditions and post-perturbation trajectories of environmental changes. The diatoms are the most effective bioindicator microfossils in paleolimnological research in providing information on environmental changes in aquatic ecosystems. Among the ecosystems that have been altered over time, the floodplain of the Upper Paraná River in recent decades has been subjected to several natural and man-made disturbances, mainly hydroelectric dams, which have affected the entire ecosystem and the known freshwater biodiversity. Therefore, the temporal pattern of abundance and functional traits of the diatoms community of two lakes inserted in this floodplain was investigated, using the paleolimnological approach to infer a history of possible environmental changes. The results of these studies were divided into three works. Through the bioindication of the most abundant diatom species in Garças Lake and Patos Lake, it was possible to observe evidence of physical, chemical and hydrological changes in both environments over the last 100 years. It is inferred that both environments may have been influenced by effects imposed by the upstream reservoirs and climatic events. As well as the greater variation and reduction in functional diversity found in Garças Lake, which is closer to dams, indicates a greater influence of the reservoirs. Despite this, in different periods, both lakes have replaced and simplified similar functional categories, which are related to low water conditions and high turbulence in the water column, which were recurrent after the damming periods

Description: A abordagem paleolimnológica é um dos poucos métodos existentes que avalia a taxa de alterações ecossistêmicas em ambientes de água doce em grandes escalas temporais e uma das poucas abordagens que têm sido usada com sucesso para inferir condições limnológicas pré-impacto e trajetórias pós-perturbação de mudanças ambientais. Sendo as diatomáceas os microfósseis bioindicadores mais eficazes na pesquisa paleolimnológica no fornecimento de informações sobre alterações ambientais nos ecossistemas aquáticos. Dentre os ecossistemas que tem sido alterado ao longo do tempo, tem-se como exemplo a Planície de inundação do alto rio Paraná, a qual nas últimas décadas tem sido submetida a diversos distúrbios naturais e antrópicos, principalmente por represas hidrelétricas, que afetaram todo o ecossistema e a biodiversidade de água doce conhecida. Portanto, investigou-se o padrão temporal da abundância e de traços funcionais da comunidade de diatomáceas de dois lagos inseridos nesta planície de inundação, utilizando a abordagem paleolimnológica para inferir um histórico de possíveis mudanças ambientais. Através da bioindicação das espécies de diatomáceas mais abundantes do lago das Garças e do lago dos Patos, foi possível observar evidências de mudanças físicas, químicas e hidrológicas em ambos os ambientes nos aproximados últimos 100 anos. Infere-se que ambos os ambientes podem ter tido influência de efeitos impostos pelos reservatórios a montante e eventos climáticos. Como também a maior variação e redução da diversidade funcional encontrado no lago das Garças, o qual está mais próximo de barragens, indica uma maior influência dos represamentos. Apesar disso, em períodos distintos, ambos os lagos apresentaram substituição e simplificação de categorias funcionais similares, as quais estão relacionadas com condições de águas baixas e alta turbulência da coluna d’água, as quais foram recorrentes após os períodos de represamento.

Description: PhD

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Clark, S., Hubbard, K., Ralston, D., McGillicuddy, D., Stock, C., Alexander, M., & Curchitser, E. Projected effects of climate change on Pseudo-nitzschia bloom dynamics in the Gulf of Maine. Journal of Marine Systems, 230, (2022): 103737, https://doi.org/10.1016/j.jmarsys.2022.103737.

Description: Worldwide, warming ocean temperatures have contributed to extreme harmful algal bloom events and shifts in phytoplankton species composition. In 2016 in the Gulf of Maine (GOM), an unprecedented Pseudo-nitzschia bloom led to the first domoic-acid induced shellfishery closures in the region. Potential links between climate change, warming temperatures, and the GOM Pseudo-nitzschia assemblage, however, remain unexplored. In this study, a global climate change projection previously downscaled to 7-km resolution for the Northwest Atlantic was further refined with a 1–3-km resolution simulation of the GOM to investigate the effects of climate change on HAB dynamics. A 25-year time slice of projected conditions at the end of the 21st century (2073–2097) was compared to a 25-year hindcast of contemporary ocean conditions (1994–2018) and analyzed for changes to GOM inflows, transport, and Pseudo-nitzschia australis growth potential. On average, climate change is predicted to lead to increased temperatures, decreased salinity, and increased stratification in the GOM, with the largest changes occurring in the late summer. Inflows from the Scotian Shelf are projected to increase, and alongshore transport in the Eastern Maine Coastal Current is projected to intensify. Increasing ocean temperatures will likely make P. australis growth conditions less favorable in the southern and western GOM but improve P. australis growth conditions in the eastern GOM, including a later growing season in the fall, and a longer growing season in the spring. Combined, these changes suggest that P. australis blooms in the eastern GOM could intensify in the 21st century, and that the overall Pseudo-nitzschia species assemblage might shift to warmer-adapted species such as P. plurisecta or other Pseudo-nitzschia species that may be introduced.

Description: This research was funded by the National Science Foundation (Grant Number OCE-1840381), the National Institute of Environmental Health Sciences (Grant Number 1P01ES028938), the Woods Hole Center for Oceans and Human Health, and the Academic Programs Office of the Woods Hole Oceanographic Institution.

Description: Im Steinbruch der Firma Balz (Pappenheim) wurde ein Intervall von 18 m Mächtigkeit im Bereich der Unteren Mergelplatte und der Oberen Mergelplatte (Grenzbereich Malm Delta 1-3) der Treuchtlingen Formation untersucht. Die Schichtfolge (16 Bänke; Schichten) kann über mehrere 10-er Kilometer in der Südlichen Frankenalb korreliert werden. Die Bänke sind durch deutliche »Hauptfugen« voneinander getrennt und zeigen oft auch schwach ausgebildete Bank-interne »Nebenfugen«. Die mikrofazielle Analyse wurde anhand von 22 Proben mittels petrographischer Dünnschliffe und röntgenographischer-Analysen zur Ermittlung der tonmineralogischen Zusammensetzung der Nichtkarbonate durchgeführt. Die Bänke bauen sich aus Horizonten verschiedener Partikelkalke (Mikrofazies-Typen) mit charakteristischen Karbonatgehalten auf. Matrix-reiche Wackestones (92-96% Karbonatgehalt), Partikel-reiche Packstones und mikrobielle Bindstones (94-98%) wechseln sich in vertikaler Folge ab. Eingeschaltete Mergel sind entsprechend ihres Anteils an Nichtkarbonaten unterschiedlich ausgebildet. Die Partikelkalke zeigen wechselnde Matrix-Gehalte und Mächtigkeiten von Zentimetern bis Dezimetern innerhalb der Bänke. Sie spiegeln einen stetigen Wechsel der Wasserenergie von gering bis mäßig im Ablagerungsraum wider. Dünne Schalen planktonischer Bivalven (Filamente) wurden zu Zeiten erhöhter Wasserenergie aus entfernten, südlichen Meeresbereichen eingeschwemmt. Mikrobielle Lagen deuten auf eine Fixierung von vorher abgelagerten Sedimenten. Mikrobielle Aktivität führte zu dünnen, mikrobiellen Sedimentlagen, zu rundlichen Onkoiden mit mikritischen Kernen und zur Bildung von länglichen Filament-Onkoiden mit dünnen, langen Filamenten als Kern. Kleine domförmige mikrobielle »Stromatolithe«, Zusammenwachen von Tubiphyten und Serpuliden in kleinen Clustern stellen kleine riffogene Strukturen dar, die lokal am Meeresbodens wachsen konnten, der nur ein geringes Relief von Zentimeter bis Dezimeter Höhe aufgewiesen hat. Röntgenographisch, tonmineralogische Untersuchen zeigen vier Zonen unterschiedlicher Zusammensetzung der Tonmineral-Vergesellschaftung. Eine basale Mica-Chlorit-Zone wird von einer Kaolinit-Mica-Montmorillonit-Zone überlagert, die an der Unteren Mergelplatte endet. Der Bereich zwischen der Unteren und der Oberen Mergelplatte (Bank 19 bis Bank 25) weist in der liegenden Hälfte eine Mica-Mixed-Layer-Montmorillonit-Zone mit Spuren von Chlorit und eine Mica-Montmorillonit-Zone im oberen Teil auf. Zusammenhänge zwischen dem Vorkommen von Onkoiden und Filament-Onkoiden sowie den Tonmineral-Assoziationen deuten auf spezifische klimatologische Bedingungen hin. Die Entwicklung eines tropisch humiden zu einem tropischen, semi-ariden Klima mit entsprechendem Verwitterungspotential kristalliner Gesteine des nahen Böhmischen Massivs und Bildungsbedingungen der Tonmineral-Assoziationen im Untersuchungsbereich ist wahrscheinlich

