ALBERT

Description: Harmful algal blooms (HABs) are globally increasing in number and spatial extent. However, their propagation dynamics along environmental gradients and the associated interplay of abiotic factors and biotic interactions are still poorly understood. In this study, a nutrient gradient was established in a linear meta‐ecosystem setup of five interconnected flasks containing an artificially assembled phytoplankton community. The harmful dinoflagellate Alexandrium catenella was introduced into different positions along the nutrient gradient to investigate dispersal and spatial community dynamics. Overall, total algal biovolume increased, while community evenness decreased with increasing nutrient concentrations along the gradient. Alexandrium was able to disperse through all flasks. On the regional scale, diatoms dominated the community, whereas on the local scale the dinoflagellate showed higher contributions at low nutrient concentrations and dominated the community at the lowest nutrient concentration, but only when initiated into this flask. A control treatment without dispersal revealed an even stronger dominance of Alexandrium at the lowest nutrient concentration, indicating that dispersal and the associated nutrient exchange may weaken dinoflagellate dominance under low nutrient conditions. This study presents a first approach to experimentally investigate spatial dynamics and ecological interactions of a harmful dinoflagellate along an environmental gradient in a meta‐ecosystem setup, which has the potential to substantially enhance our understanding of the relevance of dispersal for HAB formation and propagation in combination with local environmental factors.

Description: Volkswagen Foundation http://dx.doi.org/10.13039/501100001663

Description: Microbial organic matter decomposition is a critical ecosystem function, which can be negatively affected by chemicals. Although the majority of organic matter is stored in sediments, the impact of chemicals has exclusively been studied in benthic systems. To address this knowledge gap, we assessed the impact of a fungicide mixture at three concentrations on the decomposition of black alder leaves in the benthic and hyporheic zone. We targeted two sediment treatments characterized by fine and coarse grain sizes (1–2 vs. 2–4 mm). Besides microbial communities' functioning (i.e., decomposition), we determined their structure through microbial biomass estimates and community composition. In absence of fungicides, leaf decomposition, microbial biomass estimates and fungal sporulation were lower in the hyporheic zone, while the importance of bacteria was elevated. Leaf decomposition was reduced (40%) under fungicide exposure in fine sediment with an effect size more than twice as high as in the benthic zone (15%). These differences are likely triggered by the lower hydraulic conductivity in the hyporheic zone influencing microbial dispersal as well as oxygen and nutrient fluxes. Since insights from the benthic zone are not easily transferable, these results indicate that the hyporheic zone requires a higher recognition with regard to ecotoxicological effects on organic matter decomposition.

Description: German Research Foundation, Project AQUA‐REG http://dx.doi.org/10.13039/501100001659

Description: Nutrients limiting phytoplankton growth in the ocean are a critical control on ocean productivity and can underpin predicted responses to climate change. The extensive western subtropical North Pacific is assumed to be under strong nitrogen limitation, but this is not well supported by experimental evidence. Here, we report the results of 14 factorial nitrogen–phosphorus–iron addition experiments through the Philippine Sea, which demonstrate a gradient from nitrogen limitation in the north to nitrogen–iron co‐limitation in the south. While nitrogen limited sites responded weakly to nutrient supply, co‐limited sites bloomed with up to ~60‐fold increases in chlorophyll a biomass that was dominated by initially undetectable diatoms. The transition in limiting nutrients and phytoplankton growth capacity was driven by a gradient in deep water nutrient supply, which was undetectable in surface concentration fields. We hypothesize that this large‐scale phytoplankton response gradient is both climate sensitive and potentially important for regulating the distribution of predatory fish.

Description: National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809

Description: In 1883, Theodor Wilhelm Engelmann, a German scientist, wrote his essay “color and assimilation” (Ger.: “Farbe und Assimilation”) describing the state of the art in photosynthesis research, his recent findings, and further assumptions based upon his presented results. Nearly 140 years later, many of his assumptions were proven correct. By his still well‐known bacteria experiments using aerotactic, heterotrophic bacteria, he identified the chloroplasts as the location in which photosynthesis and oxygen production takes place. Furthermore, by evaluating the effects of different light spectra, he constructed the first action spectra that demonstrated the implication of the “green gap” of chlorophylls. He further posited that accessory photosynthetic pigments existed to extend the absorption range of chlorophyll. Although infrequently cited, his work was foundational for current ecological research of the vertical appearance of algae species within the underwater gradient in light spectrum due to specific harvesting of different light spectra, hence complementary chromatic adaptation of communities. This short retrospective highlights this piece of literature that represents an early step toward our current understanding of ecological competition for light spectra.

Description: Inland waters receive and process large amounts of colored organic matter from the terrestrial surroundings. These inputs dramatically affect the chemical, physical, and biological properties of water bodies, as well as their roles as global carbon sinks and sources. However, manipulative studies, especially at ecosystem scale, require large amounts of dissolved organic matter with optical and chemical properties resembling indigenous organic matter. Here, we compared the impacts of two leonardite products (HuminFeed and SuperHume) and a freshly derived reverse osmosis concentrate of organic matter in a set of comprehensive mesocosm‐ and laboratory‐scale experiments and analyses. The chemical properties of the reverse osmosis concentrate and the leonardite products were very different, with leonardite products being low and the reverse osmosis concentrate being high in carboxylic functional groups. Light had a strong impact on the properties of leonardite products, including loss of color and increased particle formation. HuminFeed presented a substantial impact on microbial communities under light conditions, where bacterial production was stimulated and community composition modified, while in dark potential inhibition of bacterial processes was detected. While none of the browning agents inhibited the growth of the tested phytoplankton Gonyostomum semen, HuminFeed had detrimental effects on zooplankton abundance and Daphnia reproduction. We conclude that the effects of browning agents extracted from leonardite, particularly HuminFeed, are in sharp contrast to those originating from terrestrially derived dissolved organic matter. Hence, they should be used with great caution in experimental studies on the consequences of terrestrial carbon for aquatic systems.

Description: Marie Curie International Outgoing Fellowship

Description: Swedish Research Council Formas http://dx.doi.org/10.13039/501100001862

Description: Knut and Alice Wallenberg Foundation http://dx.doi.org/10.13039/501100004063

Description: The interaction between the land surface and the atmosphere is a crucial driver of atmospheric processes. Soil moisture and precipitation are key components in this feedback. Both variables are intertwined in a cycle, that is, the soil moisture – precipitation feedback for which involved processes and interactions are still discussed. In this study the soil moisture – precipitation feedback is compared for the sempiternal humid Ammer catchment in Southern Germany and for the semiarid to subhumid Sissili catchment in West Africa during the warm season, using precipitation datasets from the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), from the German Weather Service (REGNIE) and simulation datasets from the Weather Research and Forecasting (WRF) model and the hydrologically enhanced WRF‐Hydro model. WRF and WRF‐Hydro differ by their representation of terrestrial water flow. With this setup we want to investigate the strength, sign and variables involved in the soil moisture – precipitation feedback for these two regions. The normalized model spread between the two simulation results shows linkages between precipitation variability and diagnostic variables surface fluxes, moisture flux convergence above the surface and convective available potential energy in both study regions. The soil moisture – precipitation feedback is evaluated with a classification of soil moisture spatial heterogeneity based on the strength of the soil moisture gradients. This allows us to assess the impact of soil moisture anomalies on surface fluxes, moisture flux convergence, convective available potential energy and precipitation. In both regions the amount of precipitation generally increases with soil moisture spatial heterogeneity. For the Ammer region the soil moisture – precipitation feedback has a weak negative sign with more rain near drier patches while it has a positive signal for the Sissili region with more rain over wetter patches. At least for the observed moderate soil moisture values and the spatial scale of the Ammer region, the spatial variability of soil moisture is more important for surface‐atmosphere interactions than the actual soil moisture content. Overall, we found that soil moisture heterogeneity can greatly affect the soil moisture – precipitation feedback.

Description: WRF and WRF‐hydro model simulations are used to determine the sign and analyse the mechanisms of the soil moisture ‐ precipitation feedback for the sempiternal humid Ammer catchment in Southern Germany and for the semiarid to subhumid Sissili catchment in West Africa during the warm season. The generation of moist convection is favoured over surfaces with moderately high soil moisture gradients in the Ammer region, while for the Sissili region the location of precipitation tends to be related to areas with high soil moisture gradients. For the Ammer region the soil moisture – precipitation feedback has a weak negative sign with more rain near drier patches while it has a positive signal for the Sissili region with more rain over wetter patches.

Description: Untersuchung des Klimas des südlichen Afrikas – ein Brückenschlag vom frühen Holozän bis heute

Description: Transregional Collaborative Research Center

Description: Light is a fundamental resource for phytoplankton. To utilize the available light, most phytoplankton species possess pigments in taxon‐specific combinations and quantities, which in turn result in a specific use of certain wavelengths. This optimizes the light use efficiency, allows for a complementary use of light, and may be an additional driver for community structure. While the effects of light intensity on phytoplankton biomass production and community composition have been intensively studied, here we focused on the effects of specific light spectrum quality (thus light color) on a natural phytoplankton community. In a controlled mesocosm experiment we reduced the supplied wavelength range to its blue, green, or red part of the light spectrum and compared the responses of each treatment to a full spectrum control over 28 d. Highest community growth rates were observed under blue, lowest under red light. Light absorption by the communities showed adaptation toward the supplied wavelength range. Community composition was significantly affected by light quality treatments, driven by Bacillariophyta and Chlorophyta, whereas pigment composition was not. Furthermore, lower species richness but higher evenness occurred when communities were exposed to red light compared to the full spectrum. We expected the response of phytoplankton communities to changes in the light spectrum to be driven by a combination of species sorting and pigment acclimation; however, the effect of species sorting turned out to be stronger. Our study showed that, even if species might acclimate, changes in the available light spectrum affect primary production and phytoplankton community composition.

Description: Nitrate monitoring is commonly conducted with low‐spatial resolution, only at the outlet or at a small number of selected locations. As a result, the information about spatial variations in nitrate export and its drivers is scarce. In this study, we present results of high‐spatial resolution monitoring conducted between 2012 and 2017 in 65 sub‐catchments in an Alpine mesoscale river catchment characterized by a land‐use gradient. We combined stable isotope techniques with Bayesian mixing models and geostatistical methods to investigate nitrate export and its main drivers, namely, microbial N turnover processes, land use and hydrological conditions. In the investigated sub‐catchments, mean values of NO3− concentrations and its isotope signatures (δ15NNO3 and δ18ONO3) varied from 2.6 to 26.7 mg L−1, from −1.3‰ to 13.1‰, and from −0.4‰ to 10.1‰, respectively. In this study, land use was an important driver for nitrate export. Very strong and strong positive correlations were found between percentages of agricultural land cover and δ15NNO3, and NO3− concentration, respectively. Mean proportional contributions of NO3− sources varied spatially and seasonally, and followed land‐use patterns. The mean contribution of manure and sewage was much higher in the catchments characterized by a high percentage of agricultural and urban land cover comparing to forested sub‐catchments. Specific NO3− loads were strongly correlated with specific discharge and moderately correlated with NO3− concentrations. The nitrate isotope and concentration analysis results suggest that nitrate from external sources is stored and accumulated in soil storage pools. Nitrification of reduced nitrogen species in those pools plays the most important role for the N‐dynamics in the Erlauf river catchment. Consequently, nitrification of reduced N sources was the main nitrate source except for a number of sub‐catchments dominated by agricultural land use. In the Erlauf catchment, denitrification plays only a minor role in controlling NO3− export on a regional scale.

