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  • Articles  (27)
  • Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.  (15)
  • Cambridge University Press
  • 2020-2024  (5)
  • 2020-2023  (22)
  • 1950-1954
  • 2020  (27)
  • 2020  (27)
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  • 2020-2024  (5)
  • 2020-2023  (22)
  • 1950-1954
  • 2020-2022  (1,975)
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  • 1
    Publication Date: 2022-10-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Roberts, Mark L., Elder, Kathryn L., Jenkins, William J., Gagnon, Alan R., Xu, Li, Hlavenka, Joshua D., & Longworth, Brett E. C-14 Blank Corrections for 25-100 mu G samples at the National Ocean Sciences AMS Laboratory. Radiocarbon, 61(5), (2019): 1403-1411, Doi: 10.1017/RDC.2019.74.
    Description: Replicate radiocarbon (14C) measurements of organic and inorganic control samples, with known Fraction Modern values in the range Fm = 0–1.5 and mass range 6 μg–2 mg carbon, are used to determine both the mass and radiocarbon content of the blank carbon introduced during sample processing and measurement in our laboratory. These data are used to model, separately for organic and inorganic samples, the blank contribution and subsequently “blank correct” measured unknowns in the mass range 25–100 μg. Data, formulas, and an assessment of the precision and accuracy of the blank correction are presented.
    Description: This work is supported by a Cooperative Agreement (OCE-1755125) with the U.S. National Science Foundation.
    Keywords: AMS ; AMS dating ; Blank corrections
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 2
    Publication Date: 2022-10-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Baker, M. G., Aster, R. C., Anthony, R. E., Chaput, J., Wiens, D. A., Nyblade, A., Bromirski, P. D., Gerstoft, P., & Stephen, R. A. Seasonal and spatial variations in the ocean-coupled ambient wavefield of the Ross Ice Shelf. Journal of Glaciology, 65(254), (2019): 912-925, doi:10.1017/jog.2019.64.
    Description: The Ross Ice Shelf (RIS) is host to a broadband, multimode seismic wavefield that is excited in response to atmospheric, oceanic and solid Earth source processes. A 34-station broadband seismographic network installed on the RIS from late 2014 through early 2017 produced continuous vibrational observations of Earth's largest ice shelf at both floating and grounded locations. We characterize temporal and spatial variations in broadband ambient wavefield power, with a focus on period bands associated with primary (10–20 s) and secondary (5–10 s) microseism signals, and an oceanic source process near the ice front (0.4–4.0 s). Horizontal component signals on floating stations overwhelmingly reflect oceanic excitations year-round due to near-complete isolation from solid Earth shear waves. The spectrum at all periods is shown to be strongly modulated by the concentration of sea ice near the ice shelf front. Contiguous and extensive sea ice damps ocean wave coupling sufficiently so that wintertime background levels can approach or surpass those of land-sited stations in Antarctica.
    Description: This research was supported by NSF grants PLR-1142518, 1141916, 1142126, 1246151 and 1246416. JC was additionally supported by Yates funds in the Colorado State University Department of Mathematics. PDB also received support from the California Department of Parks and Recreation, Division of Boating and Waterways under contract 11-106-107. We thank Reinhard Flick and Patrick Shore for their support during field work, Tom Bolmer in locating stations and preparing maps, and the US Antarctic Program for logistical support. The seismic instruments were provided by the Incorporated Research Institutions for Seismology (IRIS) through the PASSCAL Instrument Center at New Mexico Tech. Data collected are available through the IRIS Data Management Center under RIS and DRIS network code XH. The PSD-PDFs presented in this study were processed with the IRIS Noise Tool Kit (Bahavar and others, 2013). The facilities of the IRIS Consortium are supported by the National Science Foundation under Cooperative Agreement EAR-1261681 and the DOE National Nuclear Security Administration. The authors appreciate the support of the University of Wisconsin-Madison Automatic Weather Station Program for the data set, data display and information; funded under NSF grant number ANT-1543305. The Ross Ice Shelf profiles were generated using the Antarctic Mapping Tools (Greene and others, 2017). Regional maps were generated with the Generic Mapping Tools (Wessel and Smith, 1998). Topography and bathymetry data for all maps in this study were sourced from the National Geophysical Data Center ETOPO1 Global Relief Model (doi:10.7289/V5C8276M). We thank two anonymous reviewers for suggestions on the scope and organization of this paper.
    Keywords: Antarctic glaciology ; Ice shelves ; Seismology
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 3
    Publication Date: 2022-10-21
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ackley, S. F., Stammerjohn, S., Maksym, T., Smith, M., Cassano, J., Guest, P., Tison, J., Delille, B., Loose, B., Sedwick, P., DePace, L., Roach, L., & Parno, J. Sea-ice production and air/ice/ocean/biogeochemistry interactions in the Ross Sea during the PIPERS 2017 autumn field campaign. Annals of Glaciology, 61(82), (2020): 181-195, doi:10.1017/aog.2020.31.
    Description: The Ross Sea is known for showing the greatest sea-ice increase, as observed globally, particularly from 1979 to 2015. However, corresponding changes in sea-ice thickness and production in the Ross Sea are not known, nor how these changes have impacted water masses, carbon fluxes, biogeochemical processes and availability of micronutrients. The PIPERS project sought to address these questions during an autumn ship campaign in 2017 and two spring airborne campaigns in 2016 and 2017. PIPERS used a multidisciplinary approach of manned and autonomous platforms to study the coupled air/ice/ocean/biogeochemical interactions during autumn and related those to spring conditions. Unexpectedly, the Ross Sea experienced record low sea ice in spring 2016 and autumn 2017. The delayed ice advance in 2017 contributed to (1) increased ice production and export in coastal polynyas, (2) thinner snow and ice cover in the central pack, (3) lower sea-ice Chl-a burdens and differences in sympagic communities, (4) sustained ocean heat flux delaying ice thickening and (5) a melting, anomalously southward ice edge persisting into winter. Despite these impacts, airborne observations in spring 2017 suggest that winter ice production over the continental shelf was likely not anomalous.
    Description: NSF supported PIPERS award numbers: ANT-1341717 (S.F. Ackley, UTSA); ANT-1341513 (E. Maksym, WHOI); ANT-1341606 (S. Stammerjohn and J. Cassano, U Colorado); ANT-1341725 (P. Guest, NPS). P. Sedwick was supported by NSF ANT-1543483. S.F. Ackley was also supported by NASA Grant 80NSSC19M0194 to the Center for Advanced Measurements in Extreme Environments at UTSA. S. Stammerjohn was also supported by the LTER Program under NFS award number ANT-0823101 (H. Ducklow, LDEO/Columbia University). Additional support was by the Belgian F.R.S-FNRS (project ISOGGAP and IODIne, contract T.0268.16 and J.0262.17, respectively). Bruno Delille is a research associate of the F.R.S.-FNRS. Terra-Sar-X quicklook imagery was coordinated by Kathrin Hoeppner at DLR, and Andy Archer (with the Antarctic Support Contractor) provided selected (cloud-free) MODIS scenes and daily maps of AMSR2 sea-ice concentration.
    Keywords: Atmosphere/ice/ocean interactions ; Ice/ocean interactions ; Sea ice ; Sea-ice growth and decay
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 4
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-07-07
    Description: Freshwater ecosystems are changing their natural conditions, influenced and accelerated by human activities. These processes are capable of changing the hydrological regime and the composition of the communities, letting the future of aquatic biodiversity unknown. The construction of dams has been one of the main factors responsible for environmental changes, such as nutrients depletion, increased water transparency and loss of biodiversity in freshwater ecosystems. The aim of our study was to analyze the functional and taxonomic dissimilarity of the zooplankton community and its drivers in response to the effect of the hydrological cycle (drought and rainy), in two highly distinct floodplains, the Upper Paraná River (river with a cascade of dams) and the Amazon. A total of 72 samples were collected (16 AMA dry and 16 on rainy and 20 PAR dry and 20 on rainy) from zooplankton communities as the response variable, phytoplankton as a predictor of food, fish as a predictor of potential predators and limnological variables. Were calculated β-Total diversity and partitioned in the components β-Repl and β-Rich (taxonomic and functional approach). We expect that environmental heterogeneity is going to drive higher values of beta diversity. In sequence, distance-based redundancy analysis (db-RDA) was calculated using the distance matrices generated in the functional and taxonomic beta to assess which are the determinants of zooplankton beta diversity. Thus, we hypothesized that biotic interactions will have stronger relationships with zooplankton dissimilarity during the drought and, limnological variables and spatial component will be more important during rainy season. Greater environmental heterogeneity was found in the Amazon floodplain and also in the dry season. The beta functional and taxonomic diversity of zooplankton showed a similar relationship between the floodplains and between the hydrological periods, represented by the β-Repl component, except for the drought season in the Upper Paraná River, where the functional diversity showed the lowest values, undetected by the taxonomic approach. The factors that influenced the zooplankton beta functional and taxonomic diversity in the two floodplains were different depending on the hydrological period, reflecting once again the difference in environmental heterogeneity and the strength of hydrodynamics within each plain. The analysis of the species and functional traits distribution and, which are the variables structuring this distribution is extremely important to analyze ecosystem processes and services, especially in impacted environments such as the Upper Paraná River floodplain, and a floodplain so biodiverse as the Amazon, and even so, with the prediction of the construction of numerous dams in its hydrographic basin. We reinforce the importance of periodic flooding in these floodplains, for the maintenance of biodiversity and ecosystem services over time, and in this way, prevent biotic homogenization, and consequently, conserve these aquatic ecosystems.