Description: research

Description: Die verschiedenen architektonischen Baustile in einer Stadt geben der Nachwelt jeweils Zeugnis von der kulturellen und politischen Entwicklung. Dabei spielen die Baumaterialien vom historischen Naturstein bis hin zu den heute modernen technologischen Materialien (Kunststein, Glasbausteine, Beton, Metall etc.) eine wesentliche Rolle. Viele Jahrhunderte lang stand nur eine sehr begrenzte Palette an Naturwerksteinen zur Verfügung und es wurden zunächst sogenannte „Weichgesteine“ (Sandsteine, Kalkstein) genutzt, die leicht abzubauen und zu verarbeiten waren und die aus nahe gelegenen Abbaugebieten (»Steinbruch vor der Haustür«) stammten, oder auf Flüssen antransportiert werden konnten. Deshalb sind ältere Ortschaften und Städte durch eine lokalspezifische Gesteinsmonotonie gekennzeichnet, was sich in Erlangen in der Verwendung des in der Stadt und in der nahen Umgebung anstehenden Burgsandsteins widerspiegelt. Mitte des 19. Jahrhunderts traten für den technischen Aufschwung in der Steinindustrie entscheidende Veränderungen ein. Aufgrund der verbesserten maschinellen Bearbeitung kamen auch hier nun vermehrt Hartgesteine (Granit,Gabbro, Basalt) zur Verwendung. Durch neue Transportmöglichkeiten (Kanäle, Straße, Schiene) wurde auch die Einfuhr »exotischer Fremdgesteine« aus weitentfernten Abbaugebieten möglich. Seit der zweiten Hälfte des 19. Jahrhunderts kamen Kunststeine hinzu, mit denen natürliche Gesteine häufig perfekt imitiert werden können. Besondere politische Ereignisse, wie z. B. der deutsch französische Krieg (1870-1871) und damit zusammenhängend die Lieferungen von Fremdgesteinen nach Deutschland als Reparationsleistungen (Savonnières Kalkstein, Napoléon Kalkstein) dokumentieren noch heute markante Einschnitte in der Palette der verwendeten Naturwerksteine. In einem relativ engen Zeitfenster von der Hochzeit der Industrialisierung und auch der Deutschen Steinindustrie bis zu Beginn des ersten Weltkrieges (1900-1914) können diese vielschichtigen Einflüsse anhand von vier, in diesem Zeittraum errichteten Bauwerken in Erlangen exemplarisch aufgezeigt werden. Dabei geben auch die jeweiligen Zeitspannen von der Planung bis zur Fertigstellung und Einweihung der Gebäude Hinweise auf die politische und bautechnische Situation. Das Christian-Ernst-Gymnasium wurde aus der Prinz-Ludwig-Schule vom ersten Spatenstich im November 1901 bis zur Einweihung im November 1902 in nur einem Jahr fertig gestellt. Das Marie-Therese-Gymnasium, welches als neues Schulhaus in der Schillerstraße aus der »Städtischen höheren Töchterschule« hervorgegangen ist, wurde 1909 eingeweiht und erst 1965 offiziell als städtisches Marie-Therese-Gymnasium benannt. Die Universitätsbibliothek wurde 1910 geplant und nach der Grundsteinlegung 1911 bereits nach 2 Jahren Bauzeit im November 1913 eröffnet. Dabei hat der Termin des 170. Geburtstages der Friedrich-Alexander-Universität am 4. November 1913 sicher für entsprechenden Zeitdruck gesorgt und die Bauarbeiten beschleunigt. Der Bau des Instituts für Angewandten Chemie, der wahrscheinlich auch zur Unterstützung der Forschung an kriegswichtigen Materialen schnell errichtet werden musste, wurde nach kurzer Planung 1914 begonnen. Doch führten dann kriegsbedingte Schwierigkeiten, wozu wahrscheinlich auch der Mangel an Arbeitskräften aufgrund der Mobilmachung gehörte, zu großen Verzögerungen, weshalb der Rohbau erst 1916 fertiggestellt wurde und das Institut erst zum Wintersemester 1920 nach dem ersten Weltkrieg (1914-1918) bezogen werden konnte. Die Gestaltung der Front des Christian-Ernst-Gymnasiums, der Eingangsbereiche mit Portalen und Knaben- und Mädchenkopf aus schönem Roten Mainsandstein sowie einer darüber befindlichen Sandsteinbalustrade mit kunstvoll behauenen Vasen zeugen von einem ausgewogenen, repräsentativen Baustil. Die bronzene Büste des Prinzregenten auf einem Sockel aus ausgesuchtem hellem Untersberger Marmor (Kalkstein) sowie die ganze Gestaltung des Eingangsbereichs dokumentieren die positive Einstellung der Erlanger Bürger zu diesem Bauwerk. Die Gestaltung des Innenbereichs mit Wasserbecken aus poliertem Treuchtlinger Kalkstein sowie den beiden großzügig gestalteten Treppenhäusern mit Stufen aus Nammering Granit und schönen Holzbalustern bezeugen ebenso die gelungene architektonische Gesamtplanung wie auch die leider nicht mehr vollständig erhaltenen, geschwungenen Oberlichter über den Eichentüren zu den einzelnen Räumen. Auch die Gestaltung der Fußböden in den Gängen mit geschmackvollem Schwarz-Weiß-Muster der Bodenfliesen, die damals eine moderne technische Entwicklung (Trockenpressen) darstellten, lässt die Wertschätzung des Schulbaus bei den Bürgern und Architekten erkennen. Der Schulbau spiegelt auch heute noch die Freude am schönen Gestalten wider, die man damals hatte und in kurzer Zeit umsetzte und wirkt auch im Inneren heute noch fast fröhlich durch die von den beiden Treppenhäusern ausgehenden, lichtdurchflossenen Flure. Der heute als Marie-Therese-Gymnasium bekannt Bau in der Schillerstraße wurde etwa sieben Jahre später ebenfalls in sehr kurzer Bauzeit von der Planung 1908 bis zum Bezug 1909 des Neubau errichtet, der zunächst zur Unterbringung der »Städtischen höheren weiblichen Bildungsanstalt« diente. Der aufwändige neubarocke Stil ist trotz nachfolgender Veränderungen gut erhalten geblieben und zeigt auch noch das Chörlein an der Ostfassade vor dem 1956 erfolgten Erweiterungsbau. Muschelkalk und Coburger Bausandstein wurden für die Fassade ebenso wie am Christian-Ernst-Gymnasium verwendet und dokumentieren den Stil eines Schulbaus zu dieser Zeit. Doch wurden die Schmuckelemente des Eingangsportals mit großen Figuren und des großen Bayernwappens am Marie-Therese- Gymnasium aus grobporigem Muschelkalk geschlagen und kein feinkörniger Sandstein zur Modellierung verwendet. Eine Eingangshalle und ein trotz der Rundbögen geradliniges, kantig erscheinendes zentrales Treppenhaus weisen mehr auf einen pragmatischen Baustil im Inneren hin. Dieser Eindruck wird sowohl durch die intensive Verwendung von grobem Betonkunststein in Pfeilern und Balustern als auch durch einfarbige dunkelgrüne Wandfliesen und die teilweise verwendeten roten Bodenfliesen unterstützt. Die großen Keramikausgussbecken und besonders der Fußboden aus Linoleum, das sich in der zweiten Hälfte des 19. Jahrhunderts als moderner elastischer Bodenbelag durchgesetzt hat, zeigen im Innenbereich eine andere als im Christian-Ernst-Gymnasium, aber ebenfalls eine dem Stand der Technik zeitgemäße, moderne Gestaltung. Die ehemals verglasten, bunten Oberlichter, die dem Bau ein lichtdurchflossenes fröhliches Bild gaben, sind leider nicht mehr erhalten, weshalb der Eindruck im Inneren eher etwas klamm und gedämpft ist. Der geplante Besuch der Königsfamilie Ende Juli 1914 kam aufgrund des sich abzeichnenden Weltkrieges nicht zu Stande. Zu Ehren der Königin aber gab man dem Bau den Namen »Marie-Therese-Schule«, der 1965 von der Stadt in »Marie-Therese-Gymnasium« umgewandelt wurde. Der Neubau der Universitätsbibliothek, der 1910 geplant wurde, spiegelt in seinen beiden Teilen, dem Magazin- und dem Verwaltungstrakt eine komplexe Planungs- und Baugeschichte wider. Die Besuche der Planer von damals modernen Universitätsbibliotheken in anderen Universitätsstädten haben zu einem innovativen, dem neuesten Stand der Technik entsprechenden Magazintrakt mit selbst tragender Stahlkonstruktion geführt. Für den Außenbereich war die architektonische Eingliederung in die benachbarten Universitätsbauten im Markgrafenstil wie dem Kollegienhaus die Vorgabe. Dies wurde durch den Abriss der Reifbrauerei und die dadurch zur Verfügung stehenden Burgsandsteinquader begünstigt. Auch dass deren Menge nicht ausreichte, stellte kein Hindernis dar, konnten in dieser Zeit der Blüte von Steinbruchunternehmen doch problemlos zwei neue Brüche am Burgberg eröffnet werden. Die Gestaltung des Innenbereichs zeichnet sich durch architektonische, künstlerische Elemente aus, die sowohl durch Holzvertäfelung und Einbauten im Direktorenbereich und Sitzungssaal als auch durch die Auswahl der Naturwerksteine im Treppenhaus und in den Fluren einen repräsentativen Gesamteindruck vermitteln. Doch scheint hier gegen Ende der durch das 170-jährige Universitätsjubiläum (4. November 1913) vorgegebenen Bauzeit Zeitdruck entstanden zu sein, so dass manche Natursteinarbeiten nicht mehr mit der vorgesehenen Sorgfalt ausgeführt wurden. Dieser Umstand spiegelt sich besonders in den beidseitigen kastenartigen Konstruktionen aus nur 2 cm starken, schlecht verfugten Platten des Kalksteins Napoléon wider, die beidseitig des Treppenaufgangs angefertigt und mit zierlichen, zu klein erscheinenden Handläufen versehen wurden. Es kann angenommen werden, dass die Kalksteinplatten aus Reparationsleistungen des Deutsch-Französischen Krieges zu den Marmorwerken Funk in Nürnberg gelangt sind und hier verbaut wurden. In anderen repräsentativen Gebäuden dieser Zeit sind oft massive Geländer aus poliertem, edlem Naturstein zu finden. Auch die Platten aus Napoléon-Kalkstein in den Fluren erscheinen etwas rasch angebracht worden zu sein. Die grobkörnigen, bräunlichen Betonkunststeine aus denen die kurzen Mäuerchen mit Durchbruch und Holzbalustern und die Pfeiler hergestellt wurden, wirken leicht störend im gesamten repräsentativen Erscheinungsbild des Treppenhauses. Die schönen Rundbögen mit Kartuschen an den Eingängen zu den Fluren und vor allem die großen lichtgebenden Fenster aus Antikglas mit ziselierter Ornamentik verleihen dem Treppenhaus dagegen seinen großzügigen Eindruck. Das Gebäude der Universitätsbibliothek spiegelt den Wunsch nach einem hochmodernen (Magazintrakt) und gleichzeitig repräsentativen Gebäude (Verwaltungstrakt) wider. Die vollständige Umsetzung dieses Plans scheint unter dem Zeitdruck gelitten zu haben. Man griff daher wohl auch auf gerade verfügbares Material zurück, das wahrscheinlich günstig zu haben war und verwendete größere massive Kalksteine (Napoléon und Treuchtlinger Kalke) nur bei den beiden Wasserbecken in den Fluren. Auch die großen Säulen aus Muschelkalk zeigen, dass sie rasch und ohne weitere Qualitätsauswahl aus unterschiedlichen Muschelkalkschichten entnommen wurden, weshalb sie sowohl im als auch gegen das Lager übereinandergesetzt wurden, was bei derartigen Säulen steintechnisch nicht üblich ist. Der 1914 begonnene Bau des Instituts für Angewandte Chemie spiegelt seine besondere Bestimmung zur Förderung der Forschung im Zusammenhang mit dem ersten Weltkrieg eindrucksvoll wider. Der bis auf »heroische Figuren« über dem Eingangsbereich schnörkellose Bau zeigt die Vorherrschaft von Betonkunststein in der Fassade und in den großen Pfeilern im Treppenhaus. Die Elemente des vom Denkmalschutz besonders hervorgehobenen Holzzauns spannen sich zwischen mit grobem Beton überdeckte Backstein-Pfeilern, die heute besonders starke Schäden durch Abplatzen und Abschalen aufweisen. Der schmucklose Eingangsbereich leitet über zu einem ebenso schmucklosen Inneren mit überwiegend unterschiedlichen, einfarbigen Bodenfliesen und verschiedenen Kunststeinen. Nur die Eingangshalle ist mit dem für Bodenplatten besonders beliebten Solnhofener Kalkstein versehen. Ebenso sind nur der Gedenkstein an Prof. Max Busch, der damalige Rektor der Universität, und die Gedenktafel zur Würdigung der großzügigen Spender zur Errichtung des Baus in Treuchtlinger Kalkstein gefertigt wurden. Die Übergänge zwischen den verschiedenen Typen der Bodenfliesen sind abrupt und grenzen verschiedene Bereiche im Gebäude ab. Dazwischen wurde auch hier das damals hochmoderne Linoleum in großem Maße in unterschiedlichen Farben verwendet. Die großen Fenster aus Antikglas sind von besonderem Interesse. Hier wurde der Zweck des Baus in den verschiedenen Ornamenten in der Mitte der sechs Fenstereinheiten dokumentiert. Von der Erforschung der chemischen Elemente bis hin zu Düngemitteln und schließlich zum Sprengstoff wird der Einfluss der kriegswichtigen, praktischen Forschung deutlich. Die künstlerische Interpretation der hier schwerfälligen Rocaille-Ornamentik lässt keinen interpretatorischen Spielraum und ist wohl dem Wunsch des Auftraggebers angepasst, auf den sich der Künstler eingelassen hat. Glücklicherweise haben kriegsbedingte Schwierigkeiten dazu geführt, dass der Bau erst 1920 also etwa 2 Jahre nach dem Ende des ersten Weltkrieges bezogen werden konnte, und dadurch die kriegswichtigen Forschungsthemen anderen Schwerpunkten weichen mussten. Die Grundstücksgrenze zum heutigen Kitzmann-Areal stellt eine wertvolle, historisch verbürgte Grundstücksgrenze mit einem Teil der historischen Erlanger Stadtmauer dar, der auch bei heute eventuell anstehenden Baumaßnahmen nicht verändert werden darf. Das Direktionszimmer, das sich zentral in der zweiten Etage befindet, fällt aus dem Rahmen des nüchternen Zweckbaus. Hier wurde, wie im Direktionszimmer der Universitätsbibliothek, ein repräsentativer Raum mit einer Verkleidung und Wandschränken aus Eichenholz geschaffen. Dieser Raum wurde in den letzten Jahren als Bibliothek genutzt. Wie in der Universitätsbibliothek sollte das Ensemble des historischen Raumes unter Denkmalschutz gestellt werden