Description: We integrated results of the BMM with informative priors and top‐kriging. Reduced N stored in soil is an important source for stream N in a mesoscale catchment. Manure and sewage is the main NO3− source in agricultural sub‐catchments. Denitrification played only a minor role in controlling regional scale NO3− export.

Description: Complex networks of both natural and engineered flow paths control the hydrology of streams in major cities through spatio‐temporal variations in connection and disconnection of diverse water sources. We used spatially extensive and temporally intensive sampling of water stable isotopes to disentangle the hydrological sources of the heavily urbanized Panke catchment (~220 km2) in the north of Berlin, Germany. The isotopic data enabled us to partition stream water sources across the catchment using a Bayesian mixing analysis. The upper part of the catchment streamflow is dominated by groundwater (~75%) from gravel aquifers. In dry summer periods, streamflow becomes intermittent in the upper catchment, possibly as a result of local groundwater abstractions. Storm drainage dominates the responses to precipitation events. Although such events can dramatically change the isotopic composition of the upper stream network, storm drainage only accounts for 10%–15% of annual streamflow. Moving downstream, subtle changes in sources and isotope signatures occur as catchment characteristics vary and the stream is affected by different tributaries. However, effluents from a wastewater treatment plant (WWTP), serving 700,000 people, dominate stream flow in the lower catchment (~90% of annual runoff) where urbanization effects are more dramatic. The associated increase in sealed surfaces downstream also reduces the relative contribution of groundwater to streamflow. The volume and isotopic composition of storm runoff is again dominated by urban drainage, though in the lower catchment, still only about 10% of annual runoff comes from storm drains. The study shows the potential of stable water isotopes as inexpensive tracers in urban catchments that can provide a more integrated understanding of the complex hydrology of major cities. This offers an important evidence base for guiding the plans to develop and re‐develop urban catchments to protect, restore, and enhance their ecological and amenity value.

Description: Intermittent urban stream. Groundwater and waste water dominance. High temporal and spatial stable isotope dataset. End member mixing analysis. Water import.

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

Description: Einstein Stiftung Berlin http://dx.doi.org/10.13039/501100006188

Description: Leverhulme Trust http://dx.doi.org/10.13039/501100000275

Description: Fjords are recognized as hotspots of organic carbon (OC) burial in the coastal ocean. In fjords with glaciated catchments, glacier discharge carries large amounts of suspended matter. This sedimentary load includes OC from bedrock and terrigenous sources (modern vegetation, peat, soil deposits), which is either buried in the fjord or remineralized during export, acting as a potential source of CO2 to the atmosphere. In sub‐Antarctic South Georgia, fjord‐terminating glaciers have been retreating during the past decades, likely as a response to changing climate conditions. We determine sources of OC in surface sediments of Cumberland Bay, South Georgia, using lipid biomarkers and the bulk 14C isotopic composition, and quantify OC burial at present and for the time period of documented glacier retreat (between 1958 and 2017). Petrogenic OC is the dominant type of OC in proximity to the present‐day calving fronts (60.4 ± 1.4% to 73.8 ± 2.6%) and decreases to 14.0 ± 2.7% outside the fjord, indicating that petrogenic OC is effectively buried in the fjord. Beside of marine OC, terrigenous OC comprises 2.7 ± 0.5% to 7.9 ± 5.9% and is mostly derived from modern plants and Holocene peat and soil deposits that are eroded along the flanks of the fjord, rather than released by the retreating fjord glaciers. We estimate that the retreat of tidewater glaciers between 1958 and 2017 led to an increase in petrogenic carbon accumulation of 22% in Cumberland West Bay and 6.5% in Cumberland East Bay, suggesting that successive glacier retreat does not only release petrogenic OC into the fjord, but also increases the capacity of OC burial.

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

Description: Cell size is a master trait in the functional ecology of phytoplankton correlating with numerous morphological, physiological, and life‐cycle characteristics of species that constrain their nutrient use, growth, and edibility. In contrast to well‐known spatial patterns in cell size at macroecological scales or temporal changes in experimental contexts, few data sets allow testing temporal changes in cell sizes within ecosystems. To analyze the temporal changes of intraspecific and community‐wide cell size, we use the phytoplankton data derived from the Lower Saxony Wadden Sea monitoring program, which comprises sample‐ and species‐specific measurements of cell volume from 1710 samples collected over 14 yr. We find significant reductions in both the cell volume of most species and the weighted mean cell size of communities. Mainly diatoms showed this decline, whereas the size of dinoflagellates seemed to be less responsive. The magnitude of the trend indicates that cell volumes are about 30% smaller now than a decade ago. This interannual trend is overlayed by seasonal cycles with smaller cells typically observed in summer. In the subset of samples including environmental conditions, small community cell size was strongly related to high temperatures and low total phosphorus concentration. We conclude that cell size captures ongoing changes in phytoplankton communities beyond the changes in species composition. In addition, based on the changes in species biovolumes revealed by our analysis, we warn that using standard cell size values in phytoplankton assessment will not only miss temporal changes in size, but also lead to systematic errors in biomass estimates over time.

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

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

Description: Interreg V A program Deutschland‐Nederland of the European Union

Description: Niedersächsisches Ministerium für Wissenschaft und Kultur http://dx.doi.org/10.13039/501100010570

Description: https://doi.org/10.5281/zenodo.5799263

Description: The regional terrestrial water cycle is strongly altered by human activities. Among them, reservoir regulation is a way to spatially and temporally allocate water resources in a basin for multi‐purposes. However, it is still not sufficiently understood how reservoir regulation modifies the regional terrestrial‐ and subsequently, the atmospheric water cycle. To address this question, the representation of reservoir regulation into the terrestrial component of fully coupled regional Earth system models is required. In this study, an existing process‐based reservoir network module is implemented into NOAH‐HMS, that is, the terrestrial component of an atmospheric–hydrologic modelling system, namely, the WRF‐HMS. It allows to quantitatively differentiate role of reservoir regulation and of groundwater feedback in a simulated ground‐soil‐vegetation continuum. Our study focuses on the Poyang Lake basin, where the largest freshwater lake of China and reservoirs of different sizes are located. As compared to streamflow observations, the newly extended NOAH‐HMS slightly improves the streamflow and streamflow duration curves simulation for the Poyang Lake basin for the period 1979–1986. The inclusion of reservoir regulation leads to major changes in the simulated groundwater recharges and evaporation from reservoirs at local scale, but has minor effects on the simulated soil moisture and surface runoff at basin scale. The performed groundwater feedback sensitivity analysis shows that the strength of the groundwater feedback is not altered by the consideration of reservoir regulation. Furthermore, both reservoir regulation and groundwater feedback modify the partitioning of the simulated evapotranspiration, thus affecting the atmospheric water cycle in the Poyang Lake region. This finding motivates future research with our extended fully coupled atmospheric–hydrologic modelling system by the community.

Description: An existing process‐based reservoir network module is implemented into the terrestrial component NOAH‐HMS of the atmospheric–hydrologic modelling system WRF‐HMS. The inclusion of reservoir regulation leads to major changes in the simulated groundwater recharges and evaporation from reservoirs at local scale, but does not alter the strength of the groundwater feedback. Reservoir regulation and groundwater feedback play different roles in modifying the regional terrestrial water cycle for the Poyang Lake basin, particularly with respect to the partitioning of the simulated evapotranspiration.

Description: German Federal Ministry of Science and Education

Description: German Research Foundation http://dx.doi.org/10.13039/501100001659

Description: National Key R&D Program of China

Description: National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809

Description: The two small research catchments Obere Brachtpe (2.6 km2; 50.989986, 7.752013) and Bohlmicke (1 km2, 51.079319, 7.892988) are located in the Rhenish Massif, a low mountain range in Germany. Land use in both catchments is dominated by pasture land, spruce stands and mixed forests. Mean annual temperature is 9.1°C, and mean annual total precipitation is 1250 mm, with 15%–20% of the annual precipitation falling as snow. The geology is characterized by sandy silty clay shale from the Lower and Middle Devonian. Loamy Cambisols derived from periglacial slope deposits, complemented by Leptosols and Stagnosols, are the most prominent soils in the catchments. Long‐term hydrological datasets of precipitation, throughfall, discharge, groundwater levels and soil moisture (at different soil depths) in a high temporal and spatial resolution are available for further scientific analysis. Both catchments were monitored within the time period 1999 and 2009, in order to understand how the antecedent soil moisture, stratified soils (periglacial cover beds) and topography (slope form) impacted the subsurface connectivity, and the subsurface stormflow generation ‐ a dominant runoff generation process in humid mountainous catchments. Detailed physically based investigations on runoff processes were carried out, and the obtained results helped to better understand subsurface stormflow generation and subsurface connectivity dynamics. The process knowledge gained, which was presented at several conferences, as well as publications, was the basis for the discussion of open questions within the scientific network ‘Subsurface Stormflow ‐ A well‐recognized, but still challenging process in Catchment Hydrology’ (2016–2021), and the research unit ‘Fast and invisible: conquering subsurface stormflow through an interdisciplinary multisite approach’ (2022–2025), both financed by the German Research Foundation (DFG).

Description: Long‐term hydrological datasets of precipitation, throughfall, discharge, groundwater levels and soil moisture (at different soil depths) in a high temporal and spatial resolution are available of the two small catchments Obere Brachtpe (2.6 km²) and Bohlmicke (1 km²) (Germany). Both catchments have been monitored in order to understand how the antecedent soil moisture, stratified soils (periglacial cover beds) and topography (slope form) impacted the subsurface connectivity and the subsurface stormflow generation in humid mountainous catchments.

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

Description: Statistical and climate models are frequently used for biodiversity projections under future climatic changes, but their predictive capacity for freshwater plankton may vary among different species and community metrics. Here, we used random forests to model plankton species and community metrics as a function of biological, climatic, physical, and chemical data from long‐term (2000–2017) monitoring data collected from Lake Müggelsee Berlin, Germany. We (1) compared the predictability of well‐known lake plankton metric types (biomass, abundance, taxonomic diversity, Shannon diversity, Simpson diversity, evenness, taxonomic distinctness, and taxonomic richness) and (2) assessed how the relative influence of different environmental drivers varies across lake plankton metric models. Overall, the metric predictability was highest for biomass and abundance followed by taxonomic richness. The biomass of dominant phytoplankton taxonomic groups such as cyanobacteria (adjusted‐R2 = 0.53) and the abundance of dominant zooplankton taxonomic groups such as rotifers (adjusted‐R2 = 0.59) and daphnids (adjusted‐R2 = 0.51) were more predictable than other metric types. The plankton metric predictability increased when grouping phytoplankton species according to their functional traits (adjusted‐R2 = 0.37 ± 0.14, mean ± SD, n = 36 functional groups) compared to higher taxonomic units (adjusted‐R2 = 0.25 ± 0.15, n = 22 taxonomic groups). Light, nutrients, water temperature, and seasonality for phytoplankton and food resources for zooplankton were the main drivers of both taxonomic and functional groups, giving confidence that our models captured the expected major environmental drivers. Our quantitative analyses highlight the multidimensionality of lake planktonic responses to environmental drivers and have implications for our capacity to select appropriate metrics for forecasting the future of lake ecosystems under global change scenarios.