    Description: Os ecossistemas de água doce estão passando por frequentes alterações nas suas condições naturais, influenciadas e aceleradas por atividades humanas. Esses processos são capazes de alterar o regime hidrológico e a composição das comunidades, deixando cada vez mais incerto o futuro da biodiversidade aquática. A construção de barramentos tem sido um dos principais responsáveis por modificações ambientais, como a redução de nutrientes, o aumento da transparência da água e a perda de biodiversidade em ecossistemas dulcícolas. O objetivo deste estudo foi analisar a dissimilaridade funcional e taxonômica da comunidade zooplanctônica e seus determinantes em resposta ao efeito do ciclo hidrológico (seca e chuva) em duas planícies de inundação altamente distintas, a planície do alto rio Paraná (rio com cascata de barramentos) e planície Amazônica. Foram coletadas 72 amostras (16 na seca e 16 na cheia na planície Amazônica e 20 na seca e 20 na cheia na palnície do alto rio Paraná) das comunidades de zooplâncton como variável resposta, de fitoplâncton como variável preditora de alimentação, de peixes como preditor de potenciais predadores e as variáveis limnológicas. Foram calculadas a diversidade β-Total e particionada nos componentes β-Repl e β-Rich em uma abordagem taxonômica e funcional, e espera-se que a heterogeneidade ambiental conduza a maiores valores de diversidade beta. Na sequência, foi calculada através das matrizes de distância geradas na beta funcional e taxonômica a análise de redundância baseada em distância (db-RDA) para avaliar quais os determinantes da diversidade beta. Assim, foi hipotetizado que as interações bióticas apresentarão relações mais fortes com a dissimilaridade zooplanctônica na seca e as variáveis limnológicas e o espaço na cheia. Foi encontrada uma maior heterogeneidade ambiental na planície Amazônica e também no período de seca. A diversidade beta funcional e taxonômica do zooplâncton apresentou uma relação semelhante entre as planícies e entre os períodoshidrológicos, representados pelo componente β-Repl, exceto pelo período de seca na planície do alto rio Paraná onde a diversidade funcional apresentou os menores valores, não detectado pela abordagem taxonômica. Os fatores que influenciaram a diversidade beta funcional e taxonômica zooplanctônica nas duas planícies de inundação foram bem distintos dependendo do período hidrológico, refletindo mais uma vez a diferença na heterogeneidade ambiental e na força da hidrodinâmica dentro de cada planície. A análise da distribuição das espécies e dos traços funcionais, e de quais variáveis estruturam essa distribuição é de extrema importância para analisar os processos e serviços ecossistêmicos, especialmente em ambientes impactados como a planície de inundação do alto rio Paraná, e uma planície tão biodiversa como a Amazônica e, mesmo assim, com previsão de construção de inúmeros barramentos em sua bacia hidrográfica. Reforça-se a importância da inundação periódica nessas planícies, para a manutenção da biodiversidade e dos serviços ecossistêmicos ao longo do tempo e, desta forma, prevenir a homogeneização biótica, e consequentemente, a conservação dos ecossistemas aquáticos.
    Description: PhD
    Keywords: Zooplâncton de água doce ; Comunidades, Ecologia de ; Diversidades beta taxonômica e funcional ; Planícies de inundação ; Floodplain ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::Y::Zooplankton ; ASFA_2015::C::Communities (ecological) ; ASFA_2015::S::Species diversity
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 56pp.
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  • 5
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-07-05
    Description: Although several studies have dealt with the description of morphological characters in Cichlidae, usually aiming for phylogenetic inference, little attention has been given to their musculature. The complete striated musculature of a cichlid species, Geophagus sveni Lucinda, Lucena & Assis, was described for the first time, with illustrations of all muscles and a protocol for the dissection of specimens. The striated musculature of at least of species of each genus in tribe Geophagini, among other cichlids, was compared, and 98 characters were described with the purpose of analysing their relation with the group’s phylogeny. This character matrix was employed to produce two unconstrained phylogenetic analyses, one weighted and the other unweighted. The myological characters were mapped upon a pre-existing phylogenetic hypothesis, for understanding the correlation among the characters and trophic specialisations of each taxon. The conclusion is that Geophagini specialised in sifting substrate (winnowers) tend to present a few convergent adaptations, manifested in the shape and degree of development of muscles such as adductor mandibulae, levator arcus palatini, dilatator operculi, adductor branchialis 1 and obliqui ventrales 1–2. This study facilitates future investigations on the functions of the striated muscles in fishes and their role in the processes of adaptive radiation, i.e., functional diversification.
    Description: Apesar de diversos estudos terem tratado da descrição de caracteres morfológicos em Cichlidae, geralmente para fins de inferência filogenética, muito pouco se estudou sobre sua musculatura. Descreveu-se, pela primeira vez, a musculatura estriada completa de uma espécie de ciclídeo, Geophagus sveni Lucinda, Lucena & Assis, com ilustrações de todos os músculos e um protocolo para a dissecção de exemplares. Comparou-se a musculatura esquelética de pelo menos uma espécie de cada gênero da tribo Geophagini, dentre outros ciclídeos, e descreveram-se 98 caracteres com o propósito de analisar sua relação com a filogenia do grupo. Essa matriz de caracteres foi empregada para produzir duas análises filogenéticas sem restrição, uma com pesagem e outra sem pesagem. Mapearam-se os caracteres miológicos sobre uma hipótese filogenética pré-existente, para a compreensão da correlação entre os caracteres e as especializações tróficas de cada táxon. Conclui-se que os Geophagini especializados em peneirar o substrato (winnowers) tendem a apresentar algumas adaptações convergentes, manifestadas na forma e no grau de desenvolvimento de músculos como adductor mandibulae, levator arcus palatini, dilatator operculi, adductor branchialis 1 e obliqui ventrales 1–2. Este estudo possibilita futuras investigações acerca das funções dos músculos estriados em peixes e seu papel nos processos de irradiação adaptativa, i.e., diversificação funcional.
    Description: PhD
    Keywords: Geophagini (Acanthopterygii, Cichlidae) “cará” ; Peixes de água doce ; Filogenia ; Morfologia ; Musculatura esquelética ; ASFA_2015::F::Freshwater fish ; ASFA_2015::T::Taxonomy ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::M::Morphology (organisms) ; ASFA_2015::P::Phylogeny ; ASFA_2015::M::Musculoskeletal system
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 234pp.
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  • 6
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-06-28
    Description: In Neotropical rivers the predation by fish and the structuring of the habitat by macrophytes influence the dynamics of the zooplankton community, altering the richness and composition of species and the richness and functional composition of the zooplankton and thus the functioning of the ecosystem. We analyzed the influence of macrophytes bank structure and predation by forage fish species on taxonomic and functional zooplankton diversity, estimated by different diversity indices (taxonomic and functional richness, taxonomic beta diversity and functional beta diversity). Thus, we assume that different levels of macrophytes structure and fish predation will alter the taxonomic and functional composition of the zooplankton (alpha and beta) between the analyzed points. Beta diversity was split into two distinct components, turnover and nesting. The zooplankton species richness was positively associated with the macrophytes richness and the macrophytes diversity. In turn, the functional richness of zooplankton had a positive association with fish richness and macrophytes richness. For the variation of total taxonomic beta diversity of zooplankton, the Generalized Dissimilarity Modeling (GDM) explained 32.58% of the total among the predictor variables. The macrophytes biomass represented the taxonomic turnover. The variation in total functional beta diversity of the zooplankton explained 9.98% by the GDM model. The abundance of fish represented the functional nesting. Macrophytes structure represented the taxonomic components and predation represented the functional components. The limnological heterogeneity of the coastal region of the Bay River made possible the colonization by multispecies macrophytes banks, influencing the alteration of the fish and zooplankton community and the more heterogeneous the environmental conditions, the greater is the capacity of colonization of different species, which can present different functional traits. The results indicate the importance of maintaining heterogeneous locations, the need to preserve the tributaries in river floodplain systems as they serve as nursery for fish spawning and contribute to a greater richness of fish, which causes an increase in the functional diversity of zooplankton.
    Description: Em rios neotropicais a predação por peixes e a estruturação do habitat por macrófitas influenciam na dinâmica da comunidade zooplanctônica, alterando a riqueza e composição de espécies e a riqueza e composição funcional do zooplâncton e, assim, o funcionamento do ecossistema. Analisou-se a influência da estruturação dos bancos de macrófitas e a predação por espécies de peixes forrageiras sobre a diversidade taxonômica e funcional zooplanctônica, estimadas por diferentes índices de diversidade (riqueza taxonômica e funcional, diversidade beta taxonômica e diversidade beta funcional). Assim, supõe-se que diferentes níveis de estruturação por macrófitas e predação por peixes alterarão a composição taxonômica e funcional do zooplâncton (alfa e beta) entre os pontos analisados. A diversidade beta foi particionada em dois componentes distintos, o turnover e o aninhamento. A riqueza de espécies do zooplâncton associou-se de forma positiva com a riqueza de macrófitas e a diversidade de macrófitas. Por sua vez, a riqueza funcional do zooplâncton teve associação positiva com a riqueza de peixes e a riqueza de macrófitas. Para a variação da diversidade beta total taxonômica do zooplâncton, a Modelagem de Dissimilaridade Generalizada (GDM) explicou 32,58% do total dentre as variáveis preditoras. A biomassa de macrófitas representou o turnover taxonômico. A variação da diversidade beta total funcional do zooplâncton, explicou 9,98% pelo modelo da GDM. A abundância de peixes representou o aninhamento funcional. A estruturação por macrófitas representou os componentes taxonômicos e a predação representou os componentes funcionais. A heterogeneidade limnológica da região litorânea do rio Baía possibilitou a colonização por bancos de macrófitas multiespecíficos, influenciando na alteração da comunidade de peixes e de zooplâncton e quanto mais heterogêneas as condições ambientais, maior é a capacidade de colonização de diferentes espécies, que podem apresentar distintos traços funcionais. Os resultados indicam a importância da manutenção de locais heterogêneos, a necessidade de preservação dos tributários em sistemas rio-planície de inundação por servirem como berçário para desova de peixes e contribuir para uma maior riqueza de peixes, o que causa um aumento na diversidade funcional do zooplâncton.
    Description: Masters
    Keywords: Zooplâncton de água doce ; Riqueza taxonômica e funcional ; Diversidade beta ; Taxonomic richness ; Functional richness ; Beta diversity ; Nestedness ; Turnover ; Comunidades, Ecologia de ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::Y::Zooplankton ; ASFA_2015::M::Macrophytes ; ASFA_2015::T::Taxonomy ; ASFA_2015::C::Communities (ecological) ; ASFA_2015::P::Predation
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 49pp.