Description: DFG, SUB Göttingen

Description: research

Description: Aquatic environments have been anthropically influenced over the years, mainly with the construction of dams and hydroelectric plants. However, few studies evaluate how the parasitic fauna can be influenced in the long term by these environmental changes. Possible changes in the composition of endoparasites of the invasive fish Trachelyopterus galeatus in the upper Paraná River floodplain were investigated over a 27-year study period. 79 fish were analyzed in period 1 (1993) and 31 in period 2 (2019/2020). In the first period, the fish showed higher values in the variables weight (g) and standard length (cm), when compared to period 2. A total of five species of endoparasites were found, three per period. Although the richness was the same, the composition of endoparasites differed between the periods, as only one species of digenetic (Microrchis oligovitellum) parasitized the host in both periods of study. It was found that both the development of the fish and its endoparasites were affected over time. It is noteworthy that the beginning of operation of the Porto Primavera dam, located upstream of the plain, occurred between the two sampling periods (1999), and caused several environmental changes, possibly being the main responsible for these changes in the parasitofauna. Most endoparasites require intermediate hosts to complete their life cycles. Therefore, a modified environment may lose diversity and ecological interactions, as it affects the populations they use during the transmission process between hosts. This may explain the difference found in the infracommunities of T. galeatus parasites, emphasizing, through the results obtained, the importance of including these organisms in studies that evaluate environmental impacts caused by anthropic actions

Description: Ambientes aquáticos têm sido influenciado antropicamente ao longo dos anos, principalmente com a construção de barragens e usinas hidrelétricas. Contudo, poucos estudos avaliam como a fauna parasitária pode ser influenciada a longo prazo por essas mudanças ambientais. Investigou-se possíveis alterações na composição de endoparasitas do peixe invasor Trachelyopterus galeatus na planície de inundação do alto rio Paraná, em um intervalo de 27 anos de estudo. Foram analisados 79 peixes no período 1 (1993) e 31 no período 2 (2019/2020). No primeiro período, os peixes apresentaram maiores valores nas variáveis peso (g) e comprimento padrão (cm), quando comparados com o período 2. Encontrou-se um total de cinco espécies de endoparasitas, sendo três por período. Apesar da riqueza ter sido igual, a composição de endoparasitas diferiu entre os períodos, pois apenas uma espécie de digenético (Microrchis oligovitellum) parasitou o hospedeiro nos dois períodos de estudo. Constatou-se que tanto o desenvolvimento do peixe quanto seus endoparasitas foram afetados ao longo do tempo. Destaca-se que o início do funcionamento da barragem de Porto Primavera, localizada à montante da planície, ocorreu entre os dois períodos de amostragem (1999), e provocou diversas alterações ambientais, sendo, possivelmente, a principal responsável por essas mudanças da parasitofauna. A maioria dos endoparasitas requer hospedeiros intermediários para completar seus ciclos de vida. Portanto, um ambiente modificado, pode perder diversidade e interações ecológicas, visto que afeta as populações que eles utilizam durante o processo de transmissão entre hospedeiros. Isso pode explicar a diferença encontrada nas infracomunidades de parasitas de T. galeatus, enfatizando, por meio dos resultados obtidos, a importância de incluir esses organismos nos estudos que avaliam impactos ambientais causados por ações antrópicas.

Description: Masters

Description: Während der Corona-Pandemie schrieb der Schüler Pascal Schmitt mit Unterstützung des Vereins Wiechert'sche Erdbebenwarte Göttingen e.V.  im "Homeschooling" eine Facharbeit über die Auswertung seismischer Daten. Darin werden einige Daten eines Nah- und eines Fernbebens analysiert, die in Göttingen an der modernen Station GTTG (STS-2-Seismometer) und der historischen Station GTT (Wiechert-Seismographen) registriert wurden - nah und fern, neu und alt werden miteinander verglichen.

Description: DFG, SUB Göttingen

Description: research

Description: Aus Anlass des 100. Jahrestages der Gründung der Deutschen Geophysikalischen Gesellschaft im Jahre 1922 in Leipzig erschien 2019 im Verlag Edition am Gutenbergplatz Leipzig das Taschenbuch „Wiechert, Mintrop & Co. – Die 24 Gründungsväter der Deutschen Geophysikalischen Gesellschaft“ von Franz Jacobs und Michael Börngen (s. gleichlautenden Archivbeitrag in DGG-Mitteilungen, 1/2019: 36–37 sowie das anbei dargestellte Titelblatt des Buches). Die damalige Präsidentin und heutige Vize-Präsidentin der DGG, Heidrun Kopp, hat mit einem Geleitwort beigetragen. Das Buch kann über den Buchhandel unter ISBN 978-3-95922-107-8 bestellt werden. Der folgende Artikel erinnert an die Meteorologin Luise Lammert, Schriftführerin der Versammlung, auf der der Gründungsbeschluss gefasst wurde.

Description: DFG, SUB Göttingen

Description: research

Description: Leben und Werk des deutschen Geophysikers und Meteorologen Friedrich Bidlingmaier. In den Jahren 1901-03 nahm er als Physiker an der deutschen Südpolexpedition unter E. von Drygalski teil, dessen Ergebnisse zur Erforschung des Erdmagnetismus beitrugen. Er erfand den Doppelkompass zur Messung der horizontalen geomagnetischen Intensität. Cape Bidlingmaier an der Nordküste von Heard Island im südlichen Indischen Ozean trägt seinen Namen.

Description: research

Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 49(12), (2022): e2021GL097598, https://doi.org/10.1029/2021GL097598.

Description: The ocean is inhomogeneous in hydrographic properties with diverse water masses. Yet, how this inhomogeneity has evolved in a rapidly changing climate has not been investigated. Using multiple observational and reanalysis datasets, we show that the spatial standard deviation (SSD) of the global ocean has increased by 1.4 ± 0.1% in temperature and 1.5 ± 0.1% in salinity since 1960. A newly defined thermohaline inhomogeneity index, a holistic measure of both temperature and salinity changes, has increased by 2.4 ± 0.1%. Climate model simulations suggest that the observed ocean inhomogeneity increase is dominated by anthropogenic forcing and projected to accelerate by 200%–300% during 2015–2100. Geographically, the rapid upper-ocean warming at mid-to-low latitudes dominates the temperature inhomogeneity increase, while the increasing salinity inhomogeneity is mainly due to the amplified salinity contrast between the subtropical and subpolar latitudes.