Description: European Union's Horizon 2020 Research and Innovation Programme

Description: Belmont Forum

Description: BiodivERsA

Description: LimnoSCenES

Description: Many lake ecosystems that have been severely disturbed by eutrophication, have also experienced large human efforts to restore “natural” conditions. However, the trajectories and the extent of recovery of these lake ecosystems are still poorly understood. In many shallow lakes, recovery was often delayed and counter‐clockwise hysteretic. Here, we study recovery and ecosystem trajectories in a large and deep lake using diatom remains in sediment cores and time series of phosphorus concentrations. We identified four periods of diatom community change: slow change during early eutrophication, thereafter a short period of rapid change after the 1950s, followed by community stability from the 1960s to the mid‐1980s, and finally a recovery phase until 2010. Diatom community structure responded quickly and in a saturating way to increasing phosphorus concentrations, but also fast to phosphorus decline. Hence, diatom community dynamics did not show counter‐clockwise hysteresis but was characterized by a high degree of recovery and clock‐wise hysteresis (CWH). We suggest that CWH in response to eutrophication and recovery is a typical and previously overlooked feature of deep lakes, which results from a more rapid change of average nutrient concentrations and thus productivity in the epilimnion compared to average nutrient concentrations across the entire water column. Such nonlinear and hysteretic responses to changing nutrients need to be considered when analyzing the effects of other stressors such as climate warming on ecosystem dynamics to prevent erroneous attribution of ecosystem change to other stressors instead of nutrient change.

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

Description: European Regional Development Fund http://dx.doi.org/10.13039/501100008530

Description: The end of the polar night with the concurrent onset of photosynthetic biomass production ultimately leads to the spring bloom, which represents the most important event of primary production for the Arctic marine ecosystem. This dataset shows, for the first time, significant in situ biomass accumulation during the dark–light transition in the high Arctic, as well as the earliest recorded positive net primary production rates together with constant chlorophyll a‐normalized potential for primary production through winter and spring. The results indicate a high physiological capacity to perform photosynthesis upon re‐illumination, which is in the same range as that observed during the spring bloom. Put in context with other data, the results of this study indicate that also active cells originating from the low winter standing stock in the water column, rather than solely resting stages from the sediment, can seed early spring bloom assemblages.

Description: In‐depth understanding of the potential implications of climate change is required to guide decision‐ and policy‐makers when developing adaptation strategies and designing infrastructure suitable for future conditions. Impact models that translate potential future climate conditions into variables of interest are needed to create the causal connection between a changing climate and its impact for different sectors. Recent surveys suggest that the primary strategy for validating such models (and hence for justifying their use) heavily relies on assessing the accuracy of model simulations by comparing them against historical observations. We argue that such a comparison is necessary and valuable, but not sufficient to achieve a comprehensive evaluation of climate change impact models. We believe that a complementary, largely observation‐independent, step of model evaluation is needed to ensure more transparency of model behavior and greater robustness of scenario‐based analyses. This step should address the following four questions: (1) Do modeled dominant process controls match our system perception? (2) Is my model's sensitivity to changing forcing as expected? (3) Do modeled decision levers show adequate influence? (4) Can we attribute uncertainty sources throughout the projection horizon? We believe that global sensitivity analysis, with its ability to investigate a model's response to joint variations of multiple inputs in a structured way, offers a coherent approach to address all four questions comprehensively. Such additional model evaluation would strengthen stakeholder confidence in model projections and, therefore, into the adaptation strategies derived with the help of impact models.

Description: A comprehensive evaluation of climate change impact models combining both observation‐based and response‐based strategies.

Description: This article is categorized under: Climate Models and Modeling 〉 Knowledge Generation with Models Assessing Impacts of Climate Change 〉 Evaluating Future Impacts of Climate Change

Description: Alexander von Humboldt‐Stiftung http://dx.doi.org/10.13039/100005156

Description: Engineering and Physical Sciences Research Council http://dx.doi.org/10.13039/501100000266

Description: Bacteria play a key role in sustaining the chemodiversity of marine dissolved organic matter (DOM), yet there is limited direct evidence of a major contribution of bacterial exometabolites to the DOM pool. This study tests whether molecular formulae of intact exometabolites can be detected in natural DOM via untargeted Fourier‐transform ion cyclotron resonance mass spectrometry (FT‐ICR‐MS). We analyzed a series of quantitative mixtures of solid‐phase extracted DOM from the deep ocean, of a natural microbial community and selected model strains of marine bacteria. Under standard instrument settings (200 broadband scans, mass range 92–1000 Da), 77% of molecular formulae were shared between the mesocosm and marine DOM. However, there was 〈 10% overlap between pure bacterial exometabolome with marine DOM, and in mixing ratios closest to mimicking natural environments (1% bacterial DOM, 99% marine DOM), only 4% of the unique bacterial exometabolites remained detectable. Further experiments with the bacterial exometabolome DOM mixtures using enhanced instrument settings resulted in increased detection of the exometabolites at low concentrations. At 1000 and 10,000 accumulated scans, 23% and 29% of the unique molecular formulae were detectable at low concentrations, respectively. Moreover, windowing a specific mass range encompassing a representative fraction of exometabolites tripled the number of unique detected formulae at low concentrations. Routine FT‐ICR‐MS settings are thus not always sufficient to distinguish bacterial exometabolome patterns from a seawater DOM background. To observe these patterns at higher sensitivity, we recommend a high scan number coupled with windowing a characteristic region of the molecular fingerprint.

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

Description: The latest version of the Soil and Water Assessment Tool (SWAT+) features several improvements compared with previous versions of the model, for example, the definition of landscape units that allow for a better representation of spatio‐temporal dynamics. To evaluate the new model capabilities in lowland catchments characterized by near‐surface groundwater tables and extensive tile drainage, we assess the performance of two SWAT+ model setups in comparison to a setup based on a previous SWAT model version (SWAT3S with a modified three groundwater storage model) in the Kielstau catchment in Northern Germany. The Kielstau catchment has an area of about 50 km2, is dominated by agricultural land use, and has been thoroughly monitored since 2005. In both SWAT+ setups, the catchment is divided into upland areas and floodplains, but in the first SWAT+ model setup, runoff from the hydrologic response units is summed up at landscape unit level and added directly to the stream. In the second SWAT+ model setup, runoff is routed across the landscape before it reaches the streams. Model results are compared with regard to (i) model performance for stream flow at the outlet of the catchment and (ii) aggregated as well as temporally and spatially distributed water balance components. All three model setups show a very good performance at the catchment outlet. In comparison to a previous version of the SWAT model that produced more groundwater flow, the SWAT+ model produced more tile drainage flow and surface runoff. Results from the new SWAT+ model confirm that the representation of routing processes from uplands to floodplains in the model further improved the representation of hydrological processes. Particularly, the stronger spatial heterogeneity that can be related to characteristics of the landscape, is very promising for a better understanding and model representation of hydrological fluxes in lowland areas. The outcomes of this study are expected to further prove the applicability of SWAT+ and provide useful information for future model development.

Description: The model performance of all three model setups was very good, but the SWAT+ model setup with runoff routing between landscape units performed best. Moreover, the SWAT+ model applications predicted a greater spatial heterogeneity of the water balance components. The representation of hydrological fluxes particularly with regard to groundwater flow, surface runoff, and tile drainage flow differed considerably between the SWAT and SWAT+ model setups.

Description: Pelagic bacteria can be classified into free‐living and particle‐attached life modes, which either dwell in the water column or attach to suspended particles. Bacteria with a generalist life style, however, can actively shift between these two habitats. Globally increasing densities of natural and artificial particles enhance habitat heterogeneity, with potential consequences for system stability and trophic transfer through aquatic food webs. To better decipher the dynamics of microbial communities, we investigated the influence of adaptive vs. fixed habitat choice on species coexistence for a simplified bacterial community by analyzing a corresponding food web model, consisting of two specialist bacterial prey species (free and attached), a generalist bacterial prey species with the ability to shift between both habitats, and two protist predators, specialized on either water or particle compartment. For simplicity we assume a shared resource pool, considering particles only for colonization but not as a source for nutrients or carbon, that is, inert particles like microplastics or inorganic sediments. The model predicts coexistence on a cyclic attractor between fixed and flexible bacteria, if the costs for adaptive habitat choice can be balanced by adaptation speed. The presence of adaptive prey dampens predator–prey cycle amplitudes, contributing to system stabilization resulting in higher mean predator biomass compared to specialist prey only. Thus, in pelagic microbial systems, flexible habitat choice at the prey level has important implications for system stability and magnitude of energy flow through the microbial loop.

Description: German Ministry of Education and Science

Description: German Science Foundation (DFG)

Description: Greenhouse gas fluxes (CO2, CH4, and N2O) from African streams and rivers are under‐represented in global datasets, resulting in uncertainties in their contributions to regional and global budgets. We conducted year‐long sampling of 59 sites in a nested‐catchment design in the Mara River, Kenya in which fluxes were quantified and their underlying controls assessed. We estimated annual basin‐scale greenhouse gas emissions from measured in‐stream gas concentrations, modeled gas transfer velocities, and determined the sensitivity of up‐scaling to discharge. Based on the total annual CO2‐equivalent emissions calculated from global warming potentials (GWP), the Mara basin was a net greenhouse gas source (294 ± 35 Gg CO2 eq yr−1). Lower‐order streams (1–3) contributed 81% of the total fluxes, and higher stream orders (4–8) contributed 19%. Cropland‐draining streams also exhibited higher fluxes compared to forested streams. Seasonality in stream discharge affected stream widths (and stream area) and gas exchange rates, strongly influencing the basin‐wide annual flux, which was 10 times higher during the high and medium discharge periods than the low discharge period. The basin‐wide estimate was underestimated by up to 36% if discharge was ignored, and up to 37% for lower stream orders. Future research should therefore include seasonality in stream surface areas in upscaling procedures to better constrain basin‐wide fluxes. Given that agricultural activities are a major factor increasing riverine greenhouse gas fluxes in the study region, increased conversion of forests and agricultural intensification has the possibility of increasing the contribution of the African continent to global greenhouse gas sources.