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  • 7
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-08-31
    Description: The construction of dams is among the main anthropogenic impacts in natural freshwater systems. The first consequence of impoundments is the formation of reservoirs upstream, which represents a completely new environment compared to the natural river. In addition to this primary impact, the variations in the reservoir water level may be considered another facet of disturbances. Although several studies investigated the processes that occur in reservoirs, there is a shortfall regarding the effects of the dam operation scheme on ecosystem health. Most dams are designed to operate under two almost contrasting schemes: storage (STR) and run-of-river (ROR). These alternative operation schemes result in very different temporal variations, with STR reservoirs presenting rapid fluctuations while ROR reservoirs have a relatively constant volume. Likewise, this difference in the temporal dynamics of water level likely affects the stability of these ecosystems. In order to investigate how the dam operation scheme could affect the temporal stability of freshwater ecosystems, we used the fish communities from two reservoirs in the Iguaçu River that operate under contrasting schemes. The hypothesis was that the STR reservoir would be less stable, considering the environmental heterogeneity created by frequent water level variations, and the interactions among species would be less important for the structure of the resident fish community. In the first approach, the focus was on stability in terms of the ability to resist and recover (i.e., resistance and resilience) to disturbances. In the second approach, empirical data and simulations were used to assess which mechanism (species interactions, environmental or demographic stochasticity) underlie the synchrony of fish communities. Contrary to the expectation, the results showed the ROR reservoir as less stable than the STR, and the mechanisms underlying species synchrony coincided between reservoirs but played opposite roles. More specifically, the temporal dynamics imposed by ROR operation may have weakened the species-environment relationships, which led to a less stable community. Although the results were consistent, they were only primary evidence and such cause-effect relationships between dam operation and its effects on ecosystem stability require further investigations.
    Description: A construção de barragens está entre os principais impactos antropogênicos em ambientes de água doce. A primeira consequência dos barramentos é a formação de um reservatório à montante, que representa um ambiente completamente modificado, em relação ao rio natural. Impactos secundários, como as variações no nível da água, também podem ser considerados outros tipos de distúrbio. Embora vários estudos investigaram os processos que ocorrem em reservatórios, existe uma lacuna a respeito dos efeitos do modo de operação da barragem sobre a estado dos ecossistemas. A maioria das barragens é projetada para operar sob dois modos: acumulação (ACU) e fio d’água (FDA). Esses modos alternativos resultam em variações temporais muito distintas, com reservatórios ACU apresentando flutuações rápidas, enquanto reservatórios FDA possuem volume relativamente constante. Do mesmo modo, essa diferença na dinâmica temporal do nível da água provavelmente afeta a estabilidade desses ecossistemas. A fim de investigar como o modo de operação da barragem pode afetar a estabilidade temporal dos ambientes de água doce, foram utilizadas comunidades de peixes de dois reservatórios do rio Iguaçu, que operam sob modos diferentes. A hipótese testada foi que o reservatório ACU seria menos estável, considerando a heterogeneidade ambiental criada pelas variações frequentes no nível da água, e as interações entre as espécies seriam menos importantes para a estrutura da comunidade de peixes. Na primeira abordagem, o foco foi na estabilidade em termos da habilidade em resistir e se recuperar (i.e., resistência e resiliência) aos distúrbios. Na segunda abordagem, dados empíricos e simulações foram utilizados para verificar quais mecanismos (interações entre espécies, ou estocasticidade ambiental/demográfica) seriam subjacentes à sincronia das comunidades de peixes. Ao contrário do esperado, os resultados mostraram que o reservatório FDA foi menos estável do que o reservatório ACU e os mecanismos subjacentes à sincronia das espécies coincidiram entre os reservatórios, mas com papéis opostos. Mais especificamente, a dinâmica temporal imposta pela operação do reservatório FDA provavelmente enfraqueceu as relações espécie-ambiente, o que levou a uma comunidade menos estável. Embora os resultados sejam consistentes, são apenas indícios primários e as relações de causa-e-efeito entre o modo de operação da barragem e a estabilidade dos ecossistemas requer investigações futuras.
    Description: PhD
    Keywords: Peixes de água doce ; Reservatórios de água doce ; Environmental stochasticity ; Reservatórios ; Comunidades, Ecologia de ; Competição interespecífica ; Impactos ambientais antropogênicos ; Manejo ; ASFA_2015::F::Freshwater fish ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::N::Niches ; ASFA_2015::C::Communities (ecological) ; ASFA_2015::I::Impacts ; ASFA_2015::C::Competition ; ASFA_2015::R::Reservoirs (water) ; ASFA_2015::S::Species diversity ; ASFA_2015::I::Interactions ; ASFA_2015::I::Impoundments
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 98pp.
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  • 8
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-09-01
    Description: Plagioscion squamosissimus (Heckel, 1840) (Sciaenidae), known as “corvina” is a native species of Amazon basin and it is a model for studding their parasites. Intending to analyze ectoparasites ecological aspects, such as distribution and interactions, gills of twenty specimens were analyzed, from rio Tapajós, in the region of Santarém-PA, Brazil. Ecological analyzes considered distribution of parasites between host specimens and also microhabitats occupied by ectoparasites. Eighteen ectoparasites species were founded, fourteen monogenetic and four copepods. Considering species abundance, monogenetic were the dominant group and Euryhaliotrema thatcheri was the most abundant in all analyzed hosts. There was a significate correlation between some parasite species abundance and prevalence with total length and host condition factor. Each species of parasite presented an aggregate distribution pattern. The community of P. squamosissimus ectoparasites were interactive. Considering the distribution of the species in the gills, there was a significant difference in the composition between arches, segments and regions. It is suggested that this distribution is related to factors related to microhabitat, such as water flow and area available for fixation of parasites, as well as the structures of fixation of each species and interactions such as positive associations and competition. During the investigation of the material, specimens that differed from the species already described were founded, so three new monogenetic species were proposed, belonging to the genus Aetheolabes, Anakohnia and Euryhaliotrema, based on their morphological characteristics.
    Description: A corvina de água doce ou pescada branca, Plagioscion squamosissimus (Heckel, 1840) (Sciaenidae) se distribui pela bacia Amazônica e que como hospedeira, consiste em um modelo para o estudo de seus parasitas. Analisou-se os aspectos ecológicos da fauna ectoparasitária de P. squamosissimus, tais como a distribuição e as interações e entre as espécies, por meio das brânquias de vinte espécimes coletados no rio Tapajós, região de Santarém-PA. Considerou-se a distribuição de parasitas entre os espécimes de hospedeiros e também, a partir dos microhabitats que os ectoparasitas ocupavam nesses espécimes. Foram encontradas dezoito espécies de ectoparasitas, dentre os quais catorze monogenéticos e quatro copépodes. Em relação a abundância das espécies, os monogenéticos destacaram-se como grupo dominante e, dentre estas espécies, Euryhaliotrema thatcheri apresentou-se como a mais abundante em todos os hospedeiros analisados. Houve correlação da abundância e da prevalência de algumas espécies de parasitas com o comprimento total e o fator de condição dos hospedeiros. Cada espécie de parasita apresentou padrão de distribuição agregado. A comunidade de ectoparasitas de P. squamosissimus foi considerada interativa. Em relação à distribuição das espécies nas brânquias, houve diferença significativa na composição entre os arcos, segmentos e regiões. Sugere-se que esta distribuição se relaciona com fatores referentes ao microhabitat, como o fluxo de água e a área disponível para fixação dos parasitas, bem como as estruturas de fixação de cada espécie e também interações como associações positivas e competição. Durante a investigação do material, os espécimes encontrados diferiram das espécies previamente descritas, de modo que realizou-se a proposta de três novas espécies de monogenéticos pertencentes aos gêneros Aetheolabes, Anakohnia e Euryhaliotrema a partir de suas características morfológicas.
    Description: PhD
    Keywords: Fauna ectoparasitária ; Monogenea ; Copepoda ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::F::Freshwater fish ; ASFA_2015::P::Parasites ; ASFA_2015::E::Ectoparasites ; ASFA_2015::E::Ectoparasitism
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 83pp.
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  • 9
    Publication Date: 2022-10-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hughen, K. A., & Heaton, T. J. Updated Cariaco Basin C-14 calibration dataset from 0-60 cal kyr BP. Radiocarbon, 62(4), (2020): 1001-1043, doi:10.1017/RDC.2020.53.
    Description: We present new updates to the calendar and radiocarbon (14C) chronologies for the Cariaco Basin, Venezuela. Calendar ages were generated by tuning abrupt climate shifts in Cariaco Basin sediments to those in speleothems from Hulu Cave. After the original Cariaco-Hulu calendar age model was published, Hulu Cave δ18O records have been augmented with increased temporal resolution and a greater number of U/Th dates. These updated Hulu Cave records provide increased accuracy as well as precision in the final Cariaco calendar age model. The depth scale for the Ocean Drilling Program Site 1002D sediment core, the primary source of samples for 14C dating, has been corrected to account for missing sediment from a core break, eliminating age-depth anomalies that afflicted the earlier calendar age models. Individual 14C dates for the Cariaco Basin remain unchanged from previous papers, although detailed comparisons of the Cariaco calibration dataset to those from Hulu Cave and Lake Suigetsu suggest that the Cariaco marine reservoir age may have shifted systematically during the past. We describe these recent changes to the Cariaco datasets and provide the data in a comprehensive format that will facilitate use by the community.
    Description: K.A. Hughen was supported by funds from U.S. NSF grant #OCE-1657191, and by the Investment in Science Fund at WHOI. T.J. Heaton is supported by a Leverhulme Trust Fellowship RF-2019-140\9, “Improving the Measurement of Time Using Radiocarbon”.
    Keywords: Calibration ; Climate ; Radiocarbon
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 10
    Publication Date: 2022-10-20
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ackley, S. F., Perovich, D. K., Maksym, T., Weissling, B., & Xie, H. Surface flooding of Antarctic summer sea ice. Annals of Glaciology, 61(82), (2020): 117-126, doi:10.1017/aog.2020.22.
    Description: The surface flooding of Antarctic sea ice in summer covers 50% or more of the sea-ice area in the major summer ice packs, the western Weddell and the Bellingshausen-Amundsen Seas. Two CRREL ice mass-balance buoys were deployed on the Amundsen Sea pack in late December 2010 from the icebreaker Oden, bridging the summer period (January–February 2011). Temperature records from thermistors embedded vertically in the snow and ice showed progressive increases in the depth of the flooded layer (up to 0.3–0.35 m) on the ice cover during January and February. While the snow depth was relatively unchanged from accumulation (〈10 cm), ice thickness decreased by up to a meter from bottom melting during this period. Contemporaneous with the high bottom melting, under-ice water temperatures up to 1°C above the freezing point were found. The high temperature arises from solar heating of the upper mixed layer which can occur when ice concentration in the local area falls and lower albedo ocean water is exposed to radiative heating. The higher proportion of snow ice found in the Amundsen Sea pack ice therefore results from both winter snowfall and summer ice bottom melt found here that can lead to extensive surface flooding.