Description: This work is supported by the Strategic Priority Research Program of Chinese Academy of Sciences (grant XDB42000000 and XDB40000000), the National Key R&D Program of China (2017YFA0603200), and the Shandong Provincial Natural Science Foundation (ZR2020JQ17), and the U.S. National Science Foundation Physical Oceanography Program (OCE- 2048336).

Description: 2022-12-23

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pirotta, E., Thomas, L., Costa, D., Hall, A., Harris, C., Harwood, J., Kraus, S., Miller, P., Moore, M., Photopoulou, T., Rolland, R., Schwacke, L., Simmons, S., Southall, B., & Tyack, P. Understanding the combined effects of multiple stressors: a new perspective on a longstanding challenge. Science of The Total Environment, 821, (2022): 153322, https://doi.org/10.1016/j.scitotenv.2022.153322.

Description: Wildlife populations and their habitats are exposed to an expanding diversity and intensity of stressors caused by human activities, within the broader context of natural processes and increasing pressure from climate change. Estimating how these multiple stressors affect individuals, populations, and ecosystems is thus of growing importance. However, their combined effects often cannot be predicted reliably from the individual effects of each stressor, and we lack the mechanistic understanding and analytical tools to predict their joint outcomes. We review the science of multiple stressors and present a conceptual framework that captures and reconciles the variety of existing approaches for assessing combined effects. Specifically, we show that all approaches lie along a spectrum, reflecting increasing assumptions about the mechanisms that regulate the action of single stressors and their combined effects. An emphasis on mechanisms improves analytical precision and predictive power but could introduce bias if the underlying assumptions are incorrect. A purely empirical approach has less risk of bias but requires adequate data on the effects of the full range of anticipated combinations of stressor types and magnitudes. We illustrate how this spectrum can be formalised into specific analytical methods, using an example of North Atlantic right whales feeding on limited prey resources while simultaneously being affected by entanglement in fishing gear. In practice, case-specific management needs and data availability will guide the exploration of the stressor combinations of interest and the selection of a suitable trade-off between precision and bias. We argue that the primary goal for adaptive management should be to identify the most practical and effective ways to remove or reduce specific combinations of stressors, bringing the risk of adverse impacts on populations and ecosystems below acceptable thresholds.

Description: This work was supported by the Office of Naval Research [grant numbers N000142012697, N000142112096]; and the Strategic Environmental Research and Development Program [grant numbers RC20-1097, RC20-7188, RC21-3091].

Description: Anlässlich des Arbeitstreffens der GeoUm im Rahmen des Bibliothekskongresses 2022 wurde eine kurze Bilanz für den FID GEO bis heute und ein Ausblick auf geplante Entwicklungen für die aktuell beantragte 3. Förderphase vorgetragen

Description: DFG, SUB Göttingen, GFZ Potsdam

Description: poster

Description: Die DFG-geförderten Fachinformationsdienste FID GEO, FID Karten und FID Montan unterstützen ihre jeweils eigene Fachcommunity und agieren zudem als gemeinsames Cluster für das System Erde. Im Zentrum stehen elektronisches Publizieren, Erwerbung und Digitalisierung von Spezialliteratur und Karten sowie die Unterstützung bei der Beschaffung von Geodaten und der Publikation von Forschungsdaten. Spezielle Rechercheinstrumente und in den Suchraum eingebundene fachspezifische Literaturnachweisdatenbanken bieten qualifizierten Zugang zu Informationen. Die hier vorgestellten Fachinformationsdienste kooperieren eng miteinander und ergänzen sich in ihren Angeboten für eine verbesserte Forschungsumgebung in der Erdsystemforschung im Sinne offener Wissenschaft. Das gemeinsame Ziel ist, aus dem FID-Cluster ein echtes Netzwerk zu knüpfen, welches interdisziplinär agiert und gleichermaßen fachspezifisch die Bedarfe der Wissenschaft bedient. Die drei Fachinformationsdienste werden einige ihrer Services kurz vorstellen, Beispiele einer kooperativen Zusammenarbeit und gemeinsame Herausforderungen präsentieren.

Description: DFG, SUB Göttingen,TU Bergakademie Freiberg, TU Berlin, GFZ Potsdam

Description: presentation

Description: In diesem Poster sollen die Möglichkeiten des offenen Publizierens in den Geowissenschaften, von der Probe über die Daten bis zum fertigen Manuskript und wie der FID GEO diesen Prozess begleitet, gezeigt werden. Hierbei liegt der Fokus auf den Services und Informationssystemen, die dauerhaft verfügbare und verlässlich zitierbare elektronische Publikationen von Schriften und Daten gewährleisten. Es soll das Potenzial und die Nutzbarkeit der beiden Repositorien vorgestellt werden. Der Service der Publikation von Schriften wird im Fachinformationsdienst-eigenem Fachrepositorium GEO-LEOe-docs bereitgestellt. Das fachspezifische Forschungsdaten Repositorium GFZ Data Services steht für die Veröffentlichung von Forschungsdaten und wissenschaftlicher Software aus den Erd- und Umweltwissenschaften zur Verfügung.

Description: DFG, SUB Göttingen, GFZ Potsdam

Description: poster

Description: Knowledge sharing in academia has been considered indispensable and is becoming a priority in most European funding schemes. Although we are already quite familiar with the different possibilities to publish our results in open-access journals, open science means way more than that. Open science aims at opening up research processes and granting access to research outputs to researchers, professionals and amateur scientists. There are different ways to ensure the storage and reusability of our data, making it available to other scientists. Furthermore, most of the scientific disciplines migrate their analyses to open-source environments (e.g., R, Phyton). However, tons of code produced remain stored in our personal computers either because we do not know the appropriate tools to share them with our colleagues or because we believe that it is not well structured. In this short course, you would learn how to establish links between publications, data, software and methods. Hence, we will discuss with our experts: i) the options to share our data and code with other peers, ii) obtain some tips to better organize our scripts, and iii) uncover potential barriers to sharing research and discuss possible solutions.

Description: DFG, SUB Göttingen, GFZ Potsdam

Description: presentation

Description: The rise of Open Science practices is impacting the entire scientific publishing culture. The transition to Open Access for text publications goes hand in hand with the growing demand to make scientific data and software available to the general public. The FAIR data principles play a key role in this, designed to make research and the underlying data easily findable, accessible, interoperable, and reusable for humans and machines. Geosciences data are as diverse as their content. They range from large real-time data streams of international observing networks to small data sets produced by individual researchers at their laboratories. Consequently, there need to be different strategies for data management and publication in which research data repositories can be important partners for the researchers. The Specialised Information Service for Geoscience (FID GEO) is a DFG-funded project that is promoting a holistic approach of Open Science that includes scholarly literature, data, samples, and scientific software equally and pushes for their interlinkage. FID GEO has become an important player for connecting researchers, data repositories, information infrastructures, German geoscientific societies, and publishers. FID GEO actively provides data and text publishing services through its affiliated repositories GFZ Data Services and GEO-LEOe-docs, as well as on-demand digitization of printed geoscience literature and maps. In addition, FID GEO aims to inform the German-based geoscience community about all aspects of Open Science and FAIR data by bringing the discussions to the individual disciplines through various communication channels.

Description: DFG, SUB Göttingen, GFZ Potsdam

Description: http://doi.org/10.5194/egusphere-egu22-13354

Description: presentation

Description: The rise of Open Science practices is impacting the entire scientific publishing culture. The transition to Open Access for text publications goes hand in hand with the growing demand to make scientific data and software available to the general public. The FAIR data principles play a key role in this, designed to make research and the underlying data easily findable, accessible, interoperable, and reusable for humans and machines. Geosciences data are as diverse as their content. They range from large real-time data streams of international observing networks to small data sets produced by individual researchers at their laboratories. Consequently, there need to be different strategies for data management and publication in which research data repositories can be important partners for the researchers. The Specialised Information Service for Geoscience (FID GEO) is a DFG-funded project that is promoting a holistic approach of Open Science that includes scholarly literature, data, samples, and scientific software equally and pushes for their interlinkage. FID GEO has become an important player for connecting researchers, data repositories, information infrastructures, German geoscientific societies, and publishers. FID GEO actively provides data and text publishing services through its affiliated repositories GFZ Data Services and GEO-LEOe-docs, as well as on-demand digitization of printed geoscience literature and maps. In addition, FID GEO aims to inform the German-based geoscience community about all aspects of Open Science and FAIR data by bringing the discussions to the individual disciplines through various communication channels.

Description: DFG, SUB Göttingen, GFZ Potsdam

Description: presentation

Description: FZ Data Services is a domain repository for geosciences data comprising the Earth, Space and Environmental Sciences. It assigns digital object identifier (DOI) to data and scientific software since 2004. Hosted at the GFZ German Research Centre for Geosciences (GFZ), the repository has a focus on the curation of long-tail data by domain scientists on one hand, but also provides DOI minting services for several global monitoring networks/observatories in geodesy and geophysics and collaborative projects. Furthermore, as Allocating Agent for the International Generic Sample Number (IGSN), the globally unique persistent identifier for physical samples, GFZ is providing IGSN minting services for physical samples. GFZ Data Services increases the interoperability of long-tail data through (1) the provision of comprehensive domain-specific data description via standardised and machine-readable metadata with controlled domain vocabularies. Metadata is (2) complemeted with comprehensive and standardised technical data descriptions or reports; and (3) by embedding the research data in wider context by providing cross-references through Persistent Identifiers (DOI, IGSN, ORCID, Fundref) to related research products (text, data, software) and people or institutions involved. In addition to the task as a research data publisher, GFZ Data Services is the central node for research data management at the GFZ with information on metadata, data formats, the data publication workflow, FAQ, links to different versions of our metadata editor and downloadable data description templates. Specific data publication guidance is complemented by more general information on data management, like a data management roadmap for PhD students.