Description: Deutscher Akademischer Austauschdienst http://dx.doi.org/10.13039/501100001655

Description: IHE Delft Institute for Water Education

Description: Federal Ministry of Education and Research http://dx.doi.org/10.13039/501100002347

Description: Helmholtz Association http://dx.doi.org/10.13039/501100009318

Description: TERENO Bavarian Alps/ Pre‐Alps Observatory

Description: How will the theories and practices of democracy fare in a climate changing world? Are conventional democratic institutions ultimately doomed or are they able to become more responsive to a changing climate? Is there a need to reimagine democracy and how might it be reimagined? This article reviews the different responses to these questions by distinguishing between three “political imaginaries” in which the relationship between climate change and democracy takes distinct forms. I start by showing how the concept of “political imaginaries” can facilitate the comparison of the different ways in which the relation between democracy and climate change is constructed, before reviewing three such imaginaries. The skeptical imaginary, found in the “eco‐authoritarianism” of the 1970s that is echoed by much sociopolitical analysis today, casts doubt on the possibilities of democratic mechanisms to respond adequately and swiftly to the problem of climate change. Those who resist such skepticism often defend democracy by arguing that institutions and processes of democracy can be made more “ecologically rational”—the rational imaginary of climate democracy involves improvements in political representation and participation. Finally, I present the alternative radical democratic imaginary, in which the crisis of climate change provides a moment for the rupture of existing sociopolitical structures and the formation of alternatives. The article concludes that although none of these imaginaries is able to capture the entirety of climate change politics around the world, the radical democratic imaginary is responsive to the inevitable and valuable plurality around the issue of climate change. This article is categorized under: Climate, Nature, and Ethics 〉 Ethics and Climate Change Policy and Governance 〉 Multilevel and Transnational Climate Change Governance

Description: Climate protests may mobilise new political subjects.

Description: In recent years, the issue of high groundwater levels has caught attention. Unfavorable consequences of high groundwater levels are especially damage to buildings, infrastructure, and the environment. Processes that lead to high groundwater levels are hydrological (heavy or extended rainfall and flood events), or anthropogenic (reduced groundwater extractions, interaction with sewer networks, hydraulic engineering measures, structural interventions in the water balance, and mining activities). Several different map products have been prepared for the information of inhabitants and for planning purposes, and also methods for damage and risk analysis related to high groundwater levels have been developed. Groundwater management measures and structural measures are available to reduce the risk related to high groundwater levels. An operational management system could be combined from existing components, but operational forecasting systems for high groundwater levels are—different to flood forecasting systems—not yet common practice. A better understanding of the processes and the development of integrated approaches for modeling, design, planning, forecasting, and warning, as well as improvement of interdisciplinary collaboration between different organizations, are recommendations for the future. This article is categorized under: Engineering Water 〉 Engineering Water Water and Life 〉 Conservation, Management, and Awareness Science of Water 〉 Hydrological Processes Science of Water 〉 Water Extremes

Description: Pumping water from a basement during the Neiße flood 2010 in Saxony. The clear water indicates that the basement flooding originates from groundwater (photo: Reinhard Schinke).

Description: The Ghohroud granitoids (GG), containing mafic microgranular enclaves (MMEs) are located in the central part of the Urumieh‐Dokhtar Magmatic Arc (UDMA) in central Iran. They are associated with the subduction‐related magmatism in the Alpine‐Himalayan orogenic belt. The GG are comprised of a variety of intermediate and felsic rocks, including tonalite, granodiorite, granite, diorite porphyry and monzodiorite. The MMEs are gabbroic diorite and tonalite in composition and characterized by a fine‐grained hypidiomorphic microgranular texture with occasional chilled margins. They show rounded, sharp or irregular contact with the host granitoids. The occurrences of quartz, K‐feldspar and corroded plagioclase indicate that MMEs are the products of mixing between mantle and crust‐derived magmas. New ages of zircon U–Pb dating reveal that the GG in the Kashan area emplaced at ca. 19–17 Ma (Burdigalian). All the samples of MMEs and granitoid host rocks in this study are metaluminous and calc‐alkaline with I‐type affinities. They are enriched in light rare earth elements (LREEs) and show slight negative Eu anomalies (Eu/Eu* = 0.36–0.95). These features in a combination with the relative depletion in Nb, Ta, Ti and P, indicate the granitoids and MMEs are closely associated with subduction‐related magmas at an active continental margin. The host rocks yield relatively homogeneous isotopic compositions of initial 87Sr/86Sr ratios ranging from 0.706036 to 0.707055, εNd(t) values varying from −2.25 to 0.8, and the Nd model ages (TDM) vary in a limited range of 0.70–0.96 Ga. The MMEs show similar initial 87Sr/86Sr ratios (0.706420–0.707366), εNd(t) values (−1.32 to −0.27), TDM (0.68–1.09 Ga) and Pb isotopic compositions with host granitoids, which imply they attained isotopic equilibration during magma mingling and mixing. In combination with the petrographic, chemical and isotopic results, we suggest that the origin of MMEs and their host rocks were related to the interaction between crust‐derived melts and mantle‐derived mafic magmas. The magma‐mixing event possibly occurred during the transition from subduction to collision in the UDMA along with the closure of the Neotethyan ocean.

Description: A comprehensive dataset from petrographic characteristics to geochemical compositions of the mafic microgranular enclaves and granitoid host rocks from the Urumieh–Dokhtar Magmatic Arc (Iran) was presented. The new data provide significant insight into the evolution of magmatism in this area, which was tightly related to the Neotethyan closure. image

Description: National Nature Science Foundation of China

Description: TMU Research Grant Council

Description: Arctic and alpine aquatic ecosystems are changing rapidly under recent global warming, threatening water resources by diminishing trophic status and changing biotic composition. Macrophytes play a key role in the ecology of freshwaters and we need to improve our understanding of long‐term macrophytes diversity and environmental change so far limited by the sporadic presence of macrofossils in sediments. In our study, we applied metabarcoding using the trnL P6 loop marker to retrieve macrophyte richness and composition from 179 surface‐sediment samples from arctic Siberian and alpine Chinese lakes and three representative lake cores. The surface‐sediment dataset suggests that macrophyte richness and composition are mostly affected by temperature and conductivity, with highest richness when mean July temperatures are higher than 12°C and conductivity ranges between 40 and 400 μS cm−1. Compositional turnover during the Late Pleistocene/Holocene is minor in Siberian cores and characterized by a less rich, but stable emergent macrophyte community. Richness decreases during the Last Glacial Maximum and rises during wetter and warmer climate in the Late‐glacial and Mid‐Holocene. In contrast, we detect a pronounced change from emergent to submerged taxa at 14 ka in the Tibetan alpine core, which can be explained by increasing temperature and conductivity due to glacial runoff and evaporation. Our study provides evidence for the suitability of the trnL marker to recover modern and past macrophyte diversity and its applicability for the response of macrophyte diversity to lake‐hydrochemical and climate variability predicting contrasting macrophyte changes in arctic and alpine lakes under intensified warming and human impact.

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

Description: National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809

Description: Second Tibetan Plateau Scientific Expedition and Research Program

Description: https://doi.pangaea.de/10.1594/PANGAEA.920866

Description: https://doi.org/10.5061/dryad.k6djh9w4r

Description: Urban green space is increasingly viewed as essential infrastructure to build resilience to climate change by retaining water in the city landscape and balancing ecohydrological partitioning into evapotranspiration for cooling and groundwater recharge. Quantifying how different vegetation types affect water partitioning is essential for future management, but paucity of data and the complex heterogeneity of urban areas make water balance estimates challenging. Here, we provide a preliminary assessment of water partitioning from different sized patches of trees and grass as well as from sealed surfaces. To do this, we used limited field observations together with an advanced, process‐based tracer‐aided ecohydrological model at a meso‐scale (5 km2) in central Berlin, Germany. Transpiration was the dominant green water flux accounting for over 50% of evapotranspiration in the modelled area. Green water fluxes were in general greater from trees compared with grass, but grass in large parks transpired more water compared with grass in small parks that were intensively used for recreation. Interception evaporation was larger for trees compared with grass, but soil water evaporation was greater for grass compared with trees. We also show that evapotranspiration from tree‐covered areas comprise almost 80% of the total evapotranspiration from the whole model domain while making up less than 30% of the surface cover. The results form an important stepping‐stone towards further upscaling over larger areas and highlights the importance of continuous high‐resolution hydrological measurements in the urban landscape, as well as the need for improvements to ecohydrological models to capture important urban processes.

Description: Berlin University Alliance / Einstein Stiftung Berlin, Climate and Water under Change

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

Description: Einstein Stiftung Berlin http://dx.doi.org/10.13039/501100006188

Description: Leverhulme Trust http://dx.doi.org/10.13039/501100000275

Description: Urban Climate Observatory (UCO) Berlin

Description: Iron flocculants play a major role in the remediation of water bodies, removing particulate pollutants such as microplastics through floc formation. Such flocs are prone to microbial iron reduction while lying on top of anoxic sediments, which possibly leads the release of bound microplastics. In this study, Shewanella oneidensis was employed to simulate the impact of microbial iron reduction on the release of polyethylene spheres from sunken flocs in 120 d batch experiments. Most of the flocs iron (oxyhydr)oxides were reduced (70–90%), but this did not affect their integrity. Only a negligible proportion (0.2–2.7%) of polyethylene spheres was released, while the majority remained bound inside the floc matrix. This study exemplifies that flocs are quite stable, even when experiencing microbial iron reduction under anoxic conditions. Thereby incorporation into such aggregates may display a potential mode of long‐term microplastics storage in freshwater sediments.

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

Description: https://doi.org/10.48758/ufz.11330

Description: Extreme wind storms can strongly influence short‐term variation in lake ecosystem functioning. Climate change is affecting storms by altering their frequency, duration, and intensity, which may have consequences for lake ecosystem resistance and resilience. However, catchment and lake processes are simultaneously affecting antecedent lake conditions which may shape the resistance and resilience landscape prior to storm exposure. To determine whether storm characteristics or antecedent lake conditions are more important for explaining variation in lake ecosystem resistance and resilience, we analyzed the effects of 25 extreme wind storms on various biological and physiochemical variables in a shallow lake. Using boosted regression trees to model observed variation in resistance and resilience, we found that antecedent lake conditions were more important (relative importance = 67%) than storm characteristics (relative importance = 33%) in explaining variation in lake ecosystem resistance and resilience. The most important antecedent lake conditions were turbidity, Schmidt stability, %O2 saturation, light conditions, and soluble reactive silica concentrations. We found that storm characteristics were all similar in their relative importance and results suggest that resistance and resilience decrease with increasing duration, mean precipitation, shear stress intensity, and time between storms. In addition, we found that antagonistic or opposing effects between the biological and physiochemical variables influence the overall resistance and resilience of the lake ecosystem under specific lake and storm conditions. The extent to which these results apply to the resistance and resilience of different lake ecosystems remains an important area for inquiry.

Description: EU‐ITN MANTEL

Description: Marie Sklodowska‐Curie

Description: https://aslopubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2Flno.11859&file=lno11859-sup-0001-Supinfo1.docx

Description: https://aslopubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2Flno.11859&file=lno11859-sup-0002-Supinfo2.docx

Description: The fluorophore [2‐(4‐pyridyl)‐5{[4‐dimethylaminoethyl‐aminocarbamoyl‐methoxy]phenyl}oxazole], in short PDMPO, is incorporated in newly polymerized silica in diatom frustules and thereby provides a tool to estimate Si uptake, study diatom cell cycles but also determine mortality‐independent abundance‐based species specific‐growth rates in cultures and natural assemblages. In this study, the theoretical framework and applicability of the PDMPO staining technique to estimate diatom species specific‐growth rates were investigated. Three common polar diatom species, Pseudo‐nitzschia subcurvata, Chaetoceros simplex, and Thalassiosira sp., chosen in order to cover a broad range of species specific frustule and life‐cycle characteristics, were incubated over 24 h in control (no PDMPO) and with 0.125 and 0.6 μM PDMPO addition, respectively. Results indicate that specific‐growth rates of the species tested were not affected in both treatments with PDMPO addition. The specific‐growth rate estimates based on the PDMPO staining patterns (μPDMPO) were comparable and more robust than growth rates estimated from the changes in cell concentrations (μcc). This technique also allowed to investigate and highlight the importance of the illumination cycle (light and dark phases) on cell division in diatoms.