    Description: This work was supported by the National Science Foundation grant to UTSA, ANT-0839053-Sea Ice System in Antarctic Summer (S.F. Ackley, H. Xie and B. Weissling), and to WHOI, ANT-1341513 (T. Maksym), and by the NASA Center for Advanced Measurements in Extreme Environments or NASA-CAMEE at UTSA, NASA #80NSSC19M0194 (S.F. Ackley, H. Xie, B.Weissling).
    Keywords: Ice/ocean interactions ; Sea ice ; Sea-ice growth and decay ; Snow/ice surface processes
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 11
    Publication Date: 2022-10-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Reimer, P. J., Austin, W. E. N., Bard, E., Bayliss, A., Blackwell, P. G., Ramsey, C. B., Butzin, M., Cheng, H., Edwards, R. L., Friedrich, M., Grootes, P. M., Guilderson, T. P., Hajdas, I., Heaton, T. J., Hogg, A. G., Hughen, K. A., Kromer, B., Manning, S. W., Muscheler, R., Palmer, J. G., Pearson, C., van der Plicht, J., Reimer, R. W., Richards, D. A., Scott, E. M., Southon, J. R., Turney, C. S. M., Wacker, L., Adolphi, F., Buentgen, U., Capano, M., Fahrni, S. M., Fogtmann-Schulz, A., Friedrich, R., Koehler, P., Kudsk, S., Miyake, F., Olsen, J., Reinig, F., Sakamoto, M., Sookdeo, A., & Talamo, S. The Intcal20 Northern Hemisphere radiocarbon age calibration curve (0-55 cal kBP). Radiocarbon, 62(4), (2020): 725-757, doi:10.1017/RDC.2020.41.
    Description: Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
    Description: We would like to thank the National Natural Science Foundation of China grants NSFC 41888101 and NSFC 41731174, the 111 program of China (D19002), U.S. NSF Grant 1702816, and the Malcolm H. Wiener Foundation for support for research that contributed to the IntCal20 curve. The work on the Swiss and German YD trees was funded by the German Science foundation and the Swiss National Foundation (grant number: 200021L_157187). The operation in Aix-en-Provence is funded by the EQUIPEX ASTER-CEREGE, the Collège de France and the ANR project CARBOTRYDH (to EB). The work on the correlation of tree ring 14C with ice core 10Be was partially supported by the Swedish Research Council and the Knut and Alice Wallenberg foundation. M. Butzin was supported by the German Federal Ministry of Education and Research (BMBF) as Research for Sustainable Development (FONA; http://www.fona.de) through the PalMod project (grant number: 01LP1505B). S. Talamo and M. Friedrich are funded by the European Research Council under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement No. 803147-RESOLUTION, awarded to ST). CA. Turney would like to acknowledge support of the Australian Research Council (FL100100195 and DP170104665). P. Reimer and W. Austin acknowledge the support of the UKRI Natural Environment Research Council (Grant NE/M004619/1). T.J. Heaton is supported by a Leverhulme Trust Fellowship RF-2019-140\9. Other datasets and the IntCal20 database were created without external support through internal funding by the respective laboratories. We also would like to thank various institutions that provided funding or facilities for meetings.
    Keywords: Calibration curve ; Radiocarbon ; IntCal20
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 12
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-07-01
    Description: Generalist species can be composed of specialist individuals, who use a small part of the population's niche. This process is known as individual specialization and can involve changes in diet and morphology. In this study, we hypothesized that individual variations in the diet and morphology of fish associated with macrophytes are related to the habitat’s complexity and greater levels of individual specialization will be found in the intermediate levels of macrophyte biomass. Fish and macrophytes were sampled in 30 multispecific macrophytes stands with different biomasses in a 13.7 km stretch of the rio Baía (Paraná River floodplain). Habitat complexity was assessed using the biomass of aquatic macrophytes (five stands with low biomass, five with intermediate biomass and five with high biomass were selected) and the fish species used in this study was Moenkhausia forestii. The individuals' diet was evaluated using the volumetric method, and the morphology through 18 linear measurements and six area measurements. To assess individual specialization in the diet, the Specialization Index (IS) and the NODF nesting index were used. Individual morphological specialization was assessed using ecomorphological diversity for each level of macrophyte biomass. Correlations between diet and morphology were assessed using the Mantel test. IS and NODF values indicated greater individual specialization in the diet in macrophytes stands with low biomass. The greatest individual morphological specialization was found in macrophytes stands with intermediate biomasses. The Mantel test showed that there was no significant correlation between diet and morphology. The individual specialization of M. forestii diet is related to the increase in competition, mainly intraspecific, intensified by the low availability of resources in low biomass stands. Morphological specialization, in turn, is related to greater availability and accessibility to resources within the intermediate biomass stands, where there are ideal conditions for increasing richness and abundance of resources and little structural complexity when compared to high biomass stands.
    Description: Espécies generalistas podem ser compostas por indivíduos especialistas, que utilizam uma pequena parte do nicho da população. Este processo é conhecido como especialização individual e pode envolver mudanças na dieta e na morfologia. Investigou-se a hipótese de que variações individuais na dieta e na morfologia de peixes associados à macrófitas estão relacionadas à complexidade do habitat e que maiores níveis de especialização individual serão encontrados nos níveis intermediários de biomassa de macrófitas. Foram amostrados peixes e macrófitas em 30 bancos multiespecíficos de macrófitas com diferentes biomassas em um trecho de 13,7 km de extensão do rio Baía (planície de inundação do rio Paraná). A complexidade do habitat foi medida por meio da biomassa das macrófitas aquáticas (selecionou-se cinco bancos com biomassas baixas, cinco com biomassas intermediárias e cinco com biomassas altas) e a espécie de peixe utilizada foi Moenkhausia forestii. Analisou-se a dieta dos indivíduos mediante o método volumétrico e a morfologia mediante 18 medidas lineares e seis medidas de área. Para avaliar a especialização individual na dieta utilizou-se o Índice de Especialização (IS) e o Índice NODF de aninhamento. A especialização individual morfológica foi avaliada por intermédio da diversidade ecomorfológica para cada nível de biomassa de macrófitas. As correlações entre a dieta e a morfologia foram avaliadas por meio de um teste de Mantel. Os valores de IS e NODF indicaram maior especialização individual na dieta em bancos de macrófitas com baixas biomassas. A maior especialização morfológica individual foi verificada em bancos de macrófitas com biomassas intermediárias. O teste de Mantel mostrou que não houve correlação significativa entre a dieta e a morfologia. A especialização individual da dieta de M. forestii está relacionada com o aumento da competição, principalmente intraespecífica, intensificada pela baixa disponibilidade de recursos nos bancos de baixas biomassas. A especialização morfológica por sua vez está relacionada com a maior disponibilidade e acessibilidade aos recursos dentro dos bancos de biomassas intermediárias, onde existem condições ideais para o aumento da riqueza e abundância de recursos e pouca complexidade estrutural quando comparado aos bancos de biomassa alta.
    Description: Masters
    Keywords: Populações, Ecologia de ; Ecologia trófica ; Macrófitas aquáticas ; Especialização individual ; Indivíduos da mesma espécie ; Complexidade estrutural ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::A::Aquatic plants ; ASFA_2015::M::Macrophytes ; ASFA_2015::P::Population dynamics ; ASFA_2015::C::Communities (ecological) ; ASFA_2015::P::Population structure ; ASFA_2015::T::Trophic levels
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 38pp.
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  • 13
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-09-05
    Description: The differential distribution of productivity in reservoirs has consequences for the fish assemblage, influencing spatially in its distribution, along a longitudinal gradient. Following the hypothesis that the spatiotemporal dynamics of chlorophyll a and turbidity influence the distribution of the fish assemblage in the Sobradinho reservoir, BA, three predictions were tested: i) Whether the spatiotemporal variations of these variables, determined by digital processing of remote sensing images, follow the spatial zoning pattern described in the literature, for large reservoirs; ii) Whether with the increase in distance, in kilometers, from the collection points to the dam, there is an increase in the total abundance of fish; and iii) If, with the increase in productivity, represented by higher concentrations of chlorophyll a and turbidity, there is an increase in the abundance of fish (total or by trophic guild). The sampling was distributed in five periods, between April 2008 and July 2009, with at least one collection being carried out in each zone of the reservoir, fluvial, transition and lake, in each period. Bands 2 and 3 of scenes from the Landsat-5 satellite were selected, in which the chosen limnological variables show their peak of reflection. With the values of the collections in situ and the reflectance of the scenes, an interpolation was performed and, later, thematic maps of each of the variables were elaborated. The chlorophyll a and turbidity values of the ichthyofauna collection points were extracted from the interpolations. To analyze the existence of the longitudinal gradient, Spearman correlation analyses were performed between the value of the limnological variables and the distance from the collection point to the dam, obtained by extracting a longitudinal profile of the reservoir. To search for associations between limnological variables and ichthyofauna, Spearman's correlation analyses were performed with the value of the variables and total abundance and by trophic guilds. Also, the analyses were carried out dividing the collection points according to the reservoir area and the rainfall regime (dry and full). The Sobradinho reservoir showed a pattern of productivity zoning consistent with the typical pattern of large reservoirs. This zoning had a strong association with the distribution of fish abundance in the Sobradinho reservoir. There was an association between the abundance of fish in the lake area and the seasonal increase in productivity, with a remarkable decrease in abundance during the dry months and an increase in abundance during the floods. However, in the river zone, excess turbidity acted as a limiting factor. High values of this variable, also showing a greater flow of water, may have favored the dispersion of organisms to places of lesser environmental stress, reducing the abundance of fish in this region during floods. However, in general, the fluvial zone showed the highest abundances, exhibiting the well-known fluvial〉 transition〉 lacustrine pattern. The presence of favorable characteristics in the river zone, such as seasonal flooding and greater environmental heterogeneity, may have contributed to this result.