Description: GFZ Potsdam

Description: presentation

Description: Die Fachinformationsdienste FID GEO, FID KARTEN und FID MONTAN veranstalteten eine gemeinsame Online-Session für die geowissenschaftlichen Fachreferate. Dabei wurden die einzelnen Fachinformationsdienste und ihre Services präsentiert und es wurde Gelegenheit geben, über zusätzliche Anforderungen an die Dienste aus Sicht der Fachreferate zu sprechen.

Description: DFG, SUB Göttingen

Description: presentation

Description: The shift towards Open Science practices is increasingly demanded by science policy. The transition to Open Access for text publications goes hand in hand with a growing demand to make data, scientific software and samples, freely and FAIRly available to the general public. A persistent problem here is the clear and permanent accessibility and re-usability of scientific publications. This development affects both the scientific publication culture as well as the information infrastructures and poses major challenges to the German- based geosciences community. The specialized information service for geosciences (FID GEO) is a service funded by the German Research Foundation (DFG) and supports the cultural change towards Open Access publications. Hereby, FID GEO pursues a holistic approach to Open Science, including scientific literature, data, samples, and scientific software, and aims to promote their interconnection. FID GEO actively provides data and text publishing services through the affiliated repositories GFZ Data Services and GEO-LEOe-docs, as well as an on-demand digitization service of printed geoscientific literature and maps. The focus here is on the services and information systems that ensure permanently available and reliably citable publications of writings and data. Specifically, the service for text publications is provided in the FID GEOs own subject repository GEO-LEOe- docs. The affiliated research data repository GFZ Data Services is available for the publication of research data and scientific software from the earth and environmental sciences. In addition, FID GEO aims to comprehensively inform the German-based geoscientific community about Open Science and FAIR data by bringing the discussions to the individual disciplines through various communication channels. To strengthen the open information culture in the geosciences, FID GEO collaborates with strategic (inter)national initiatives such as NFDI4Earth, COPDESS and OneGeochemistry.

Description: DFG, SUB Göttingen, GFZ Potsdam

Description: poster

Description: The Berlin Declaration from 2003 was the starting point for Open Access to scholarly publications. Today, however, we speak about Open Science that reaches far beyond Open Access and represents collaborative, transparent and accessible research that includes all kinds of research results: scholarly literature, research data, software, samples, instruments, etc. In addition, efforts such as the FAIR Principles and the Enabling FAIR Data Commitment Statement, combined with increasing demands for machine accessibility to data, have raised user expectations towards the capabilities of research data repositories and datacentres. These repositories are often key partners supporting researchers in fulfilling the new requirements. This presentation will draw the line from major statements and requirements of Open Science, delineate the role of research data repositories as well as major research infrastructures, like the fNFDI4Earth or EPOS (European Plate Observing System) are additional players in making research data accessible in harmonised form.

Description: DFG, SUB Göttingen, GFZ Potsdam

Description: presentation

Description: Als DFG-geförderter Service der Niedersächsischen Staats- und Universitätsbibliothek Göttingen (SUB) und des Deutschen GeoForschungsZentrums GFZ unterstützt der Fachinformationsdienst Geowissenschaften (FID GEO) den Wandel in der Forschungs- und Publikationskultur hin zu Open Science. Die freie Zugänglichkeit, aber auch Praktiken wie die korrekte Dokumentation und Verknüpfung verschiedener Forschungsbestandteile und Veröffentlichungsformate (Probenregistrierung, Datenpublikation, Texte, Karten, Software), stehen hier im Fokus. Der FID GEO bietet mit dem von der SUB Göttingen betriebenen Fachrepositorium GEO-LEOe-docs eine sachgerechte Open-Access-Publikation geowissenschaftlicher Werke an. Liegen diese nur gedruckt vor, übernimmt der FID GEO auch die unentgeltliche und professionelle Digitalisierung im Vorfeld der Online-Veröffentlichung. Seit 2021 ist die Telma auf der Startseite von GEO-LEOe-docs als fortlaufende Netzpublikation prominent hervorgehoben. Bereits seit 2018 erscheint sie parallel zum Druck als frei zugängliche Online-Publikation auf GEO-LEOe-docs. Ein großer Teil älterer TELMA-Artikel konnte digitalisiert und ebenfalls online gestellt werden. Die neueren Entwicklungen im FID GEO, darunter die Einbindung von ORCID und fortlaufenden Netzpublikationen im Repositorium, werden vorgestellt. Auch hat sich das jährliche DownloadVolumen von GEO-LEOe-docs in den letzten vier Jahren (2021 gegenüber 2017) verzehnfacht. Dass die Wissenschaft insgesamt besser vorankommt, wenn vorhergehende Forschungsergebnisse den Forschenden umfassender zugänglich sind, versteht sich. Doch auch für Autor*innen ist die frei zugängliche Publikation ihrer Ergebnisse im Open Access von Vorteil, da sie zu einer erhöhten Verbreitung der Veröffentlichungen führt, die folglich auch häufiger zitiert werden. Ebenso profitieren die Journale davon, da sich ihre Reichweite und damit die Beliebtheit der Zeitschrift erhöht. www.fidgeo.de https://e-docs.geo-leo.de/

Description: DFG, SUB Göttingen

Description: presentation

Description: How open is our research? A discussion on the state of Open Science in the field of mineralogy and petrology. Vortrag bei der Arbeitsgruppe Mineralogie+Petrologie der Uni Potsdam, 29.04.2022 A brief look at current trends toward an open science with a focused look at the state of the art in mineralogy and petrology. Followed by a discussion on how research in mineralogy and petrology can become more open.

Description: DFG, GFZ Potsdam

Description: presentation

Description: Author Posting. © American Meteorological Society, 2022. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 103(6), (2022): E1502-E1521, https://doi.org/10.1175/bams-d-21-0227.1.

Description: Climate observations inform about the past and present state of the climate system. They underpin climate science, feed into policies for adaptation and mitigation, and increase awareness of the impacts of climate change. The Global Climate Observing System (GCOS), a body of the World Meteorological Organization (WMO), assesses the maturity of the required observing system and gives guidance for its development. The Essential Climate Variables (ECVs) are central to GCOS, and the global community must monitor them with the highest standards in the form of Climate Data Records (CDR). Today, a single ECV—the sea ice ECV—encapsulates all aspects of the sea ice environment. In the early 1990s it was a single variable (sea ice concentration) but is today an umbrella for four variables (adding thickness, edge/extent, and drift). In this contribution, we argue that GCOS should from now on consider a set of seven ECVs (sea ice concentration, thickness, snow depth, surface temperature, surface albedo, age, and drift). These seven ECVs are critical and cost effective to monitor with existing satellite Earth observation capability. We advise against placing these new variables under the umbrella of the single sea ice ECV. To start a set of distinct ECVs is indeed critical to avoid adding to the suboptimal situation we experience today and to reconcile the sea ice variables with the practice in other ECV domains.

Description: PH’s contribution was funded under the Australian Government’s Antarctic Science Collaboration Initiative program, and contributes to Project 6 of the Australian Antarctic Program Partnership (ASCI000002). PH acknowledges support through the Australian Antarctic Science Projects 4496 and 4506, and the International Space Science Institute (Bern, Switzerland) project #405.

Description: 2022-12-01

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Owens, W., Zilberman, N., Johnson, K., Claustre, H., Scanderbeg, M., Wijffels, S., & Suga, T. OneArgo: a new paradigm for observing the global ocean. Marine Technology Society Journal, 56(3), (2022): 84–90, https://doi.org/10.4031/MTSJ.56.3.8.

Description: OneArgo is a major expansion of the Argo program, which has provided two decades of transformative physical data for the upper 2 km of the global ocean. The present Argo array will be expanded in three ways: (1) Global Core: the existing upper ocean measurements will be extended to high latitudes and marginal seas and with enhanced coverage in the tropics and western boundaries of the major ocean basins; (2) Deep: deep ocean measurements will be obtained for the 50% of the global oceans that are below 2,000-m depth; and (3) Biogeochemical: dissolved oxygen, pH, nitrate, chlorophyll, optical backscatter, and irradiance data will be collected to investigate biogeochemical variability of the upper ocean and the processes by which these cycles respond to a changing climate. The technology and infrastructure necessary for this expansion is now being developed through large-scale regional pilots to further refine the floats and sensors and to demonstrate the utility of these measurements. Further innovation is expected to improve the performance of the floats and sensors and to develop the analyses necessary to provide research-quality data. A fully global OneArgo should be operational within 5–10 years.

Description: In the United States, the National Science Foundation–funded Global Ocean Biogeochemistry Array (GO-BGC; https://go-bgc.org).

Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 36(1), (2022): e2021GB007113, https://doi.org/10.1029/2021GB007113.

Description: Stordalen Mire is a peatland in the discontinuous permafrost zone in arctic Sweden that exhibits a habitat gradient from permafrost palsa, to Sphagnum bog underlain by permafrost, to Eriophorum-dominated fully thawed fen. We used three independent approaches to evaluate the annual, multi-decadal, and millennial apparent carbon accumulation rates (aCAR) across this gradient: seven years of direct semi-continuous measurement of CO2 and CH4 exchange, and 21 core profiles for 210Pb and 14C peat dating. Year-round chamber measurements indicated net carbon balance of −13 ± 8, −49 ± 15, and −91 ± 43 g C m−2 y−1 for the years 2012–2018 in palsa, bog, and fen, respectively. Methane emission offset 2%, 7%, and 17% of the CO2 uptake rate across this gradient. Recent aCAR indicates higher C accumulation rates in surface peats in the palsa and bog compared to current CO2 fluxes, but these assessments are more similar in the fen. aCAR increased from low millennial-scale levels (17–29 g C m−2 y−1) to moderate aCAR of the past century (72–81 g C m−2 y−1) to higher recent aCAR of 90–147 g C m−2 y−1. Recent permafrost collapse, greater inundation and vegetation response has made the landscape a stronger CO2 sink, but this CO2 sink is increasingly offset by rising CH4 emissions, dominated by modern carbon as determined by 14C. The higher CH4 emissions result in higher net CO2-equivalent emissions, indicating that radiative forcing of this mire and similar permafrost ecosystems will exert a warming influence on future climate.