Description: The pelagic ecosystem of the Arctic Ocean is threatened by severe changes such as the reduction in sea‐ice coverage and increased inflow of warmer Atlantic water. The latter is already altering the zooplankton community, highlighting the need for monitoring studies. It is therefore essential to accelerate the taxonomic identification to speed up sample analysis, and to expand the analysis to biomass and size assessments, providing data for modeling efforts. Our case study in Fram Strait illustrates that image‐based analyses with the ZooScan provide abundance data and taxonomic resolutions that are comparable to microscopic analyses and are suitable for zooplankton monitoring purposes in the Arctic. We also show that image analysis allows to differentiate developmental stages of the key species Calanus spp. and Metridia longa and, thus, to study their population dynamics. Our results emphasize that older preserved samples can be successfully reanalyzed with ZooScan. To explore the applicability of image parameters for calculating total mesozooplankton and Calanus spp. biomasses, we used (1) conversion factors (CFs) translating wet mass to dry mass (DM), and (2) length–mass (LM) relationships. For Calanus spp., the calculated biomass values yielded similar results as direct DM measurements. Total mesozooplankton biomass ranged between 1.6 and 15 (LM) or 2.4 and 21 (CF) g DM m², respectively, which corresponds to previous studies in Fram Strait. Ultimately, a normalized biomass size spectra analysis provides 1st insights into the mesozooplankton size structure at different depths, revealing steep slopes in the linear fit in communities influenced by Atlantic water inflow.

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

Description: Proficiency testing (PT) is one of the few ways for an analytical laboratory to assess data quality under routine operating conditions. Here we report the results of Round 1 of the G-Chron PT programme, which is sponsored by the International Association of Geoanalysts. G-Chron is the first PT scheme devoted to the U-Th-Pb dating of mineral phases, primarily zircon, in geological materials. In this first round of G-Chron a total of 72 geochronology laboratories received the test material “Rak-17”, which previously had been characterized by seven well-established isotope dilution TIMS laboratories. A total of 63 of the PT participating laboratories reported data by the 15 December 2019 deadline. Here we both report and assess the measurement results submitted to this round. Our analysis provides a means for participating laboratories to assess their individual performance in relation to the isotope ages assigned, the experimental fitness-for-purpose criteria proposed by the scheme’s organisers and the results of similar laboratories participating in this round.

Description: The Earth is rotating around its rotation axis in an irregular manner. The Earth rotation axis and its orientation in space vary with respect to the reference system (both the terrestrial and the celestial) due to the wide range of processes that contribute to the rotation excitation. Therefore, the study of the Earth rotation can provide essential information concerning the Earth system. Spaceborne geodetic sensors can determine Earth orientation parameters (EOP), which fully describe Earth’s behaviour in space. The EOP are needed for several fields and applications such as fundamental astronomical and geodetic reference systems, precise satellite orbit determination, space navigation, and disaster prevention.\\ Over the past three decades, climate change has caused undesirable alterations in living organisms, human activities, and socio-economic aspects. Climate change is fluctuating and alters weather patterns such as precipitation patterns and sea and ocean levels. It also threatens the biodiversity of ecosystems, food security, and human health, and exacerbates natural disasters. The intensity and frequency of natural hazards are increasing with erratic distribution due to changes in the climate. Also, the level of vulnerability and zonation of risk are changed. Analysis of natural hazards, such as atmospheric and hydrological events, can help improve crisis management. Therefore, satellite observation data and simulated data derived from different atmospheric models are needed in order to model different types of hazards and risks, which can help early warning and prediction systems. Even though continuous sensor measurements and archive data (historical data/climate) are used for weather forecasting in developed countries, deadly flooding happened close to Stuttgart in southern Germany in May 2016, which might be avoided by a precise weather warning system. Therefore, real-time space geodetic technique data estimation is necessary to use as input data in weather prediction models. For the analysis of space geodetic techniques in (near) real-time, predictions of the EOP are required. EOP are made available by the International Earth Rotation and Reference Systems Service (IERS) Rapid Service Prediction Centre at USNO, Washington D.C., with a delay of hours to days. Accordingly, in the past, several methods were developed and applied for the EOP prediction. However, the accuracy of EOP prediction is still unsatisfactory, even for prediction of just a few days in the future.\\ To improve the EOP prediction accuracy, this study investigates the consistency between Earth rotation’s theories and observations. Moreover, the potentials of different geophysical phenomena are examined to better understand the interaction of different processes that affect the Earth rotation excitation with the time. Most of the Earth’s rotation theories and solutions are based on the location of the Earth’s principal axes of inertia (PAI). That location is defined by the second-degree Stokes coefficients of the geopotential, which are accurately observed by the Gravity Recovery and Climate Experiment (GRACE) and satellite laser ranging (SLR). In this study, the evolution of the Earth’s axes of inertia is analyzed for the first time. The presented results are remarkable, as the inertia axes do not move around a mean position fixed to a given terrestrial reference frame in the study period, but drift away from their initial location in a non-negligible manner.\\ Moreover, this study proposes a novel hybrid approach to predict EOP. There is a well-introduced stochastic method called copula-based analysis, and I combined it with singular spectrum analysis (SSA) for EOP prediction. I analyzed the potential of copula-based methods for predicting Earth rotation parameters that are derived from the combination of different satellite geodetic sensors and from other geophysical parameters like effective angular momentums. The copula is a statistical method that exploits linear and non-linear relationships between two or more variables by fitting a theoretical copula function into an empirical bivariate or multivariate distribution function. I introduced a hybrid prediction method that can be applied to other geophysical parameters is introduced in this thesis.\\ In this study, the interconnection between the celestial pole motion (CPM) and geomagnetic field (GMF) is investigated to improve the current CPM prediction methods. During the last decade, several investigations have been conducted in order to discuss a possible interconnection of polar motion and geomagnetic jerks, which are rapid changes in GMF secular variations. However, less attention has been paid to the impact of the GMF changes on the CPM, e.g., the interrelation of the geomagnetic jerks, geomagnetic dipole moment, geomagnetic field elements, and CPM variations. In this study, I use the CPM time series obtained from very long baseline interferometry (VLBI) observations and the latest GMF data to explore the correlation between CPM and the GMF. Our preliminary results revealed some impressive common features in the CPM and GMF variations, which show the potential to improve our understanding of the GMF’s contribution to the Earth’s rotation. All in all, the results mathematically illustrate the coherency between the GMF parameters and CPM, which helps improve EOP products.

Description: Die Erde dreht sich um ihre Rotationsachse auf unregelmäßige Art und Weise. Die Erdrotationsachse und ihre Orientierung im Raum variieren in Bezug auf das Referenzsystem (sowohl im terrestrischen wie auch im zälestischen System) aufgrund des breiten Spektrums von Prozessen, die zur Rotationsanregung beitragen. Daher kann die Untersuchung der Erdrotation wesentliche Informationen über das Erdsystem liefern. Weltraumgestützte geodätische Sensoren liefern Informationen über erdgebundene Orientierungsparameter (EOP), die das Verhalten der Erde im Weltraum vollständig beschreiben. EOP werden für verschiedene Bereiche und Anwendungen, wie beispielsweise für grundlegende astronomische und geodätische Referenzsysteme, benötigt. Des Weiteren sind sie auch für die präzise Bestimmung von Satellitenorbits und die weltraumgestützten Navigation, bis hin zu Anwendungen im Katastrophenschutz von Bedeutung.\\ In den letzten drei Jahrzehnten zeigen sich bereits die negativen Auswirkungen des Klimawandels auf Biosphäre, menschliche Aktivitäten und sozioökonomische Aspekte. Der Klimawandel unterliegt Fluktuationen und verändert die Wettermuster, wie z.B. die Niederschlagsverteilung, sowie Meeres- und Ozeanspiegel. Er bedroht aber auch die biologische Vielfalt der Ökosysteme, die Ernährungssicherheit, die menschliche Gesundheit und verschlimmert Naturkatastrophen. Die Intensität und Häufigkeit von Naturgefahren werden zunehmen, hierbei ist ihre Verteilung aufgrund von Klimaveränderungen allerdings unregelmäßig; auch der Grad von Schadensanfälligkeiten und die Einteilung von Risikozonen werden sich zukünftig ändern.\\ Die Analyse von Naturgefahren, wie atmosphärische und hydrologische Ereignisse, kann zur Verbesserung des Krisenmanagements beitragen. Daher werden Satellitenbeobachtungen und simulierte Daten, die von verschiedenen atmosphärischen Modellen abgeleitet werden, für die Gefahr- und Risikomodellierung benötigt; dies kann Frühwarn- und Vorhersagesysteme unterstützen. Obwohl kontinuierliche Sensormessungen und Archivdaten (historische Daten/Klimadaten) für die Wettervorhersage in entwickelten Ländern zur Verfügung stehen, kamen es im Mai 2016 in der Nähe von Stuttgart in Süddeutschland bei einer katastrophalen Überschwemmung zu Verlusten von Menschenleben, die möglicherweise durch ein präzises Wetterwarnsystem vermeidbar gewesen wären. \\ Eine Echtzeitschätzung der geodätischen Weltraumtechnik wäre notwendig, um sie als Eingangsdaten in Wettervorhersagemodellen zu verwenden. Für die Analyse von raumgeodätischen Techniken in (nahezu) Echtzeit sind Vorhersagen der EOP unerlässlich. EOP werden durch das Rapid Service Prediction Centre des International Earth Rotation and Reference Systems Service (IERS) am USNO, Washington D.C., mit einer Verzögerung von Stunden bis Tagen zur Verfügung gestellt. Demzufolge wurden in der Vergangenheit mehrere Methoden für die EOP-Vorhersage entwickelt und angewendet. Die Genauigkeit dieser EOP-Vorhersagen ist jedoch nach wie vor - selbst für einen Vorhersagezeitraum von nur wenigen Tagen - unbefriedigend.\\ Um die Genauigkeit der EOP-Vorhersage zu verbessern, beschäftigt sich die vorliegende Studie mit der Untersuchung von der Vereinbarkeit von Erdrotationstheorien mit Beobachtungen. Darüber hinaus wird das Potenzial verschiedener geophysikalischer Phänomene analysiert, um die Wechselwirkungen verschiedener Prozesse, die die zeitabhängige Anregung der Erdrotation beeinflussen, besser zu verstehen.\\ Die meisten Theorien und Lösungen zur Erdrotation basieren auf der Lage der Hauptträgheitsachsen der Erde (PAI). Diese Position wird durch die Stokes-Koeffizienten zweiten Grades des Geopotentials, das mit Hilfe der Satellitenmission Gravity Recovery and Climate Experiment (GRACE) und der Satelliten-Laser-Entfernungsmessung (SLR) genau beobachtet wird, definiert. In dieser Studie wird zum ersten Mal die Entwicklung der Trägheitsachsen der Erde analysiert. Bemerkenswert an den vorgestellten Ergebnissen ist, daß sich die Trägheitsachsen während der Untersuchungsperiode nicht um eine mittlere Position, die in einem bestimmten terrestrischen Bezugsrahmen festgelegt ist, bewegen, sondern sich in nicht zu vernachlässigender Weise von ihrem ursprünglichen Position entfernen.\\ Darüber hinaus schlägt diese Studie einen neuartigen hybriden Ansatz zur EOP-Vorhersage vor. Es gibt eine gut eingeführte stochastische Methode, die “kopula-basierte Analyse”, die wir mit der “Singulär-Spektrum-Analyse” (SSA) für die EOP-Vorhersage kombiniert haben . Wir analysierten das Potenzial kopula-basierter Methoden zur Vorhersage von Erdrotationsparametern, die aus der Kombination verschiedener geodätischer Satellitensensoren und aus anderen geophysikalischen Parametern, wie z.B effektiven Drehimpulsen, abgeleitet werden. Die Kopula ist eine statistische Methode, die lineare und nicht-lineare Beziehungen zwischen zwei oder mehreren Variablen nutzt, indem eine theoretische Kopula-Funktion an eine empirische, bivariate oder multivariate Verteilungsfunktion angepasst wird. Wir haben eine hybride Vorhersagemethode entwickelt, die auch auf andere geophysikalische Parameter angewendet werden kann.\\ In dieser Studie wird der Zusammenhang zwischen der Bewegung des Himmelspols (CPM) und dem geomagnetischen Feld (GMF) untersucht, um die derzeitigen CPM-Vorhersagemethoden zu verbessern. Während des letzten Jahrzehnts wurden mehrere Untersuchungen durchgeführt, um eine mögliche Verbindung zwischen polaren Bewegungen und geomagnetischen Ausbrüten - hierbei handelt es sich um rasche Veränderungen der säkularen Variationen des GMF - zu erörtern. Weniger Aufmerksamkeit wurde jedoch den Auswirkungen der GMF-Änderungen auf die CPM, z.B. der Wechselbeziehung der geomagnetischen Ausbrüte, des geomagnetischen Dipolmoments, der geomagnetischen Feldelemente und der CPM-Variationen, gewidmet. In dieser Studie verwenden wir CPM-Zeitreihen, die aus Beobachtungen der Very Long Baseline Interferometry (VLBI) gewonnen wurden und aktuelle GMF-Daten, um die Korrelation zwischen CPM und GMF zu untersuchen. Unsere vorläufigen Ergebnisse zeigen einige auffallente Gemeinsamkeiten in den CPM- und GMF-Variationen, die das Potenzial besitzen, unser Verständnis des GMF-Beitrags zur Erdrotation zu verbessern. Alles in allem veranschaulichen die Ergebnisse mathematisch die Kohärenz zwischen den GMF-Parametern und der CPM und weisen damit perspektivisch den Weg für eine Verbesserung der EOP-Produkte.