    Description: A distribuição diferencial da produtividade em reservatórios apresenta consequências sobre a assembleia de peixes, influenciando espacialmente na sua distribuição, ao longo de um gradiente longitudinal. Seguindo a hipótese de que as dinâmicas espaço-temporais de clorofila a e turbidez têm influência na distribuição da assembleia de peixes no reservatório de Sobradinho, BA, foram testadas três predições: i) Se as variações espaço-temporais destas variáveis, determinadas por processamento digital de imagens de sensoriamento remoto, seguem o padrão espacial de zonação descrito na literatura, para grandes reservatórios; ii) Se com o aumento da distância, em quilômetros, dos pontos de coleta em relação à barragem há incremento na abundância total de peixes; e iii) Se com o aumento da produtividade, representada por maiores concentrações de clorofila a e turbidez, há incremento na abundância de peixes (total ou por guilda trófica). A amostragem foi distribuída em cinco períodos, entre abril de 2008 e julho de 2009, sendo realizada pelo menos uma coleta em cada zona do reservatório, fluvial, transição e lacustre, em cada período. Selecionou-se as bandas 2 e 3 de cenas do satélite Landsat-5, nas quais as variáveis limnológicas escolhidas apresentam seu pico de reflexão. Com os valores das coletas in situ e a reflectância das cenas foi realizada uma interpolação e, posteriormente elaborou-se mapas temáticos de cada uma das variáveis. Os valores de clorofila a e turbidez dos pontos de coleta da ictiofauna foram extraídos das interpolações. Para analisar a existência do gradiente longitudinal, realizou-se análises de correlação de Spearman entre o valor das variáveis limnológicas e a distância do ponto de coleta em relação à barragem, obtidos através da extração de um perfil longitudinal do reservatório. Para buscar associações entre as variáveis limnológicas e a ictiofauna realizou-se análises de correlação de Spearman com o valor das variáveis e abundância total e por guilda trófica. Também, efetuou-se as análises dividindo os pontos de coleta de acordo com a zona do reservatório e com o regime pluviométrico (seca e cheia). O reservatório de Sobradinho apresentou um padrão de zonação de produtividade condizente com o padrão típico de grandes reservatórios. Esta zonação teve forte associação com a distribuição da abundância de peixes no reservatório de Sobradinho. Foi evidenciada uma associação entre a abundância de peixes da zona lacustre e o incremento sazonal da produtividade, sendo notável a diminuição da abundância durante os meses secos e o incremento desta durante as cheias. No entanto, na zona fluvial, o excesso de turbidez agiu como um fator limitante. Valores altos dessa variável, evidenciando também maior fluxo d’água, podem ter favorecido a dispersão dos organismos para locais de menor stress ambiental, diminuindo a abundância de peixes nesta região durante as cheias. Entretanto, em geral, a zona fluvial apresentou as maiores abundâncias, exibindo o conhecido padrão fluvial 〉 transição 〉 lacustre. A presença de características favoráveis na zona fluvial, como inundação sazonal e maior heterogeneidade ambiental, podem ter contribuido para esse resultado.
    Description: Masters
    Keywords: Ictiofauna de água doce ; Sensoriamento remoto orbital (SR) ; Reservatórios ; Variáveis limnológicas ; Gradiente longitudinal ; ASFA_2015::I::Ichthyofauna ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::R::Reservoirs (water) ; ASFA_2015::V::Variability ; ASFA_2015::L::Limnology ; ASFA_2015::R::Remote sensing
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 45pp.
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  • 14
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-09-05
    Description: The use of multimetric indices (MMIs) to assess ecological conditions in aquatic environments has been applied globally. These indices are practical tools that incorporate various biotic metrics at different levels of biological organization. However, criticism has been directed to the use of MMIs, especially regarding the methodological criteria applied in the process such as related to metric selection and scoring and identification of reference conditions that consider all sources of ecological integrity disturbance. A review of the scientific literature was carried out to evaluate processes of creation and validation of MMIs worldwide. The criteria used by scientists to identify reference conditions, metric selection and scoring, the main metrics globally used in MMIs, and the challenges in applying these indices were verified. It was identified whether nonnative species have been considered as a source of degradation of ecological integrity in the MMIs application. The results indicated that there are no common criteria for determining reference conditions, for metric selection and scoring, which makes it difficult to compare different programs and regions, and to develop or improve future MMIs. The results showed that metrics related to species richness were most frequently used in MMIs applied worldwide, thus, it represents a consistent response pattern in the assessment of ecological conditions. The results also indicate that differentiating natural variability from anthropogenic impacts was evidenced as the major challenge in the MMIs creation and application. The review of the scientific literature indicated that biological invasions are neglected in ecological integrity assessments, as nonnative species are rarely considered as a disturbing factor in identifying reference conditions and species origin metrics are not widely used in MMIs. The results presented in this review may promote the advancement and improvement of MMIs as bioassessment tools.
    Description: O uso de índices multimétricos (MMIs) para avaliação das condições ecológicas em ambientes aquáticos tem sido aplicado globalmente. Estes índices são ferramentas práticas que incorporam várias métricas bióticas em diferentes níveis de organização biológica. No entanto, críticas têm sido endereçadas ao uso de MMIs, especialmente em relação aos critérios metodológicos empregados no processo, como a seleção e pontuação de métricas e identificação de condições de referência que considerem todas as fontes de perturbação da integridade ecológica. Efetuou-se uma revisão de literatura científica a fim de avaliar processos de criação e validação de MMIs em todo o mundo. Verificou-se os critérios usados pelos cientistas para identificação de condições de referência, seleção e pontuação de métricas, as principais métricas usadas globalmente nos MMIs e os desafios na aplicação desses índices. Foi verificado se espécies não nativas têm sido consideradas como fonte de degradação da integridade ecológica na aplicação de MMIs. Os resultados obtidos indicaram que não existem critérios comuns para determinação das condições de referência e seleção e pontuação de métricas, o que dificulta a avaliação comparável entre diferentes programas e regiões e desenvolvimento ou aprimoramento de futuros MMIs. Os resultados mostraram que as métricas de riqueza de espécies foram as mais frequentemente usadas nos MMIs aplicados em todo o mundo, representando, assim, um padrão de resposta consistente na avaliação das condições ecológicas. Os resultados obtidos também sugerem que diferenciar a variabilidade natural dos impactos antropogênicos foi evidenciado como o maior desafio na criação e aplicação de MMIs. A revisão da literatura científica indicou que invasões biológicas são negligenciadas em avaliações de integridade ecológica, pois espécies não nativas são raramente consideradas como fator de perturbação na identificação de condições de referência e métricas de origem das espécies não são amplamente empregadas nos MMIs. Os resultados apresentados nessa revisão podem promover o avanço e aprimoramento dos MMIs como ferramentas de bioavaliação.
    Description: PhD
    Keywords: Ecossistemas de água doce ; Biomonitoramento ; Invasões biológicas ; Indicadores biológicos ; Índice de Integridade Biótica ; Seleção de métricas ; Integridade ecológica ; Indicadores ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::E::Ecosystems ; ASFA_2015::B::Bioindicators ; ASFA_2015::I::Indigenous species
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 92pp.
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  • 15
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-09-02
    Description: Changes in the biodiversity of parasites communities can be used as indicators of the healthy ecosystem as they reflect environmental impacts through their responses to changes in habitat. Thus, the aim of the study was to investigate the potential use of parasites from Geophagus brasiliensis as bioindicators of environmental changes. Three sample points were determined of rio Iguaçu with different degrees of environmental impact. Among 69 specimes analyzed of G. brasiliensis, 32 (46.3%) were parasitized by at least one parasite. A total of 56 specimens of endoparasites belonging to the phylum Nematoda were collected. The abundance of nematode species was significantly higher in fishes collected in point 3 (Kruskal-Wallis2;69 = 8.62; p = 0.01) and species composition between points were significantly different (F = 6.95, p = 0.002). There was no significant difference in relative condition factor (Kn) of G. brasilienses between the points (F2;66 = 2.54; p = 0.08) there was no correlation in Kn and abundance of nematodes (rs = 0.1; p = 0.4). The lower abundance of nematodes was observed in point 1 (critically degraded), due to this environment showing changes in abiotic factors, represented in the relatively high values of conductivity and phosphorus when compared with points 2 and 3 (moderately degraded).The results obtained in the present study indicate that the parasitic community of G. brasiliensis is characterized by low diversity in polluted locations, thus the absence of certain species of parasites and the occurrence of nematode species demonstrated a variation in response to the pollution gradient.
    Description: Alterações na biodiversidade de comunidades parasitárias são utilizadas como indicadoras da saúde de sistemas ecológicos, pois refletem impactos ambientais mediante suas respostas às alterações no habitat. Investigou-se o potencial uso de nematoides de Geophagus brasiliensis como indicadores de alterações ambientais mediante o registro de sua presença e ausência. Foram determinados três pontos amostrais no rio Iguaçu com diferentes graus de impacto ambiental. Entre os 69 espécimes de G. brasiliensis analisados, 32 (46,3%) estavam parasitados por pelo menos um parasita. Um total de 56 espécimes de endoparasitas pertencentes a Nematoda foram coletados. A abundância de espécies de nematoides foi significativamente maior em peixes coletados no ponto 3 (Kruskal-Wallis 2;69 = 8,62; p = 0,01) e a composição das espécies entre os pontos foram significativamente diferentes (F = 6,95, p = 0,002). Não houve diferença significativa no fator de condição relativo (Kn) de G. brasiliensis entre os pontos (F2;66 = 2,54; p = 0,08) e na correlação entre o Kn e a abundância de nematoides (rs = 0,1; p = 0,4). A menor abundância foi verificada no ponto 1 (criticamente degradado), devido a esse ambiente apresentar alterações nos fatores abióticos e na estrutura biológica, quando comparado com os pontos 2 e 3 (moderadamente degradados). Os resultados obtidos indicam que a comunidade parasitária de G. brasiliensis é caracterizada por baixa diversidade em locais poluídos, portanto a ausência de certas espécies de parasitas e a ocorrência de espécies de nematoides demonstraram uma variação em resposta ao gradiente de poluição.
    Description: Masters
    Keywords: Peixes de água doce ; Ictioparasitologia de água doce ; Ecotoxicologia aquática ; Rio impactado ; Parasitas ; Ecotoxicologia ; Bioindicadores ; ASFA_2015::F::Freshwater fish ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::P::Parasites ; ASFA_2015::E::Ecotoxicology ; ASFA_2015::B::Bioindicators ; ASFA_2015::I::Impacts
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 26pp.
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  • 16
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-09-02
    Description: Several studies have presented phylogeny of Geophagini based on morphological and molecular characters; however, neuroanatomical characters have not been explored for the tribe yet. Fish encephalon shows interspecific morphological variation, even in related groups, and can be used to build cladograms. The phylogeny of Geophagini is presented using the neuroanatomical characters mapped on a previous cladogram. This approach showed how the encephalon of Geophagini species have diversified among clades and how ecological features of some species can be related to changes (increase or decrease) of a particular structure. The morphological description of the encephalon of Geophagus sveni was also performed, with an illustration of the major encephalon structures and the origin of the cranial nerves, as well as a comparison of the morphometric differences between males and females.