Description: We would like to acknowledge the following funding in support of this project: Swedish Research Council (Vetenskapsrådet, VR) grants (NT 2007-4547 and NT 2013-5562 to P. Crill), U.S. Department of Energy grants (DE-SC0004632 and DE-SC0010580 to V. Rich and S. Saleska), and U.S. National Science Foundation MacroSystems Biology grant (NSF EF #1241037, PI Varner). This work was supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research under the Genomic Science program. We also acknowledge funding from the National Science Foundation for the EMERGE Biology Integration Institute, NSF Award #2022070.

Description: 2022-07-03

Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 127(1), (2022): e2021JC017424, https://doi.org/10.1029/2021JC017424.

Description: By compiling boreal summer (June to October) CO2 measurements from 1989 to 2019 on the Bering and eastern Chukchi Sea shelves, we find that the study areas act as a CO2 sink except when impacted by river runoff and wind-driven upwelling. The CO2 system in this area is seasonally dominated by the biological pump especially in the northern Bering Sea and near Hanna Shoal, while wind-driven upwelling of CO2-rich bottom water can cause episodic outgassing. Seasonal surface ΔfCO2 (oceanic fCO2 – air fCO2) is dominantly driven by temperature only during periods of weak CO2 outgassing in shallow nearshore areas. However, after comparing the mean summer ΔfCO2 during the periods of 1989–2013 and 2014–2019, we suggest that temperature does drive long-term, multi-decadal patterns in ΔfCO2. In the northern Chukchi Sea, rapid warming concurrent with reduced seasonal sea-ice persistence caused the regional summer CO2 sink to decrease. By contrast, increasing primary productivity caused the regional summer CO2 sink on the Bering Sea shelf to increase over time. While additional time series are needed to confirm the seasonal and annual trajectory of CO2 changes and ocean acidification in these dynamic and spatially complex ecosystems, this study provides a meaningful mechanistic analysis of recent changes in inorganic carbonate chemistry. As high-resolution time series of inorganic carbonate parameters lengthen and short-term variations are better constrained in the coming decades, we will have stronger confidence in assessing the mechanisms contributing to long-term changes in the source/sink status of regional sub-Arctic seas.

Description: We gratefully acknowledge the support of the funding agencies that supported this analysis, including the New Sustained Observations for Arctic Research project and the DBO-NCIS project (NA14OAR4320158, NA19OAR4320074) from the NOAA Arctic Research Program.

Description: 2022-06-17

Description: Das Ziel des COSC-2 (Collisonal Orogeny in the Scandinavian Caledonides) Projektes ist es, die Entstehungsprozesse der Skanden zu untersuchen. Hierfür sind Kenntnisse über die Deformationen / Faltungsprozesse von großer Wichtigkeit, die sich aus der Richtung der remanenten Magnetisierung ableiten lassen. Die teufenabhängigen Magnetisierungsvektoren lassen sich aus dreikomponetigen Bohrlochmagnetikdaten berechnen. Als Datengrundlage dienen Messungen, die mit einem Dipmeter in der COSC2-Bohrung in Järpen (Schweden) durchgeführt wurden. Es wurden 5 Messungen mit 1cm Messpunktabstand in verschiedenen Teufenbereichen zwischen 100m und 2250m Teufe aufgezeichnet. Anhand der in der Sonde verbauten Accelerometer und dem bekannten Verlauf der Bohrung konnten die Magnetfelddaten in das geographische Referenzsystem reorientiert werden. Die erreichte Genauigkeit beträgt 1,5° in der Deklination und 0,16° in der Inklination. Um die Magnetisierung der durchbohrten Gesteinseinheiten zu bestimmen wird an die reorientierten Magnetfelddaten ein Schichtmodell nach Bosum et al (1988) angepasst. Dieses Modell nähert die Schichten durch zentral durchbohrte Zylinder. Das Modell von Bosum geht von einem Zylinder aus, der senkrecht zu den Deckflächen zentral durchbohrt wird. In der COSC-2 Bohrung ist aber zum einen das Bohrloch geneigt, zum anderen weisen auch die durchbohrten Schichten eine Neigung auf. Aus diesem Grund erweitern wir das Bosum-Modell nach Ehmann (2016) für beliebige Schichtinklinationen. Die Schichtmächtigkeiten werden durch die Lithologie der Bohrung bestimmt, die aus den Bohrkernen abgeleitet wurde. Eine erste Analyse zeigt, dass in den oberen 1200m der Bohrung nur schwach magnetisierte Gesteine vorherrschen. Darunter folgen stärker magnetisierte-Schichten, die im Mittel eine Magnetisierung von 1A/m aufweisen. Im Bereich von 1590m bis 1850m befindet sich eine stark magnetisierte Sektion, die sich in vier Bereiche aufteilen lässt. Die Magnetisierung in dieser Sektion beträgt bis zu 5 A/m. In der stark magnetisierten Sektion können zwei Bereiche identifiziert werden, in denen die Inklination der Magnetisierungen von 40° auf bis zu 80° ansteigt. Die beiden Bereiche mit hoher Inklination weichen in ihrer Deklination von der mittleren Deklination der Sektion um +90° und -90° ab. Diese Variationen deuten auf Deformationen der Gesteinsschichten hin. Unterhalb dieser Sektion schließt sich eine Sektion mit Magnetisierungen von etwa 1 A/m und Inklinationen von etwa 15° an.

Description: DFG, Fördernummer VI 836/5-1

Description: poster

Description: Der Hessische Erdbebenkatalog ist eine Zusammenstellung historischer und aktueller Informationen zu Erdbeben in Hessen und direkter Umgebung von Hessen. Er wird vom Hessischen Erdbebendienst geführt und regelmäßig aktualisiert. Eine 50 km-Umhüllende wurde um Hessen herum gelegt, um auch Erdbeben und die dazugehörenden Bereiche zu betrachten, die Auswirkungen auf Hessen haben können. Eine Vollständigkeit wird jedoch nur für das Gebiet des Landes Hessen angestrebt. Für den seismischen Katalog Hessen (SKHe2022) wurden verschiedene, verfügbare Erdbebenkataloge und Ausarbeitungen zu Grunde gelegt. Des Weiteren beinhaltet der Katalog Ereignisse aus mehreren wissenschaftlichen Publikationen. Das Stichdatum für den Katalog ist der 31.12.2021. Der Erdbebenkatalog Hessen wird auch in Zukunft fortgeschrieben und ist damit als Zwischenstand zu sehen. In Zukunft wird er halbjährig aktualisiert und der Öffentlichkeit über den Geologie-Viewer des Hessischen Landesamtes für Naturschutz, Umwelt und Geologie unter geologie.hessen.de zur Verfügung gestellt. Im seismischen Katalog Hessen werden fünf Zeiträume beschrieben. Dabei handelt es sich für den Zeitraum 800 bis 1700 um Daten, die aus Chroniken ermittelt wurden. Für den Zeitraum 1701 bis 1950 beruhen viele der älteren Ereignisse auf makroseismischen Daten. Durch den aufkommenden Zeitungsdruck wurden wesentlich mehr Daten erhoben als in dem Zeitraum davor. Seit Anfang des 20. Jahrhunderts wurden dann auch Erdbeben instrumentell aufgezeichnet. Das analog-instrumentelle Zeitalter wird für den Zeitraum 1951 bis 1975 angegeben. Das digital-instrumentelle Zeitalter gilt ab 1976. Es wurde eine Priorisierung der einzelnen Erdbebenereignisse, wenn mehrere Ereignisse von unterschiedlichen Quellen aufgezeichnet wurden, durchgeführt. In der aktuellen Version sind sämtliche bekannte induzierte Ereignisse identifiziert worden. In der veröffentlichten Version sind diese induzierten Ereignisse nicht mehr enthalten, so dass der Erdbebenkatalog des Landes Hessen als rein tektonischer, auf natürlichen Erdbeben basierender, Erdbebenkatalog angesehen werden kann. Die stärksten historischen Erdbeben traten in den Jahren 858, 1733 und 1858 in Mainz, 1619 im südlichen Taunus, 1767 in Rothenburg/Fulda, sowie als Erdbebenschwarm in Groß-Gerau (1869-1871), 1871 in Lorsch und im Odenwald auf. Das stärkste Erdbeben in den letzten Jahren fand im Jahr 2014 bei Ober-Ramstadt im Odenwald mit einer Magnitude von 4,2 statt.

Description: poster

Description: Aeromagnetic surveys help us to learn about geology. To achieve good coverage, surveys need to be merged. However, conventional methods introduce long-wavelength bias and cannot handle the individual survey quality. We develop a new approach to process large aeromagnetic surveys with an equivalent layer approach and combine them with satellite data. To facilitate the usage of large data sets, we divide the study area into blocks and treat each block individually. We adjust the block size according to the resolution of the equivalent source model. Within each block we solve for equivalent sources using an iterative linear inversion with Tikhonov regularization. We apply a multi-resolution strategy by iteratively decreasing the dipole spacing, dipole depth and block size. In each step, the resolution is applied to the residual of the previous steps. This ensures both a good representation of the large and small-scale structures as well as reasonable computational costs. Advantages of the blockwise inversion are the handling with large data sets due to splitting up the study area and neglecting influences of sources above a certain distance. This reduces computational costs and still fits the data well in comparison with an unblocked inversion. Some structures cannot be resolved well with just one dipole layer, so the multi-resolution strategy enables to have a better fit by separating regional and local sources. For the final compilation, we replace the long wavelengths part of the aeromagnetic data with satellite data to spherical harmonic degree 110. We demonstrate our new approach with a newly compiled large data base for Greenland.