Description: This study presents an enhancement to the Global Navigation Satellite Systems (GNSS) by integrating low Earth orbiters (LEOs) to a joint precise orbit determination (POD) processing. The Global Position System (GPS) operated by the United States is studied as a representative of all GNSS. The LEOs equipped with GNSS receivers supplement the receivers of the ground stations, especially for regions with a limited number of employed stations, which can be caused by various reasons. Due to the altitude and high velocity of LEOs, they not only contribute with additional observations, but also with a rapidly-changing observation geometry. Moreover, space-based observations have additional advantages over ground-based observations, e.g., signals are received without the impact of the troposphere. LEOs not only act as kinematic stations for GNSS satellites, but also bring additional orbit dynamics to the integrated system. The constraints caused by these orbit dynamics have an important impact on the determination of the orbits of the GNSS satellites and other parameters beyond that. In this thesis, the following topics are presented: 1) Background information and the basic principles related to the POD of GNSS satellites and LEOs, 2) the separated POD of GNSS satellites and LEOs, 3) the integrated POD, 4) the determination of the antenna phase center offsets (PCOs) of the GPS satellites and other geodetic parameters in the integrated POD. The orbit modeling and processing configuration used in this study for GNSS satellites and LEOs are verified to be compatible with state-of-the-art studies by the separated POD. The orbits of the GNSS satellites and LEOs reach an accuracy of a few centimeters and are comparable with the state-of-art studies. A more efficient outlier detection method has been developed to improve the position determined by using pseudo-range observations. In the study about the enhancement of the GPS orbits by integrating LEOs, a 26-station ground network in a global and sparse distribution is supplemented by different subsets of seven LEOs including GRACE-A/B, OSTM/Jason-2, Jason-3 and, Swarm-A/B/C. A 34% improvement of the GPS orbit in 1D-mean RMS (from 37.5 mm to 23.9 mm) is achieved by including the seven LEOs. Both the number of space-based observations and the LEOs' orbital geometry affect the GPS orbits where the orbital geometry is shown to be more important. The estimated GPS PCOs are also improved by including LEOs. For the x- and y-components of the GPS PCOs, the formal error is reduced significantly due to the additional observations and expanded nadir angle coverage brought by the LEOs during the periods of large solar-elevation angle. The z-component of the GPS PCOs (z-PCO) are strongly correlated with the scale of the terrestrial reference frame. By introducing the orbit dynamics of the seven LEOs to the processing without applying a no-net-scale constraint, the correlation coefficients between the GPS z-PCOs and the scale are reduced from 0.85 to 0.30. Consequently, the GPS z-PCOs can be estimated independently from the a-priori scale and a purely GNSS-based scale can be determined as well. A system-specific -25.5 cm offset of the GPS z-PCOs relative to the values offered by the International GNSS Service (IGS) is computed based on the seven-LEO-integrated solution. Another approach based on Galileo also solves this problem. The GPS satellites, multi-GNSS stations, and Galileo satellites with ground calibrated PCOs are processed jointly to calibrate the GPS z-PCOs and simultaneously determine a Galileo-based scale simultaneously. Based on the comparison and cross-check, a good agreement is shown between the LEO-based and Galileo-based methods. There is a slight improvement in the geocenter when including three Swarm satellites to the processing with about 80 ground stations over a half year. Based on the analysis in theory and the results derived from real data, an obvious enhancement to various aspects of GNSS by the integrated processing with LEOs is shown. More LEOs equipped with GNSS receivers and carefully calibrated PCOs are expected for further missions or even the next generation of GNSS.

Description: In dieser Arbeit wird eine Verbesserung der globalen Satellitennavigationssysteme (GNSS) durch die Einbindung von Satelliten in niedrigen Erdumlaufbahnen (LEOs) in eine gemeinsame präzise Bahnbestimmung (POD) vorgestellt. Das von den Vereinigten Staaten betriebene Global Positioning System (GPS) wird stellvertretend für alle GNSS untersucht. Die mit GNSS-Empfängern ausgestatteten LEOs ergänzen die Empfänger der Bodenstationen, vor allem in Regionen, in denen aus verschiedenen Gründen nur wenige Stationen verfügbar sind. Aufgrund der Orbithöhe und schnellen Bewegung der LEOs tragen diese nicht nur mit zusätzlichen Beobachtungen bei, sondern auch mit einer sich schnell verändernden Beobachtungsgeometrie. Darüber hinaus haben weltraumgestützte Beobachtungen zusätzliche Vorteile gegenüber bodengestützten Beobachtungen, z. B. werden Signale ohne den Einfluss der Troposphäre empfangen. LEOs stellen nicht nur kinematische Stationen für die GNSS-Satelliten dar, sondern bringen auch eine zusätzliche Bahndynamik in das integrierte System ein. Die durch diese Bahndynamik gegebenen Beschränkungen sind sowohl für die Bahnbestimmung der GNSS Satelliten als auch für weitere Parameter äußerst relevant. In dieser Arbeit werden die folgenden Themen behandelt: 1) Hintergrundinformationen und Grundprinzipien der POD von GNSS-Satelliten und LEOs, 2) eine separate POD von GNSS-Satelliten und LEOs, 3) eine integrierte POD, 4) die Schätzung der Antennen-Phasenzentrumsversätze (PCOs) der GPS-Satelliten und anderer geodätischer Parameter in der integrierten POD. Die separaten PODs bestätigen, dass die in dieser Studie verwendete Bahnmodellierungs- und Prozessierungskonfiguration der GNSS-Satelliten und LEOs mit dem aktuellen Stand der Forschung kompatibel ist. Die Bahnen der GNSS-Satelliten und LEOs erreichen eine Genauigkeit von wenigen Zentimetern. Es wurde eine effizientere Methode zur Erkennung von Ausreißern entwickelt, um die mit Hilfe von Pseudo-Range-Beobachtungen ermittelte Position zu verbessern. Ein Bodennetz mit 26 global dünn verteilten Stationen wird verwendet, um die Verbesserung der GPS-Bahnen durch die Integration von verschiedenen Teilgruppen der sieben LEOs GRACE-A/B, OSTM/Jason-2, Jason-3 und Swarm-A/B/C zu untersuchen. Bei der Einbeziehung aller sieben LEOs ergibt sich eine Verbesserung des 1D RMS Mittelwertes der GPS-Orbits von 34 % (von 37,5 mm auf 23,9 mm). Sowohl die Anzahl der weltraumgestützten Beobachtungen als auch die Geometrie der Bahnen der LEOs beeinflussen die GPS-Bahnen, wobei die Orbitgeometrie sich als der wichtigere Faktor erweist. Die geschätzten GPS PCOs werden durch die Einbeziehung von LEOs ebenfalls verbessert. Der formale Fehler der x- und y-Komponenten der GPS PCOs wird durch die zusätzlichen Beobachtungen und die größere Abdeckung des Nadirwinkels, den die LEOs während Perioden eines großen Sonnenstandswinkels mit sich bringen, erheblich reduziert. Die z-Komponente der GPS PCOs (z-PCO) ist mit dem Maßstabsfaktor des terrestrischen Referenzrahmens stark korreliert. Durch die Berücksichtigung der Bahndynamik der sieben LEOs in der Prozessierung werden ohne Fixierung des Maßstabes (d.h. ohne eine No-Net-Scale Bedingung) die Korrelationskoeffizienten zwischen den GPS z-PCOs und dem Maßstabsfaktor von 0,85 auf 0,30 reduziert. Folglich können zum einen die GPS z-PCOs unabhängig von einem externen Maßstab geschätzt werden und zum anderen kann ein rein GNSS-basierter Maßstabsfaktor bestimmt werden. Mit der integrierten Lösung mit sieben LEOs ergibt sich ein systemspezifischer Versatz der GPS z-PCOs von -25,5 cm relativ zu den vom International GNSS Service (IGS) veröffentlichten Werten. Ein anderer Ansatz basierend auf Galileo löst dieses Problem ebenfalls. Die GPS Satelliten, Multi-GNSS Bodenstationen und Galileo Satelliten mit bodenkalibrierten PCOs werden gemeinsam prozessiert, um die GPS z-PCOs zu kalibrieren und gleichzeitig einen Galileo-basierten Maßstabsfaktor zu bestimmen. Ein Vergleich zur Überprüfung zeigt eine hohe Übereinstimmung der LEO- und Galileo-basierten Methoden. Die Einbeziehung von drei Swarm Satelliten in eine Prozessierung mit etwa 80 Bodenstationen über ein halbes Jahr hinweg zeigt eine leichte Verbesserung des Geozentrums. Auf der Grundlage der theoretischen Analyse und der aus realen Daten abgeleiteten Ergebnisse zeigt sich eine deutliche Verbesserung verschiedener Aspekte der GNSS durch die Integration von LEOs. Es ist zu erwarten, dass mehr LEOs, ausgestattet mit GNSS-Empfängern und sorgfältig kalibrierten PCOs, für künftige Missionen oder sogar die nächste GNSS Generation eingesetzt werden.