    Description: Diversos estudos apresentaram a filogenia de Geophagini com base em caracteres morfológicos e moleculares, entretanto, caracteres neuroanatômicos ainda não foram explorados para a tribo. Os cérebros de peixes apresentam variação morfológica interespecífica, mesmo em grupos aparentados, podendo ser utilizados para construção de cladogramas. A filogenia de Geophagini é apresentada com a utilização dos caracteres neuroanatômicos mapeados sobre um cladograma prévio. Esta abordagem evidenciou como o encéfalo de Geophagini se diversificou entre os clados e como características ecológicas de cada espécie podem estar relacionados com modificações (aumento ou diminuição) de uma estrutura em particular. Foi realizada também a descrição morfológica do encéfalo de Geophagus sveni, com ilustração das principais estruturas do encéfalo e origem dos nervos cranianos, assim como a comparação das diferenças morfométricas entre machos e fêmeas.
    Description: Masters
    Keywords: Geophagini (Cichliformes: Cichlidae: Cichlinae) ; Filogenia ; Encéfalo ; Morfologia ; ASFA_2015::F::Freshwater fish ; ASFA_2015::P::Phylogeny ; ASFA_2015::M::Morphology (organisms) ; ASFA_2015::B::Brain ; ASFA_2015::A::Anatomical structures ; ASFA_2015::T::Taxonomy
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 137pp.
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  • 17
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-09-02
    Description: Biodiversity encompasses multiple aspects or facets changing in space and time. Before a loss of biodiversity in response to anthropogenic impacts it is of the utmost importance to determine what facets of biodiversity are altered and the determinants of such changes. By using information from species abundance, their evolutionary relatedness, and ecological traits we determine how the dissimilarity in composition of fish communities is influenced by temporal changes in land use and changes in environmental heterogeneity across space. In the first approach, we can see that changes in land use over time affected mainly the substitution of evolutionary lineages and functional traits. In the second approach, we find evidence of taxonomic and functional homogenization over time, likely following a decrease in diversity of traits related to habitat use. Furthermore, we found that ecological traits contributed differently to the changes in functional composition as well in their response to environmental heterogeneity. These results support recently evidence showing that anthropogenic impacts are driving changes in biological communities through a taxonomic and functional homogenization.
    Description: A biodiversidade está constituída por múltiplos aspectos ou facetas que mudam no espaço e tempo. Ante um cenário de perda de diversidade em resposta a impactos antropogênicos é urgente determinar quais aspectos da biodiversidade estão sendo alterados e os determinantes de tais mudanças. Usando informação de abundância de espécies, suas relações evolutivas e características ecológicas, determinamos como dissimilaridade da composição entre comunidades de peixes é influenciada por mudanças no uso da terra ao longo do tempo e mudanças da heterogeneidade ambiental no espaço. Na primeira abordagem, podemos ver que ao longo do tempo as mudanças no uso da terra afetam principalmente a substituição de linhagens evolutivas e características ecológicas. Na segunda abordagem, encontramos evidência de que as comunidades estão sendo homogeneizadas taxonômica e funcionalmente ao longo do tempo, provavelmente devido à perda de diversidade em características relacionadas ao uso de habitat. Ademais, encontramos que as características ecológicas contribuem de forma diferente para as mudanças na composição funcional e apresentam diferenças na resposta à heterogeneidade ambiental. Esses resultados suportam evidências de que impactos antropogênicos estão levando a mudanças nas comunidades biológicas, as quais estão tendendo a perder diversidade mediante homogeneização taxonômica e funcional
    Description: PhD
    Keywords: Peixes de água doce ; Comunidades, Ecologia de ; Impactos ambientais antropogênicos ; Mudanças espaciais e temporais ; Diversidades funcional e filogenética ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::F::Freshwater fish ; ASFA_2015::C::Communities (ecological) ; ASFA_2015::L::Land use ; ASFA_2015::P::Phylogenetics ; ASFA_2015::F::Functional analysis ; ASFA_2015::E::Ecological diversity ; ASFA_2015::T::Temporal variations ; ASFA_2015::T::Taxonomy ; ASFA_2015::E::Environmental impact
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 89pp.
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  • 18
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-09-02
    Description: Different ecological processes (e.g., rescue effect, environmental filtering, limiting similarity and dispersal) shape the structure of ecological communities. These processes, which are related to the theories of metapopulation and metacommunities, guided this study. For this purpose, data from fish communities in streams in the Upper Araguaia river basin (Mato Grosso and the Goiás States, Brazil) were used. It was observed that the regional distribution of fish species was modelled according to niche attributes (position and breadth), body size, trophic position, and swimming capacity. The results indicated that average abundance, niche position and niche amplitude predict the regional distribution of the species. Taken together, these results suggest the importance of metapopulation dynamics and niche-based processes explaining the regional distribution of species in the studied system. At another time, it was tested whether the abundance of subordinate species (i.e., any species that are not dominant in a local community) was correlated with the functional distance between dominant and subordinate species. In the results, a negative relationship between these quantities and that the subordinate species had larger body sizes compared to the dominant species in the local communities. These results also suggest that species filtering is more important than the interspecific competition to explain the patterns of species abundance distribution. In this study, was analyzed the relative importance of local environmental, landscape and spatial variables in structuring fish communities in streams of “veredas” (small wetlands in the Cerrado). The local environmental variables, after controlling the effect of space, were clearly more important than those obtained at the landscape scale. In view of the observations, it is concluded that the use of landscape data, in studies seeking environmental correlates of local community structure, should not occur at the expense of obtaining local variables (mainly those related to the habitat structure). The results of the three investigations in this study shown the predominant role of local environmental filters in the structuring of the fish communities analyzed. Species with high niche amplitude tend to have wide regional distributions and small-bodied ones tend to be locally dominant.
    Description: Diversos processos ecológicos, tais como efeito resgate, filtragem ambiental, similaridade limitante e dispersão atuam na estruturação das comunidades. Esses processos, relacionados às teorias de metapopulação e metacomunidades, direcionaram este estudo. Para tanto, dados de comunidades de peixes em riachos do Alto da bacia do rio Araguaia (estados do Mato Grosso e Goiás, Brasil) foram utilizados. Foi observado que a distribuição regional das espécies de peixes em função de atributos do nicho (posição e amplitude), tamanho do corpo, posição trófica e capacidade natatória. Observou-se que apenas a abundância média, a posição de nicho e a amplitude de nicho predizem a distribuição regional das espécies. Em conjunto, esses resultados indicam a importância da dinâmica metapopulacional e de processos baseados no nicho para explicar a distribuição regional das espécies de peixes de riachos do Cerrado. Em outro momento, foi testado se a abundância de espécies subordinadas (i.e., quaisquer espécies que não são dominantes numa comunidade local) estava correlacionada com a distância funcional entre espécies dominantes e subordinadas. Nos resultados, encontrou-se uma relação negativa entre essas quantidades e que as espécies subordinadas apresentavam maiores tamanhos corpóreos em comparação com as espécies dominantes nas comunidades locais. Esses resultados mostram que a filtragem de espécies é mais importante que a competição interespecífica para explicar a distribuição da abundância entre as espécies. Neste estudo, foi analisada a importância relativa de variáveis ambientais locais, da paisagem e espaciais na estruturação de comunidades de peixes de riachos de veredas (pequenas áreas úmidas do Cerrado). As variáveis ambientais locais, após controlar o efeito do espaço, foram claramente mais importantes que aquelas obtidas na escala da paisagem. Diante das observações, conclui-se que a obtenção de dados de paisagem, em estudos que buscam variáveis ambientais relacionadas com a estruturação de comunidades locais, não deve ocorrer em detrimento da obtenção de variáveis locais (principalmente aquelas relacionadas com a estruturação dos habitats). Os resultados das três investigações deste estudo mostram o papel preponderante de filtros ambientais locais na estruturação das comunidades de peixes em riachos do Cerrado. Espécies de peixes com maiores amplitudes de nicho tendem a apresentar maiores distribuições regionais e espécies com menores tamanhos corpóreos tendem a ser localmente dominantes.
    Description: PhD
    Keywords: Peixes de riachos de cerrado ; Ecologia funcional ; Peixes de riachos de água doce ; Comunidades, Ecologia de ; Escala espaço-temporal ; Diversidade funcional ; Variáveis ambientais ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::F::Freshwater fish ; ASFA_2015::C::Communities (ecological) ; ASFA_2015::S::Stream ecology ; ASFA_2015::F::Functional analysis ; ASFA_2015::N::Niches ; ASFA_2015::D::Dispersion ; ASFA_2015::A::Abundance ; ASFA_2015::F::Filters
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 105pp.
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  • 19
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-09-07
    Description: The diversity of aquatic macrophytes provides different local conditions, containing more microhabitat than homogeneous systems, thus supporting diverse biotic communities. Considering that the diversity of these plants can affect the invertebrate community and, consequently, the associated fish diet, this study assessed the influence of macrophyte diversity on the abundance, richness, and diversity of invertebrates, and the diet of Moenkhausia forestii. Fish, invertebrates, and macrophytes were sampled in macrophyte stands with different diversities, distributed along with a 14 km extension of the coastal region of Rio Baía (Upper Paraná River floodplain). The stands were separated into low, medium and high diversity, and they all had biomass that did not differ significantly. The invertebrates associated with the macrophytes and those consumed by M. forestii were identified and counted. Differences in abundance, richness, and diversity of invertebrates between levels of macrophyte diversity (low, medium and high) were tested using an ANOVA. Differences in the composition of the M. forestii diet were tested using a PERMANOVA, and feeding selectivity was calculated using the Ivlev index. Richness, diversity, and abundance of invertebrates were greater in high diversity macrophyte stands, however, for abundance, there was no significant difference between the levels of macrophyte diversity. The diet of M. forestii differed significantly between stands, and aquatic plants were the most used resource in low diversity. Invertebrates were dominant in high diversity, while aquatic plants and invertebrates were important in medium diversity of macrophytes. These results indicate that invertebrate communities were influenced by the diversity of macrophytes since richer and more diverse communities were also associated with more diverse stands of these plants. Changes observed in the diet of M. forestii were also associated with the diversity of macrophytes. In a scenario where involving changes in the attributes of these plants, and these stands become dominated by one or a few species of macrophytes, it is expected that this will reflect on other trophic levels, even at a local scale.