Description: poster

Description: In Folge des Klimawandels kommt es in Mitteleuropa vermehrt zu Dürreperioden und Austrocknung von Böden. Indem tief- und flachwurzelnde Nutzpflanzen sinnvoll kombiniert werden, kann die Verfügbarkeit von Wasser teils auch ohne künstliche Bewässerungsmaßnahmen verbessert werden. Die Tiefwurzler erschließen tiefer gelegenes Wasser und können es so umverteilen (‚hydraulische Umverteilung‘), dass auch benachbarte Flachwurzler mit Wasser versorgt werden. Mit dem Ziel eine solche Umverteilung von Wasser durch Pflanzen mithilfe geoelektrischer Methoden zu untersuchen, wurde in dieser Studie ein Versuchsaufbau entwickelt und getestet. Auf 23 Feldern wurden verschiedene Kombinationen der Pflanzen beobachtet. Dafür wurden sowohl Oberflächenmessungen mittels Gleichstromgeoelektrik, als auch Bohrlochmessungen mittels Spektraler Induzierter Polarisation (SIP) durchgeführt. Die Ergebnisse wurden mit konventionellen Bodenfeuchtemessgeräten (time domain reflectometry, TDR) verglichen, welche die Bodenfeuchte nur punktuell erfassen können. Für die Bohrlochmessungen wurde ein experimenteller Aufbau zur Beobachtung der räumlichen Verteilung des Wassers im Untergrund umgesetzt. Um eine hohe Auflösung im Bereich der flachen Wurzeln zu erreichen, wurde ein bohrlochartiges System genutzt. Dieses besteht aus metallischen Ringelektroden, die an einem Holzstab befestigt sind, der senkrecht in den Boden eingebracht wird. Die Elektroden haben dabei nahe der Oberfläche die kleinsten Abstände (5cm), da in diesem Bereich die Wurzeln der Tief- und Flachwurzler gemeinsam vorkommen. Hier soll die Auflösung möglichst hoch sein, damit die Wasserumverteilung gut beobachtet werden kann. Mit zunehmender Tiefe nehmen die Elektrodenabstände zu. Hier ist eine geringere Auflösung ausreichend, da nur die Tiefwurzler Wasser aufnehmen. Da die Stäbe bereits vor dem Sähen der Pflanzen in den Boden gebracht wurden, war ein Monitoring über mehrere Monate möglich: Zur Aussaat der Pflanzen Ende März, während des Wachstums und im September während eines finalen Bewässerungsexperimentes. Die bisherigen Auswertungen der Ergebnisse zeigen, dass sich die zeitliche Entwicklung der Bodenfeuchte anhand der geoelektrischen Daten gut nachvollziehen lässt und im Gegensatz zu den TDR-Daten auch die räumliche Verteilung hoch aufgelöst (〈5cm) erfasst werden kann. Die Oberflächenmessungen zeigen, dass die Schichtung des Bodens über die Plots variiert, was sich auf die Vergleichbarkeit der Ergebnisse auswirken kann.

Description: poster

Description: Recent years have shown an increased interest in Polar research and in particular in understanding tectonics and seismic hazard in the Arctic. To understand the seismic activity in the European Arctic, the seismic bulletins should be as complete as possible. We present a new seismic event bulletin for the European Arctic (70° – 90° N, -15° – 75° E), for the 24-year long period 1990 – 2013. The poster will show in detail the merging of the different sources taken in account for the compilation, the homogenization of the data and the relocation of the seismic events. With respect to the ISC bulletin for this region, the new bulletin contains 5,932 new seismic events and 54,630 new seismic onset readings from stations mostly located at regional distances. The gains are distributed over the entire study region, with the most significant contributions across the Svalbard Archipelago, along the Knipovich and northern Mohns Ridges, as well as northern Fennoscandia.

Description: Norwegian Research Council Grant 233973/H30

Description: Russian Foundation for Basic Research Grant 14-05-93080

Description: Russian Foundation for Basic Research Grant 18-05-70018

Description: https://doi.org/10.31905/TYLLQY8T

Description: poster

Description: During the last few years, the use of Ground-Penetrating-Radar (GPR) multi-channel antenna arrays in the Archaeological Prospection increased dramatically. The main advantage of this type of survey is a much faster data acquisition combined with a dense profile spacing. However, most of the common multi-channel arrays consist of antennae with a spacing of not smaller than 8 cm. The aim of our test survey was to evaluate how an even denser spacing of 4 cm that is provided by the IDS Stream-C GPR device at a centre frequency of 600 MHz can improve the detection of small archaeological features. As a test site, we chose the Great Bath in Kempten-Cambodunum. This first capital of the Roman province Rhaetia never has been overbuilt in the following centuries and even today it is used as a grassland declared as an Archaeological Park. Already in 1911, the Great Bath was excavated and beside the walls of different building phases, also small features like a multitude of hypocaust pillars were unearthed. Hence, this building structure depicts an ideal test site and a 40x40m grid covering the main part of the construction was chosen for the application of the antenna array. As a comparison, the same grid was contemporaneously surveyed with a single antenna IDS Duo device (600 and 200 MHz) and a 50 cm profile spacing. Regarding the walls of the Roman bath, the two surveys show comparable results: both datasets represent the stone constructions of 50 – 90 cm width quite well. Furthermore, the depth slices of both devices provide a differentiation of the single building phases. Nevertheless, the resolution for the multi-channel antenna array is of course much higher due to the denser profile spacing. Huger differences occur for the hypocaust pillars of 25 cm lateral length. These features can be mapped in detail with the 4 cm profile spacing of the IDS Stream-C system. Whereas the IDS Duo can only resolve some of the hypocausts, a multitude of them gets visible between 70 and 110 cm depth in the Stream-C data. As a conclusion, it can be stated that standard archaeological remains like stone walls, for sure, can be surveyed with single antenna GPR devices in a common profile spacing of 50 cm. However, in case of the existence of faint archaeological features the application of ultra-dense antenna arrays like the IDS Stream-C is advisable to get a comprehensive overview of a site without the necessity to excavate them.

Description: poster

Description: Mit dem zerstörungsfreien Verfahren der nuklear magnetischen Resonanz (NMR) mit Fokus auf 1H-Protonen lässt sich der Feuchtegehalt in porösen Materialien bestimmen und bei einem vollgesättigten Medium eine Porengrößenverteilung ableiten. Für die Ermittlung der Porengrößenverteilung muss die gemessene T2-Relaxationszeitenverteilung mit dem Parameter Oberflächenrelaxivität (OR) umgerechnet werden. Ist dieser Parameter für das zu untersuchende Medium unbekannt, kann dieser mithilfe von Vergleichsverfahren abgeschätzt werden. Dabei kommen z. B. Gassorption, Quecksilberporosimetrie (MIP), Dünnschliff-Mikroskopie oder µ-Computer-Tomographie (µ-CT) zum Einsatz. Da die verschiedenen Verfahren allerdings unterschiedliche Auflösungsgrenzen aufweisen und auf verschiedenen physikalischen Prinzipien beruhen, können die ermittelten ORs für ein Medium stark variieren. Um ein besseres Verständnis für die OR und die Einflüsse der Vergleichsverfahren zu bekommen, wurden 19 verschiedene Sandsteintypen untersucht. Die OR wurde zum einen basierend auf der spezifischen inneren Oberfläche aus der dynamischen Dampfsorption (DVS) und der Gassorption abgeleitet. Zum anderen wurden die Relaxationszeitenverteilungen durch manuelles Anpassen der OR derart in Porengrößenverteilungen umgerechnet, sodass es eine Übereinstimmung mit den Porengrößenverteilungen aus MIP und/oder µ-CT gibt. Die Umrechnung von Relaxationszeitverteilungen in eine Porengrößenverteilung berücksichtigt dabei sowohl fast- als auch slow-diffusion. Insgesamt ergab sich für die Sandsteine ein breites Spektrum an ORs, bei dem die über die innere spezifische Oberfläche ermittelten ORs andere Größenordnungen aufwiesen (〈 10 µm/s), als bei dem Vergleich mit MIP oder µ-CT (bis 600 µm/s). Die mit MIP und µ-CT ermittelten Werten lagen dabei um einen Faktor von 1 bis 30 auseinander. Dieser umfangreiche Datensatz, der vier verschiedene Vergleichsverfahren einbezieht, soll neue Erkenntnisse in der Charakterisierung von porösen Materialien (z. B. bezüglich der Oberflächenrauigkeit) und in der Ursache für die starke Variation der OR ermöglichen. Durch das Berücksichtigen von fast- als auch slow-diffusion, können dabei sogar Daten in eine Porengrößenverteilung umgerechnet werden, bei denen das fast-diffusion-Kriterium nach Brownstein und Tarr nicht erfüllt ist. Außerdem ergibt sich aus der Berücksichtigung des slow-diffusion-Regimes ein neues Verständnis für die obere Auflösungsgrenze von NMR.

Description: poster

Description: Das Poster präsentiert die Ergebnisse des kombinierten Einsatzes von NMR und LIBS zur Verfolgung von Feuchtigkeit und Schadionen in Baustoffen. Es wurden dazu mit zwei Sandsteine und zwei zementäre Baustoffe kapillare Saugversuche durchgeführt. Die Materialien wurden 5 mm tief in Natriumchloridlösungen einer Konzentration von 1 mol/l und 4 mol/l getaucht. Mit NMR wurde der Feuchteanstieg, mit LIBS der Chloridionenanstieg ermittelt. Ergebnisse sind unter anderem, dass die Feuchte den Ionen immer vorauseilt. Außerdem ist die Anstiegsgeschwindigkeit direkt abhängig vom Porensystem und von der Lösungskonzentration.