Description: This report summarises the webinars organised in the REFLECT project between 2021 and 2022, in the framework of the WP6 Dissemination and exploitation, Task 6.2 – Ensure transferability and exploitation of project results. The Task 6.2 planned to inform the stakeholders identified in the matrix developed under Task 6.1 about the project activities and main outcomes. For this purpose, periodic webinars have been organised between 2021 and 2022 presenting these results and information.

Description: This report presents the stakeholder workshops organised in the REFLECT project, in the framework of the WP6 Dissemination and exploitation, Task 6.2 – Ensure transferability and exploitation of project results. The Task 6.2 planned to inform the stakeholders identified in the matrix developed under Task 6.1 about the project activities and main outcomes. For this purpose, two physical stakeholder workshops were organised during the project. The first workshop, at the start of the project, was dedicated to a first communication of the project’s objectives and expected outcomes. It also had the aim to receive feedback from geothermal operators on their most significant operational problems related to geothermal fluid properties. This first workshop was, therefore, limited to the Advisory Board members in order to build on their specific experience. The second stakeholder workshop presented the project’s results most relevant to geothermal operators or service companies/consultants. The objective of the second stakeholder workshop was to share projects results with a broad group of stakeholders. Therefore, it was widely promoted and the registration was open to all and free of charge. Both workshops received positive feedback from stakeholders and project partners.

Description: This deliverable summarises the methodology and results of the data collection for the European Fluid Atlas by the REFLECT project partners.

Description: The main objective of the work package 2 of the REFLECT project is to characterise relevant fluid properties and their reactions for saline fluids (type C). One of the specific goals was to collect fluid samples from several saline fluids from geothermal sites across Europe, determine their properties, and thus contribute to the Fluid Atlas (WP3). Additionally, the REFLECT team will compare those field data with data from lab experiments performed at near natural conditions. Samples of type C fluids were taken from several sites in Germany, Austria, Belgium and the Netherlands. The samples were analysed for major and minor ions, dissolved gases and isotopes.

Description: Global growth of industry and population leads to increasing demand of industrial and consumer goods. This necessitates an increase in mining activities and resource extraction. Resulting mine waste, and tailings serve as a repository for unused overburden and for the accumulation of processed waste-products. It is typical for so-called secondary iron minerals (SIMs) to be formed during the weathering of these materials under different pH-value conditions. Acid mine drainage (AMD) can result from rainwater infiltration and chemical processes within the deposited mass. Therefore, mine tailings must be spatially separated from their surroundings and monitored. The emergence of remote sensing methods provides new opportunities to survey large areas. In this work a remote sensing approach was used to discriminate SIMs from surrounding material and minerals and subsequently classify different SIMs on the surface. This allows to reconstruct (/comprehend the former) the acidic environments that prevailed during the formation of these minerals and gives indication of the occurrence of AMD. Various SIMs have pH-values ranging from strongly acidic (〈1.5, i.e., Schwertmannite and Copiapite) to neutral (〉7, i.e., Hematite). Classifying these SIMs, leads to the identification of contaminated areas. This method was developed based on a laboratory dataset with different minerals and vegetation samples. The datasets were originally acquired with hyperspectral HySpex cameras in the laboratory and were resampled to WorldView-3 (WV3) and Sentinel-2 (S2) band characteristics for analysis. A combination of different filter methods made pixel-based separation of SIMs possible. The results were subsequently classified using a RF-model to distinguish between different SIMs. In this training dataset, the RF model achieved an overall accuracy of 94.44% for the WV3 and S2 datasets (the area-adjusted overall accuracy was 93.45% and 93.62%, respectively). Subsequently, a second laboratory dataset with field samples was analysed using the same technique and the classification results were compared with XRD analyses of the samples. Satellite images from WV3 and S2 sensors were then analysed using this methodology. The results for the study area of volcanogenic massive sulphide deposits in the Republic of Cyprus, namely Skouriotissa and Apliki, were then compared. The results for the Skouriotissa mine region showed a potential area of 17.22 to 45.58 ha of strongly acidic environment (by classification of Jarosite, pH~2.4) and 8.86 to 26 ha of moderately acidic environment/ contamination (by classification of Goethite/Limonite, pH~5) based on the WV3 satellite image. 27.32 to 87.04 ha and 6.12 to 38.24 ha for the S2 image, respectively.

Description: Das Wachstum von Industrie und Bevölkerungszahl weltweit sowie technologische Fortschritte und Entwicklungen führen zu einer steigenden Nachfrage von Industrie- und Konsumgütern. Als Folge entstehen eine erhöhte Rohstoffnachfrage und ein Ausbau der Ressourcengewinnung sowie des Bergbaus. Abfallprodukte des Bergbaus und nicht genutztes Material (Abraum) werden meist in oder um den Abbaustandort aufgeschüttet. Diese sind natürlichen Degradationsprozessen ausgesetzt, bei denen saure Abwässer entstehen können. Dies geschieht durch die Verwitterung des Pyrit Minerals infolge der Infiltration von Regenwasser durch das Material. In unterschiedlichen pH-Wertumgebungen bilden sich unterschiedliche Minerale aus. Typisch sind die sogenannten sekundären Eisenminerale (SIMs – secondary iron minerals). Ein Auftreten dieser kann daher zu einer pH-Wert Abschätzung genutzt werden und mögliche saure Grubenwässer aufzeigen. Fernerkundungsmethoden bieten die Möglichkeit große Areale oberflächlich zu erfassen und abzubilden, was zu einer weitreichenden Überwachung genutzt werden kann. In dieser Arbeit wurde eine Methode auf Grundlage von multispektralen Fernerkundungsdaten (Satellitenbilder von WorldView-3 und Sentinel-2) entwickelt, welche sekundäre Eisenminerale identifiziert und klassifiziert. Die Identifikation wurde durch den Einsatz von Masken erreicht. So fand eine Unterscheidung zwischen Pixeln statt, die und die keine typische spektrale Signale von SIMs aufweisen. Die Klassifikation wurde mit Hilfe eines RF-Modells durchgeführt. Dieses wurde anhand synthetischer Labordatensätze entwickelt und validiert. Im Trainingsdatensatz erreichte das RF-Modell eine Gesamtgenauigkeit von 94,44 % für die WorldView-3 und Sentinel-2 Datensätze. Es wurden drei Klassen mit verschiedenen pH-Wert-Identifikationen unterschieden: Hämatit (pH〉7), Goethit/ Limonit (pH~5) und Jarosit (pH~2.4). Die Methodik wurde anschließend auf Satellitenbilder aus der Republik Zypern angewendet. Dabei standen die Minengebiete Skouriotissa und Apliki im Fokus, welche zu den vulkanogenen Massivsulfid-Lagerstätten (VMS-type) zählen. Die Ergebnisse für das Skouriotissa-Minengebiet ergaben auf der Grundlage des WV3-Satellitenbildes eine potenzielle Fläche von 17,22 bis 45,58 ha in stark saurem Milieu (Jarosit) und 8,86 bis 26 ha in mäßig saurem Milieu (Goethit/ Limonit) bzw. 27,32 bis 87,04 ha und 6,12 bis 38,24 ha für das Sentinel-2 Satellitenbild.

Description: The evaluation of the effect of organic compounds and microorganisms in formation and precipitation of colloids using artificial brines was performed by TNO using selected organic compounds based on the analysis of sampled fluids corresponding to the information gathered on the sites by GFZ. The same was done with biofilms prepared with microorganisms (Thermaerobacter sp., Penicilium citrinum) isolated from geothermal stations by UNINE. All carboxylic acids tested had an inhibiting effect on the precipitation of calcium carbonate. The biofilm components seem to develop intense interaction with the ions, nuclei and/or crystals formed during the executed experiments. In the presence of biofilms, the transformation of the intrinsically formed vaterite morphology to equilibrium calcite morphologies is delayed or hindered and scaling was inhibited.

Description: The Global Geodetic Reference Frame (GGRF) plays a fundamental role in geodesy and related Positioning, Navigation, and Timing applications, and allows to quantify the Earth’s change in space and time. The ITRF and ICRF are the two most important components to realize GGRF, while the determination of these two reference frames relies on the combination of several space geodetic techniques, mainly, VLBI, SLR, GNSS, and DORIS. The combination is currently done on either the parameter level, or the normal equation level. However, the combination on the observation level, or the so-called integrated processing of multi-technique on the observation level, provides the results of best consistency, robustness, and accuracy. This thesis focuses on the investigation of the integrated processing of GNSS and VLBI on the observation level. The benefits of integrated processing are demonstrated in terms of TRF, CRF, and EOP, while the impact of global ties (EOP), tropospheric ties, and local ties are underlined. Several issues in integrated processing are addressed, including the systematic bias in ties (for instance, LOD and tropospheric ties), the relative weighting. An automatic reweighting strategy based on the normalized residuals is developed, which can properly handle the uncertainty of the ties without losing too much constraint. A software with state-of-the-art modules is the prerequisite to perform integrated processing. Based on the GNSS data processing software: Positioning And Navigation Data Analyst (PANDA), the VLBI and SLR modules are implemented in the common least-squares estimator. Therefore, the best consistency can be guaranteed. The software capability is demonstrated with the single-technique solutions. The station coordinate precision is at millimeter level for both GNSS and VLBI, while the EOP estimates are comparable to other Analysis Centers and the IERS products. It is also demonstrated that the SLR station coordinate precision is improved by 20% to 30% with additional GLONASS and GRACE satellites to contributing to the LAGEOS and ETALON constellation. Focusing on the tropospheric ties in GNSS and VLBI integrated processing, its contribution is demonstrated for the first time comprehensively. Applying tropospheric ties improves the VLBI station coordinate precision by 12% on the horizontal components and up to 30% on the vertical component. The network scale repeatability is reduced by up to 33%. The EOP estimates are also improved significantly, for instance, 10% to 30% for polar motion, and up to 10% for other components. Furthermore, applying the gradient ties in the VLBI intensive sessions reduces the systematic bias in UT1-UTC estimates. The consistent TRF, CRF, and EOP are achieved in the integrated VLBI and GNSS solution. Applying the global ties, tropospheric ties, and local ties stables the reference frame. The ERP estimates in the integrated solution are dominated by the GNSS technique, and the VLBI technique introduces additional 10% improvement on the y-pole component in terms of the day-boundary-discontinuity. The UT1-UTC and celestial pole offsets are also slightly improved in the integrated solution. It is also demonstrated that applying the LTs inappropriately distorts the network and introduces systematic biases to the ERP estimates, addressing the necessity of updating the local surveys. Moreover, the coordinates of AGN are also enhanced by up to 20% in the integrated solutions, especially the southern ones. This study reveals the importance of integrated processing of multi-technique on the observation level, as the best consistency can be achieved, and the applied ties improve the solutions significantly. It is strongly recommended that for the future realization of celestial and terrestrial reference frames, the concept of integrated processing on the observation level should be implemented, and all the possible ties should be applied, including the global ties (EOP), local ties, space ties, and tropospheric ties. Such kind of integrated solution of all the four techniques can provide robust estimates of the reference frames and EOP, with the advantage of each technique exploited to its full extend.