    Description: A diversidade de macrófitas aquáticas proporciona condições locais distintas, de modo a conter mais micro-habitat do que sistemas homogêneos, sustentando assim comunidades associadas diversas. Considerando que a diversidade destas plantas pode influenciar a comunidade de invertebrados e, consequentemente, a dieta de peixes associados, este estudo avaliou a influência da diversidade de macrófitas sobre a abundância, riqueza e diversidade de invertebrados, e sobre a dieta de Moenkhausia forestii. Peixes, invertebrados e macrófitas foram amostrados em bancos de macrófitas com diferentes diversidades, distribuídos ao longo de 14 km de extensão da região litorânea do rio Baía (planície de inundação do alto rio Paraná). Os bancos de macrófitas foram categorizados em diversidade baixa, média e alta, e todos apresentaram biomassa que não diferiram significativamente. Os invertebrados associados à macrófitas e os consumidos por M. forestii foram identificados e contados. Diferenças na abundância, riqueza e diversidade de invertebrados entre os níveis de diversidade de macrófitas (baixa, média e alta) foram testadas por uma ANOVA. Diferenças na composição da dieta de M. forestii entre os níveis de diversidade foram avaliadas por uma PERMANOVA. A riqueza, a diversidade e a abundância de invertebrados foram maiores em bancos de macrófitas com maior diversidade, porém para a abundância não houve diferença significativa entre os níveis de diversidade de macrófitas. A dieta de M. forestii diferiu significativamente entre os bancos, sendo que vegetal foi o recurso mais utilizado em baixa diversidade de macrófitas, invertebrado foi dominante em alta diversidade e vegetal e invertebrado foram importantes em média diversidade de macrófitas. Estes resultados indicam que as comunidades de invertebrados foram influenciadas pela diversidade de macrófitas, visto que comunidades mais ricas e diversas estiveram também associadas a bancos mais diversos destas plantas. As alterações constatadas na dieta de M. forestii também estiveram associadas à diversidade de macrófitas. A espécie passou de uma dieta onívora, em bancos de baixa diversidade, para uma dieta invertívora em bancos com alta diversidade de macrófitas. Assim, em um cenário onde haja mudanças nos atributos dessas plantas, e esses bancos passem a ser dominados por uma ou poucas espécies de macrófitas, é esperado que isso se reflita para os outros níveis tróficos, ainda que em uma escala local.
    Description: Masters
    Keywords: Macrófitas aquáticas ; Comunidades, Ecologia de ; Ecologia trófica ; Diversidade ; Peixes ; Alimentação ; Nicho ; Amplitude ; ASFA_2015::M::Macrophytes ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::F::Freshwater fish ; ASFA_2015::E::Ecological diversity ; ASFA_2015::E::Ecology ; ASFA_2015::T::Trophic levels ; ASFA_2015::N::Niches ; ASFA_2015::C::Communities (ecological) ; ASFA_2015::I::Invertebrate zoology
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 32pp.
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  • 20
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-07-04
    Description: El Niño Southern Oscillation (ENSO) is a natural phenomenon that generates El Niño and La Niña events worldwide. Among the consequences caused by this climatic fluctuation, there are changes in the rainfall regime, which can trigger in times of extreme drought or extreme flood in freshwater environments, such as floodplains. The floodplain flood phases cause homogenization between the different environments, which also cause the homogenization of the fish assemblage in these floodplains. Among the rivers affected by ENSO is the Rio Paraná and the floodplain associated with its upper stretch, the upper Rio Paraná floodplain (UPRF). We aimed to study if El Niño phenomena change the functional diversity of fish in the floodplain between different environments, lakes and rivers. The results answered the hypotheses that: 1. El Niño events intensify floods in UPRF and, consequently, promote a functional homogenization of the fish assemblage; 2. Different functional guilds will be favored in times of El Niño or La Niña. The measurement of ENSO was obtained by the Oceanic Niño Index (ONI), while the hydrometric level of the upper Rio Paraná was obtained by daily measurement on a hydrometric ruler. The fish were collected with gillnets in different environments of the floodplain, lakes and rivers, being grouped in reproductive and trophic guilds, used to calculate indices of functional diversity. It was tested how ONI affects the hydrometric level of the upper Rio Paraná (Pearson's correlation); how ENSO affects the functional composition of floodplain fish (PCoA; PERMANOVA), as well as the effect of homogenization; which functional guilds are favored in El Niño or La Niña events and whether there is an additive effect of ONI and hydrometric level on the functional composition of the floodplain fish. The hydrometric level presented a positive correlation with ONI, indicating that El Niño events cause flooding in the upper Paraná River, while La Niña drought. The effect of El Niño's functional homogenization on fish was more visible in lakes, with rivers being less affected by ENSO, and floods were not intense enough to homogenize these two types of environment, this may be the same for other floodplains where ENSO acts in the same way. Fish with parental care and invertivores were favored in El Niño events, while herbivorous and piscivorous fish were favored in La Niña events. Migratory fish appears to respond one year after these climatic events, as they have a long-life cycle. The additive effect of ENSO and hydrometric level on the functional composition wasn’t found, because other regional and local factors can influence this interaction. However, even with these factors, the fish assemblage from the floodplain still responds to these climatic fluctuations, being more homogeneous in El Niño events than in La Niña events.
    Description: El Niño Oscilação Sul (El Niño Southern Oscillation – ENSO) é um fenômeno natural que gera eventos de El Niño e La Niña no mundo todo. Dentre as consequências causadas por essa oscilação climática, existem alterações no regime pluviométrico, que podem desencadear em épocas de extrema seca ou extrema cheia em ambientes de água doce, como as planícies de inundação. As fases de cheia de planícies de inundação causam uma homogeneização entre os diferentes ambientes, o que também causa a homogeneização da assembleia de peixes dessas planícies. Dentre os rios afetados por ENSO encontra-se o rio Paraná e a planície de inundação associada ao seu trecho superior, a planície de inundação do alto rio Paraná (PIARP). Estudou-se o fenômeno de El Niño e por meio da amostragem constatou-se mudanças na diversidade funcional dos peixes da planície de inundação entre diferentes ambientes, lagoas e rios. Os resultados responderam as hipóteses de que: 1. Eventos de El Niño intensifiquem cheias na PIARP e, consequentemente, provoquem uma homogeneização funcional da assembleia de peixes; 2. Diferentes guildas funcionais serão favorecidas em épocas de El Niño ou La Niña. Obteve-se a mensuração de ENSO pelo índice de ONI (Oceanic Niño Index), enquanto que o nível hidrométrico do alto rio Paraná foi obtido pela medição diária em uma régua hidrométrica. Os peixes foram coletados com redes de espera em diferentes ambientes da planície de inundação, lagoas e rios, sendo agrupados em guildas reprodutivas e alimentares, usados para calcular índices de diversidade funcional. Testou-se como o ONI afeta o nível hidrométrico do alto rio Paraná (correlação de Pearson); como o ENSO afeta a composição funcional dos peixes da planície de inundação (PCoA; PERMANOVA), bem como o efeito da homogeneização; quais guildas funcionais são favorecidas em eventos de El Niño ou La Niña e se há efeito aditivo de ONI e nível hidrométrico sobre a composição funcional dos peixes da planície. O nível hidrométrico apresentou correlação positiva com ONI, indicando que eventos de El Niño causam cheias no alto rio Paraná, enquanto La Niña, seca. O efeito da homogeneização funcional de El Niño sobre os peixes foi mais visível em lagoas, sendo que os rios foram menos afetados por ENSO, e as cheias não foram intensas o suficiente para homogeneizarem esses dois tipos de ambiente, podendo ser o mesmo para demais planícies de inundação onde ENSO age da mesma maneira. Peixes com cuidado parental e invertívoros foram favorecidos em épocas de El Niño, enquanto que, peixes herbívoros e piscívoros foram favorecidos em épocas de La Niña. Os peixes migradores aparentam responder um ano após esses eventos climáticos, por possuírem ciclo de vida longo. O efeito aditivo de ONI e nível hidrométrico sobre a composição funcional não foi encontrado, sendo que outros fatores regionais e locais podem influenciar nessa interação. Entretanto, mesmo com esses fatores a assembleia de peixes da planície de inundação ainda responde à essas oscilações climáticas, sendo mais homogênea em eventos de El Niño do que em eventos de La Niña.
    Description: Masters
    Keywords: Peixes de água doce, Assembleia de ; El Niño Oscilação Sul (ENSO) ; Diversidade e índices funcionais ; Mudanças climáticas ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::F::Freshwater fish ; ASFA_2015::A::Assemblages ; ASFA_2015::D::Diversity index ; ASFA_2015::I::Impacts ; ASFA_2015::C::Climatic changes ; ASFA_2015::E::El Nino phenomena
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 49pp.
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  • 21
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    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Publication Date: 2022-07-04
    Description: We evaluated the effects of El Niño Southern Oscillation in the fish assemblages of the upper Paraná River floodplain. Specifically, we tested if: (i) reservoirs regulate ENSO effects on the hydrometric level in the rivers that compose the plain (Rio Paraná – intensely dammed and Rio Ivinhema – not dammed); (ii) ENSO events influence the structure of the fish assemblages of the study rivers; and that (iii) the hydrometric level and the ENSO events will act synergistically on the structure of the fish assemblage of the Rio Paraná and Rio Ivinhema. ENSO data was gathered at the National Oceanic and Atmospheric Administration (NOAA), using as proxy the “Oceanic Niño Index” (ONI). Water level data were gathered from the hydrological stations located in the sampled area. Fish samplings were carried out quarterly between the years 2000 and 2018. In general, ENSO events were correlated with the hydrometric level of the Rio Paraná and Rio Ivinhema, but with lower correlation for the Rio Paraná, probably due to the effects of dams upstream the plain. The fish assemblages of the Rio Paraná and Rio Ivinhema presented distinct structures, and the ENSO events appeared to influence this differentiation. Migratory species were negatively correlated with ONI, but the greatest abundances were found one year after the events of El Niño ("Lag" of one year). Higher values of the attributes of the fish assemblages were recorded for the Rio Ivinhema, in all events of ENSO (La Niña, Neutral and El Niño), probably because it presents more pristine conditions. The hydrometric level and the ENSO events act synergistically, but distinctively in the study rivers, which should be related to their degree of impacts. Thus, the influence of ENSO in the studied area is apparently minimized, especially in the Rio Paraná, due to the flow control imposed by dams located upstream of the area.