Description: poster

Description: The Floodrisk project takes a muti- and interdisciplinary look on the effects of the rise in mine water level in abandoned coal mine regions in Germany. Such effects are heterogeneous ground uplift, stress changes due to the pore pressure changes and the reactivation potential of faults. One of the most directly measurable effects is the induced seismicity. It is known from previous studies that the flooding of old mines can lead to a renewed increase in induced microseismicity in these regions. We focused on the observation of the eastern Ruhr area and investigate in detail the relationship between mine water rise and induced seismicity in the Haus Aden dewatering area. For this purpose, we operate a network of up to 30 short period seismic stations in the region of the former "Bergwerk Ost" colliery, which had the highest seismicity rate in the Ruhr area during active mining. Continuous monitoring of seismicity and mine water levels is available for this region from the active mining phase, through the post-mining phase to flooding. Since the beginning of the flooding, more than 20000 onsets were picked and over 1700 induced events were localised in a magnitude range from -0.7 up to 2.6 MLv. For some larger events, focal mechanisms could be determined. The spatial distribution of hypocentres is divided into two areas, with few events in the central study area and over 95% of earthquakes in its eastern part. Many of these events are spatially clustered and some show quite high waveform similarity. This allows relative localisation to increase the accuracy of the location. Comparing the old galleries,which today serve as the main underground waterways, with the localisations from the relative localisation, strong correlations can be seen. The measured temporal trend of the mine water level, after pumps were shut down in mid-2019, shows a strong correlation with the temporal evolution of the observed micro seismicity. In the first months after the pumps are switched off, the water levels at the observation points rise only slowly and isolated microseismic events occur again. In November 2019, the rise in water levels doubled and at the same time, the strongest induced event in the measurement period was recorded with a magnitude of 2.6 MLv. In the years 2020, 2021 66 and 58 events 〉= MLv 1 were observed, respectively. In contrast to this number only 2- 9 events 〉= MLv 1 per year were observed in the post-minig phase before flooding.

Description: Bundesministerium für Bildung und Forschung

Description: poster

Description: In the last few years, several Unmanned Aerial Vehicle (UAV) based magnetometer systems have been tested for archaeological prospection. Due to their higher sensitivity, scalar magnetometers have been preferred as test sensors. However, total field magnetometer are vulnerable to disturbances, especially those generated by the UAV itself. Therefore, most UAV scalar magnetometer systems use the method of increasing the distance between magnetic sensors and the UAV to reduce interference. But freely suspended sensors tend to swing on ropes under the UAV and can produce data that are strongly influenced by heading errors. For our test, we therefore chose the UAV-fixed, compact setup of the SENSYS MagDrone R4, which is equipped with five three-axis FGM3D/75 fluxgate sensors at 50 cm spacing and is covering a swath width of 2.5 m. The 200Hz sampling rate of the R4 allows easy filtering of interference generated by the UAV and external disturbances like power lines or infrastructure. Magnetograms with a spatial resolution of up to 0.20 m per pixel were produced from the data. At Ganacker, we chose the former infrastructure core of the World War II German Air Force airfield as a test site. A wide range of archaeological structures and features with high magnetic contrast were expected on this area. The test site is currently an open agricultural area with a quite flat terrain. Hence, the R4 could be operated at a fixed flight height of just one metre above the surface of the terrain that is controlled actively by a radar sensor. An area of around 110 hectares were prospected within only four days. The MagDrone R4 system thus offers an outstanding survey area progress that cannot even reached by common vehicle-moved multi-sensor arrays. Here, we present the first results of this test survey by comparing the magnetograms, historical and current geodata. Most of the expected archaeological features and several unknown ones were detected by the R4 system. Our results show that the R4 system is well suited for mapping large archaeological structures with high magnetisations. In the future, we want to compare the R4 data with data from a ground-based fluxgate magnetometer. We also want to test whether the system is suitable for detecting archaeological features that have lower magnetic susceptibility and remanence contrasts with the surrounding soil.

Description: poster

Description: Geological maps are complex to produce through intensive and expensive field studies. Comparisons of geophysical data with geological conditions are difficult and often only qualitatively possible. The following work therefore examines an automated procedure to better reconcile this information. For this purpose, the terracing method, and a cluster analysis of potential field (gravity and magnetic field) and petrophysical data from the Karasjok and Ligurian Sea regions are used to interpret this geophysical measurements in a geological way. Two different tectonic regions were selected: (1) The Karasjok region is located in Northern Norway, where the Karasjok Greenstone Belt (KGB) dominates geological settings, consisting of abundant ultramafic intrusions, komatiites, gabbroic intrusions, amphibolites and migmatites. (2) The Ligurian-Provençal basin, part of the Western Mediterranean Sea, which is located between the French-Italian coastline and the island of Corsica. Geologically the area is characterised by the spreading zone in the Western Mediterranean. The high-resolution Airborne Gravity Gradient Survey and aeromagnetic datasets of the Karasjok region cover an area of 20 km x 30 km with a data resolution of 50 m. The dataset of the Ligurian basin cover a much larger area with the resolution of 5 km. Data constraints come from former LOBSTER and LISA campaigns and a study in the research group at CAU Kiel, new compilation of the AlpArray Gravity Research Group (AAGRG), besides data of the ICGEM Potsdam (disturbance) and the GOCE mission. By aid of the terracing algorithm, the boundaries of the anomalies are to be sharpened and regions with constant field amplitude were generated. For this purpose, a shape index-based algorithm was applied, which uses the shape index calculated at each field point to grade the function. Through an iterative process and the variation of parameters, the terracing result is refined. The resulting data sets are then further processed using a cluster analysis method. Here, the k-mean algorithm for domain classification is used to divide the geophysical measurement data into groups (cluster) of similar properties. The number of clusters k is specified and the data points are assigned to the respective clusters through an iterative process. Using the data of the datasets mentioned above the results of this applications are successfully compared with the corresponding geological maps of the two areas.

Description: Deutsche Forschungsgemeinschaft (DFG), SPP "MB-4D"

Description: https://doi.org/10.5880/fidgeo.2020.045 (Zahorec et al., 2021) via GFZ Data Services

Description: poster

Description: Aquatic macrophytes are macroscopic photosynthetic organisms that encompass several taxonomic groups of plants, with broad limnological characteristics that colonize from marshes to submerged areas, playing a fundamental role in structuring wetlands and affecting aquatic biodiversity. The Neotropical Region, covering from the south of Mexico to the south of Argentina, is characterized for being one of the most biodiverse regions in the world, with a unique biota, many endemic species and a great diversity of environments. As one of the wetlands with the greatest potential in this ecozone and the world, the Paraná-Paraguay basins stand out. The objectives of this thesis were to quantify and qualify the species of aquatic macrophytes that occur in the Neotropical Region and in the Paraná-Paraguay basins, carry out an analysis of hotspots for the Paraná-Paraguay basins and provide current information and indicators of areas of high richness of aquatic macrophytes. A conservation efficiency analysis is also available that correlates areas considered hotspots and the protected areas present in these basins. Data from systematic searches in important bibliographic bases were used to compose the lists and geographic coordinates. A total of 1616 spp. for the Neotropics and 979 species for the Paraná-Paraguay basins. The families with the highest number of species were Cyperaceae Juss. and Poaceae Barnhart in both regions studied. Species richness for the Paraná-Paraguay basins was recorded using occurrence points, with 5 locations with values from 71 to 139 species and 50 locations from 1 to 11 species, with the Lower Paraná River having the lowest number of occurrences and the Lower Paraguay River the largest amount. Sixteen sub-basins considered as hotspots were registered, and these areas coincided with the areas of greatest richness. Approximately 6% of the total ecological hotspot areas are being conserved within protected areas. In conclusion, the results obtained in both surveys reaffirm the high number of species present in these wetlands, highlighting the need for further systematic and taxonomic studies of aquatic macrophytes, seeking to precisely detail these megadiverse regions.

Description: Macrófitas aquáticas são organismos fotossintetizantes macroscópicos que englobam vários grupos taxonômicos de plantas, com amplas características limnológicas que colonizam desde brejos até áreas submersas,desempenhando papel fundamental na estruturação das áreas úmidas e afetando a biodiversidade aquática. A Região Neotropical, abrange desde o sul do México até o sul da Argentina, caracteriza-se por ser uma das regiões mais biodiversas do mundo, com biota singular, grande número de espécies endêmicas e grande diversidade de ambientes. Como uma das áreas úmidas de maior potencial desta ecozona e do globo, destacam-se as bacias Paraná-Paraguai. Os objetivos dessa tese foram quantificar e qualificar as espécies de macrófitas aquáticas ocorrentes na Região Neotropical e nas bacias Paraná-Paraguai,efetuar análise de hotspots para as bacias Paraná-Paraguai e disponibilizar informações atuais e indicadoras de áreas de alta riqueza de macrófitas aquáticas. Também é disponibilizado uma análise de eficiência de conservação que correlaciona áreas consideradas hotspots e as áreas protegidas presentes nessas bacias. Dados de buscas sistemáticas em importantes bases bibliográficas foram utilizados para compor as listas e coordenadas geográficas. Registrou-se um total de 1616 spp. para os Neotrópicos e 979 espécies para as bacias Paraná-Paraguai. As famílias com maior número de espécies foram Cyperaceae Juss. e Poaceae Barnhart em ambas as regiões estudadas. A riqueza de espécies para as bacias Paraná-Paraguai foi registrada por meio de pontos de ocorrência, apresentando 5 locais com valores de 71 a 139 espécies e 50 locais de 1 a 11 espécies, sendo o Baixo Rio Paraná com a menor quantidade de ocorrências e o Baixo Rio Paraguai a maior quantia. Foram registradas 16 sub-bacias consideradas hotspots, e estas áreas coincidiram com as áreas de maior riqueza. Aproximadamente 6% do total das áreas de hotspots ecológicos estão sendo conservados dentro de áreas protegidas. Em conclusão, os resultados obtidos em ambas as pesquisas reafirmam o alto número de espécies presentes nessas áreas úmidas, deixando evidente a necessidade de mais estudos sistemáticos e taxonômicos para macrófitas aquáticas, em busca de detalhar precisamente essas regiões megadiversas.

Description: PhD