Description: Der Globale Geodätische Referenzrahmen (Global Geodetic Reference Frame, GGRF) spielt eine fundamentale Rolle in der Geodäsie und den damit verbundenen Positionierungs-, Navigations- und Zeitmessungsanwendungen (Positioning, Navigation, and Timing, PNT) und ermöglicht die Quantifizierung der Veränderung der Erde in Raum und Zeit. Der ITRF und der ICRF sind die beiden wichtigsten Komponenten zur Realisierung des GGRF, wobei die Bestimmung dieser beiden Referenzrahmen auf der Kombination verschiedener raumgeodätischer Techniken beruht, hauptsächlich VLBI, SLR, GNSS und DORIS. Die Kombination wird derzeit entweder auf der Parameterebene oder auf der Normalgleichungsebene durchgeführt. Die Kombination auf der Beobachtungsebene oder die sogenannte integrierte Daten-Verarbeitung von Multi-Techniken auf der Beobachtungsebene, bietet jedoch eine Lösung mit der besten Konsistenz, Robustheit und Genauigkeit. Diese Arbeit konzentriert sich auf die Untersuchung der integrierten Daten-Verarbeitung von GNSS und VLBI auf der Beobachtungsebene. Die Vorteile der integrierten Lösung werden in Bezug auf TRF, CRF, und EOP aufgezeigt, während die Auswirkungen von „Global Ties (EOP), Tropospheric Ties, and Local Ties“ hervorgehoben werden. Einige Punkte der integrierten Verarbeitung werden in dieser Arbeit untersucht, einschließlich der systematischen Abweichungen von „Ties“ (z.B. LOD und Tropospheric Ties), der relativen Gewichtung usw. Anhand der normalisierten Residuen wird eine automatische Umgewichtungsstrategie entwickelt, mit der die Unsicherheit der „Ties“ angemessen behandelt werden kann, ohne dass zu viel Einschränkung dabei verloren geht. Eine Software mit modernsten Modulen ist die Voraussetzung für die integrierte Daten Verarbeitung. Basierend auf der GNSS-Datenverarbeitungssoftware Paket: Positioning And Navigation Data Analyst (PANDA) werden die Module VLBI und SLR in demselben Least-Squares-Estimator wie GNSS implementiert, damit kann man die beste Konsistenz in der Datenverarbeitung erreichen. In dieser Arbeit wird die Leistungsfähigkeit der Software mit den Ein-Technik-Lösungen demonstriert. Die Genauigkeit der Stationskoordinaten liegt sowohl für GNSS als auch für VLBI im Millimeterbereich, und die geschätzten EOP-Parameter sind auch mit der anderer Analysezentren und den IERS-Produkten vergleichbar. Es wird auch gezeigt, dass die Koordinatengenauigkeit der SLR-Station um 20-30% verbessert wird, wenn zusätzliche GLONASS- und GRACE-Satelliten zur LAGEOS und ETALON-Konstellation beitragen. Mit dem Schwerpunkt auf den „Tropospheric Ties“ in der integrierten GNSS- und VLBI- Daten Verarbeitung wird ihr Beitrag zum ersten Mal umfassend dargestellt. Die Anwendung der „Tropospheric Ties“ verbessert die Genauigkeit der VLBI-Koordinaten um 12% bei der horizontalen Komponente und bis zu 30% bei der vertikalen Komponente. Die Genauigkeit im Netzwerkmaßstab wird um bis zu 33% verbessert. Auch die EOP-Bestimmungen werden deutlich verbessert, z.B. um 10-30% bei polaren Bewegungen und bis zu 10% bei anderen Komponenten. Darüber hinaus reduziert die Einführung der „Gradient Ties“ in der VLBI-Intensivsession die systematische Abweichung in den dUT1-Bestimmungen. Die konsistente TRF, CRF, und EOP werden bei der integrierten VLBI- und GNSS-Lösung erreicht. Die Anwendung der „Global Ties, Tropospheric Ties and Local Ties“ stabilisiert die Bestimmungen des Referenzrahmens. Die ERP-Bestimmungen in der integrierten Lösung werden von der GNSS-Technik dominiert, und die VLBI-Technik bringt eine zusätzliche Verbesserung um 10% auf die Tagesgrenzen-Diskontinuität (day-boundary-discontinuity, DBD) für die y-Pol-Komponente. Die dUT1- und CPO werden in der integrierten Lösung ebenfalls leicht verbessert. Es wird auch gezeigt, dass eine ungeeignete Anwendung der LTs das Netzwerk verzerrt und systematische Abweichungen in die ERP-Bestimmungen einführt, wodurch die Notwendigkeit einer Aktualisierung der lokalen Tie Messungen deutlich wird. Darüber hinaus werden die Koordinaten der AGN in den integrierten Lösungen um bis zu 20% verbessert, insbesondere im Süden. Diese Arbeit zeigt die Bedeutung der integrierten Daten Verarbeitung von Multi-Technik auf der Beobachtungsebene, da die beste Konsistenz erreicht werden kann und die angewandten „Ties“ die Lösungen erheblich verbessern. Es wird nachdrücklich empfohlen, für die zukünftige Realisierung von himmelsfesten und erdfesten Referenzrahmen das Konzept der integrierten Verarbeitung auf Beobachtungsebene durchzuführen und alle möglichen „Ties“ anzuwenden, einschließlich der „Global Ties (EOP), Local Ties, Space Ties, and Tropospheric Ties“. Eine solche integrierte Lösung aller vier Techniken kann die robusten Bestimmungen der Referenzrahmen und der EOP liefern, wobei die Vorteile jeder Technik voll ausgeschöpft werden.

Description: South Wales is characterised by a rich variety of geologic formations and rocks of different ages and periods, and a large asymmetric syncline, as perhaps its most significant structural geological feature, extending from east to west over a length of approximately 96 km and 30 km from north to south, respectively. This oval-shaped syncline is part of the Variscan orogenic thrust and fold belt in Central Europe and covers some 2,700 km2, with coal-bearing rocks from the Upper Carboniferous (Westphalian Stage) deposited in the central syncline and older rocks outcropping in a peripheral belt around it. The coal-bearing sequence begins with Namurian grits and shales, overlain by the more productive Lower, Middle and Upper Coal Measures. A 3D structural geological model has been implemented for the central part of the South Wales Syncline and its bedrock geology. The oldest rocks in the model domain date back to the Pridoli Series from the uppermost Silurian, the youngest to the Westphalian Stage of the Upper Carboniferous. For model implementation, mainly open access data from the British Geological Survey (BGS) has been used. The final 3D structural geological model covers the entire Central South Wales Syncline and is 32.8 km wide and 36.6 km long. In total, the 3D model includes 21 fault zones and the elevation depth of ten surfaces: (1) Top Upper Coal Measures Formation; (2) Top Middle Coal Measures Formation; (3) Top Lower Coal Measures Formation; (4) Top Millstone Grit Group; (5) Top Dinantian Rocks; (6) Top Upper Devonian Rocks; (7) Top Lower Devonian Rocks (sandstone dominated); (8) Top Lower Devonian Rocks (mudstone dominated); (9) Top Pridoli Rocks; (10) Top Ludlow Rocks (in parts).

Description: This Technical Report presents data from a solaroptical spectral investigation in the area of the Rammelsberg non-ferrous metal mine in the Harz Mountains near the city of Goslar. The investigation refers to the local communion stone quarry (“Kommunionssteinbruch”) above the former mining area. As this is a nature conservation zone, all measurements were carried out in-situ without any physical sampling action. The field measurements were carried out in June 2019 in cooperation with Bergbau Goslar GmbH and the German Research Centre for Geosciences (GFZ). The data were collected within the research project ReMon (Remote Monitoring of Tailings Using Satellites and Drones, https://www.gfzpotsdam. de/en/section/remote-sensing-and-geoinformatics/projects/remon/) which aims at developing a prototypical monitoring system for mine tailings by using different sensors scaling from satellite- to drone-based. The data were analysed in the unpublished B.Sc. thesis of Constantin Hildebrand (Hildebrand, 2019). Sixteen different surface materials were determined and examined on-site. Point and imaging hyperspectral data were acquired (with the spectroradiometer PSR+ 3500 operating in the range of 350 - 2500 nm and with the Cubert FireflEYEUHD-185 hyperspectral camera with a range of 450 - 950 nm, respectively), both data sets are presented as spectral libraries. Chemical analyses of the samples were performed by using Laser-Induced Breakdown Spectroscopy (LIBS). LIBS data were collected using a handheld LIBS analyzer, the SciAps Z-300. In this report the different in-situ measurements are presented for each of the sixteen samples. Detailed information about the analysed material, the area of spectral sampling and geochemical analyses are explained in this report and can also be found in the additional Excel® sheet provided with the data.

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Description: This document is a collection of the REFLECT factsheets produced for promoting the project results.

Description: This deliverable summarizes the activities related to the development of predictive models to simulate the impact of fluid flow hydrodynamics and chemical composition uncertainties on the production behavior of geothermal assets. Specifically, in this report, the mineral precipitation behavior of the geothermal fluid was studied as both uncertainties in the fluid composition and the interaction between the fluid flow hydrodynamics and mineral precipitation can impact the deposition of the scaling. A workflow was developed to couple a multiphase flow solver to thermodynamics libraries and models which are used to simulate the precipitation amount and kinetics of different geothermal minerals. This coupled workflow will enable a better estimation of the location and amount of precipitated minerals in different location of a geothermal system. A detailed roughness model was developed to simulate the impact of mineral deposition to the fluid flow. In addition, an uncertainty quantification workflow was combined with the modelling framework to estimate the uncertainty bounds of the scaling and precipitation resulted from uncertainties in the fluid composition characterization and operational settings. The modelling and uncertainty quantification workflow was demonstrated on a barite precipitation case study in a heat exchanger. Initially, the impact of geo-chemical uncertainties (in fluid composition) on the mineral precipitation was assessed. Afterwards, the coupled fluid flow and precipitation model with the developed roughness model was tested. Finally, the coupled uncertainty quantification workflow with the coupled model was simulated to assess the impact of fluid composition uncertainties on mineral deposition. As an outcome of the simulation, the impact of uncertainties in the mineral deposition on reduction in the production rate and heat transfer (within the heat exchanger) was calculated. The developed framework is flexible and generic which can be applied to various production and operational challenges in geothermal assets. In the future, the workflow can be used to optimize the design and operation of geothermal assets considering various sources of uncertainties which is not only fluid composition but also operational conditions (link to D4.5 REFLECT), robust modelling of other geo-chemical and flow assurance challenges in geothermal sites or even developing geo-chemical risk maps for different sites within EU (link to WP3 REFLECT).

Description: This brochure is designed for scientists and engineers of upcoming drilling projects and explains the key steps and important challenges in planning and executing continental scientific drilling.