    Description: Avaliou-se os efeitos do El Niño Oscilação Sul (El Niño Southern Oscillation-ENSO) nas assembleias de peixes da planície de inundação do alto rio Paraná. Especificamente, foram testados: (i) os reservatórios minimizam os efeitos do ENSO no nível hidrométrico nos rios que compõem a planície (rios Paraná - intensamente represado e Ivinhema - não represado); (ii) os eventos ENSO influenciam a estrutura das assembleias de peixes dos rios estudados; (iii) o nível hidrométrico e os eventos ENSO atuam sinergicamente na estrutura da assembleia de peixes dos rios Paraná e Ivinhema. Coletaram-se os dados do ENSO no National Oceanic and Atmospheric Administration (NOAA), utilizando como proxy o "Índice Niño Oceânico" (Oceanic Niño Index-ONI). Os dados do nível hidrométrico foram coletados nas estações fluviométricas localizadas na área de estudo. As amostragens de peixes transcorreram trimestralmente entre os anos 2000 e 2018. Em geral, os eventos ENSO correlacionaram-se com o nível hidrométrico dos rios Paraná e Ivinhema, mas com menor correlação para o rio Paraná, provavelmente devido aos efeitos de barragens a montante da planície. As assembleias de peixes dos respectivos rios apresentaram estruturas distintas, e os eventos ENSO pareciam influenciar essa diferenciação. As espécies migradoras possuem correlação negativa com o ONI, mas com registro de maiores abundâncias um ano após os eventos de El Niño ("Lag" de um ano). Maiores valores de riqueza e abundancia total de espécies registradas para o rio Ivinhema, em todos os eventos do ENSO (La Niña, Neutro e El Niño), provavelmente por apresentar condições mais pristinas. O nível hidrométrico e os eventos do ENSO atuam sinergicamente, mas de maneira distinta nos rios estudados, o que deve estar relacionado ao grau de impacto antrópico. Assim, a influência do ENSO na área de estudo é aparentemente minimizada, principalmente no rio Paraná, devido ao controle de vazão imposto por barragens localizadas a montante da área.
    Description: Masters
    Keywords: Peixes de água doce, Assembleia de ; El Niño Southern Oscillation (ENSO) ; Diversidade taxonômica ; Mudanças climáticas ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::F::Freshwater fish ; ASFA_2015::A::Assemblages ; ASFA_2015::E::El Nino phenomena ; ASFA_2015::C::Climatic changes ; ASFA_2015::T::Taxonomy
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 41pp.
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  • 22
    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Heaton, T. J., Koehler, P., Butzin, M., Bard, E., Reimer, R. W., Austin, W. E. N., Ramsey, C. B., Grootes, P. M., Hughen, K. A., Kromer, B., Reimer, P. J., Adkins, J., Burke, A., Cook, M. S., Olsen, J., & Skinner, L. C. Marine20-the marine radiocarbon age calibration curve (0-55,000 cal BP). Radiocarbon, 62(4), (2020): 779-820, doi:10.1017/RDC.2020.68.
    Description: The concentration of radiocarbon (14C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their 14C in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-average marine record of radiocarbon from 0–55 cal kBP and serves as a baseline for regional oceanic variation. Marine20 is intended for calibration of marine radiocarbon samples from non-polar regions; it is not suitable for calibration in polar regions where variability in sea ice extent, ocean upwelling and air-sea gas exchange may have caused larger changes to concentrations of marine radiocarbon. The Marine20 curve is based upon 500 simulations with an ocean/atmosphere/biosphere box-model of the global carbon cycle that has been forced by posterior realizations of our Northern Hemispheric atmospheric IntCal20 14C curve and reconstructed changes in CO2 obtained from ice core data. These forcings enable us to incorporate carbon cycle dynamics and temporal changes in the atmospheric 14C level. The box-model simulations of the global-average marine radiocarbon reservoir age are similar to those of a more complex three-dimensional ocean general circulation model. However, simplicity and speed of the box model allow us to use a Monte Carlo approach to rigorously propagate the uncertainty in both the historic concentration of atmospheric 14C and other key parameters of the carbon cycle through to our final Marine20 calibration curve. This robust propagation of uncertainty is fundamental to providing reliable precision for the radiocarbon age calibration of marine based samples. We make a first step towards deconvolving the contributions of different processes to the total uncertainty; discuss the main differences of Marine20 from the previous age calibration curve Marine13; and identify the limitations of our approach together with key areas for further work. The updated values for ΔR, the regional marine radiocarbon reservoir age corrections required to calibrate against Marine20, can be found at the data base http://calib.org/marine/.
    Description: We would like to thank Jeremy Oakley and Richard Bintanja for informative discussions during the development of this work. T.J. Heaton is supported by a Leverhulme Trust Fellowship RF-2019-140\9, “Improving the Measurement of Time Using Radiocarbon”. M Butzin is supported by the German Federal Ministry of Education and Research (BMBF), as Research for Sustainability initiative (FONA); www.fona.de through the PalMod project (grant numbers: 01LP1505B, 01LP1919A). E. Bard is supported by EQUIPEX ASTER-CEREGE and ANR CARBOTRYDH. Meetings of the IntCal Marine Focus group have been supported by Collège de France. Data are available on the PANGAEA database at doi:10.159/ANGAEA.914500.
    Keywords: Bayesian modeling ; calibration ; carbon cycle ; computer model ; marine environment
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 23
    Publication Date: 2020-12-21
    Description: Subglacial sediments have the potential to reveal information about the controls on glacier flow, changes in ice-sheet history and characterise life in those environments. Retrieving sediments from beneath the ice, through hot water drilled access holes at remote field locations, present many challenges. Motivated by the need to minimise weight, corer diameter and simplify assembly and operation, British Antarctic Survey, in collaboration with UWITEC, developed a simple mechanical percussion corer. At depths over 1000 m however, manual operation of the percussion hammer is compromised by the lack of clear operator feedback at the surface. To address this, we present a new auto-release-recovery percussion hammer mechanism that makes coring operations depth independent and improves hammer efficiency. Using a single rope tether for both the corer and hammer operation, this modified percussion corer is relatively simple to operate, easy to maintain, and has successfully operated at a depth of 〉2130 m.
    Print ISSN: 0260-3055
    Electronic ISSN: 1727-5644
    Topics: Geography , Geosciences
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  • 24
    Publication Date: 2020-12-22
    Description: The Japanese second deep ice coring project was carried out at Dome Fuji, Antarctica. Following the drilling of the pilot hole in 2001, deep ice core drilling led by the Japanese Antarctic Research Expedition (JARE) was conducted over four austral summer seasons, beginning with the 2003/04 season and reached a depth of 3035.22 m near the bedrock in January 2007. The new drill was designed and developed with the goals of (1) solving the problems encountered during the first JARE deep coring drill and (2) achieving more efficient drilling. In particular, the maximum core length that can be drilled at one time was increased from 2.30 m to 3.84 m and the chip storage efficiency was enhanced by a special pipe with many small holes. This paper gives an outline of the improved drilling system, the progress of drilling and various drilling data.
    Print ISSN: 0260-3055
    Electronic ISSN: 1727-5644
    Topics: Geography , Geosciences
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  • 25
    Publication Date: 2020-12-21
    Description: Three holes were drilled to the bed of Rutford Ice Stream, through ice up to 2154 m thick, to investigate the basal processes and conditions associated with fast ice flow and the glacial history of the West Antarctic Ice Sheet. A narrative of the drilling, measuring and sampling activities, as well as some preliminary results and initial interpretations of subglacial conditions, is given. These were the deepest subglacial access holes ever drilled using the hot-water drilling method. Samples of bed and englacial sediments were recovered, and a number of instruments were installed in the ice column and the bed. The ice–bed interface was found to be unfrozen, with an existing, well-developed subglacial hydrological system at high pressure, within ~1% of the ice overburden. The bed itself comprises soft, water-saturated sediments, consistent with previous geophysical interpretations. Englacial sediment quantity varies significantly between two locations ~2 km apart, and possibly over even shorter (~20 m) distances. Difficulties and unusual observations encountered while connecting to the subglacial hydrological system in one hole possibly resulted from the presence of a large clast embedded in the bottom of the ice.
    Print ISSN: 0260-3055
    Electronic ISSN: 1727-5644
    Topics: Geography , Geosciences
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  • 26
    Publication Date: 2020-11-03
    Description: A series of new synthetic armored cables were developed and tested to ensure that they were suitable for use with the RECoverable Autonomous Sonde (RECAS), which is a newly designed freezing-in thermal ice probe. The final version of the cable consists of two concentric conductors that can be used as the power and signal lines. Two polyfluoroalkoxy jackets are used for electrical insulation (one for insulation between conductors, and the other for insulation of the outer conductor). The outer insulation layer is coated by polyurethane jacket to seal the connections between the cable and electrical units. The 0.65 mm thick strength member is made from aramid fibers woven together. To hold these aramid fibers in place, a sheathing layer was produced from a polyamide fabric cover net. The outer diameter of the final version of the cable is ~6.1 mm. The permissible bending radius is as low as 17–20 mm. The maximal breaking force under straight tension is ~12.2 kN. The cable weight is only ~0.061 kg m−1. The mechanical and electrical properties and environmental suitability of the cable were determined through laboratory testing and joint testing with the probe.
    Print ISSN: 0260-3055
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  • 27
    Publication Date: 2020-11-11
    Description: Ever since the first deep ice cores were drilled, it has been a challenge to determine their original, in-situ orientation. In general, the orientation of an ice core is lost as the drill is free to rotate during transport to the surface. For shallow ice cores, it is usually possible to match the adjacent core breaks, which preserves the orientation of the ice column. However, this method fails for deep ice cores, such as the EastGRIP ice core in Northeast Greenland. We provide a method to reconstruct ice core orientation using visual stratigraphy and borehole geometry. As the EastGRIP ice core is drilled through the Northeast Greenland Ice Stream, we use information about the directional structures to perform a full geographical re-orientation. We compared the core orientation with logging data from core break matching and the pattern of the stereographic projections of the crystals’ c-axis orientations. Both comparisons agree very well with the proposed orientation method. The method works well for 441 out of 451 samples from a depth of 1375–2120 m in the EastGRIP ice core. It can also be applied to other ice cores, providing a better foundation for interpreting physical properties and understanding the flow of ice.
    Print ISSN: 0260-3055
    Electronic ISSN: 1727-5644
    Topics: Geography , Geosciences
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