DGL Annual Meeting


Vierzig Jahre  Einfluss auf Süßwassersysteme

Forty years of human impact on freshwater systems

39th DGL Annual Meeting 2024


TUD Dresden University of Technology,

16–20 September 2024

Photos: Felix Grunicke


General topics (A)

A 1 Diversity and ecology of aquatic communities

A 2 Extreme events and global change

A 3 Hydrodynamics and ecology

A 4 Microbial ecology

A 5 Multiple stressors

A 6 Aquatic food webs

A 7 Matter fluxes in aquatic communities

A 8 Urban and heavily modified water bodies

A 9 Long-term monitoring

Special Sessions (S)

S1 New perspectives in stream restoration – a focus on structure-function relationships   ●  Fink, Patrick, Helmholtz Centre for Environmental Research – UFZ, patrick.fink(at)ufz.de  ●  Anlanger, Christine, RPTU Kaiserslautern-Landau  ●  Brauns, Mario, Helmholtz Centre for Environmental Research – UFZ  ●  Lorenz, Armin, University of Duisburg-Essen  ●  Pasqualini, Julia, Helmholtz Centre for Environmental Research – UFZ  ●  Schlenker, Alexandra, Helmholtz Centre for Environmental Research – UFZ Session language: English Running water ecosystems have been modified for human use for centuries, repurposing them as water source for consumption and irrigation, transportation, sewage disposal, or as a source of hydraulic energy. These different types of usage often severely impacted the organisms within lotic ecosystems and their overall health and ecological status. In recent decades, increasing efforts have been devoted to restore streams and rivers with the ultimate aim of recovering their hydromorphology and, thus biodiversity. The success of those restoration measures is often quantified, if at all, on very limited temporal and spatial scales only. Furthermore, previous studies of restoration success were limited to either structural aspects (such as channel hydromorphology, biodiversity or aspects of hygiene), whereas ecosystem functions, such as leaf litter breakdown or oxygen metabolism, received little attention. In this session, we want to bring together structural and functional aspects of restoration ecology and invite talks that quantified restoration success in aquatic or floodplain ecosystems. S2 Hidden successes – Evaluating complementary success factors of river restoration   ●  Kaiser, Nina N., Hochschule Trier, Umwelt-Campus Birkenfeld, n.kaiser(at)umwelt-campus.de  ●  Palt, Martin, Hochschule Trier, Umwelt-Campus Birkenfeld, m.palt(at)umwelt-campus.de  ●  Remmers, Wolfram, Hochschule Trier, Umwelt-Campus Birkenfeld, w.remmers(at)umwelt-campus.de  ●  Borgwardt, Florian, Universität für Bodenkultur Wien, florian.borgwardt(at)boku.ac.at  ●  Birk, Sebastian, Universität Duisburg-Essen, sebastian.birk(at)uni-due.de  ●  Stoll, Stefan, Hochschule Trier, Umwelt-Campus Birkenfeld, s.stoll(at)umwelt-campus.de Session language: German and English (slides: english) In recent decades, restoration of water bodies has increasingly become the focus of management plans and regulations in order to reverse the degradation of aquatic habitats caused by human activity. In this context, the Water Framework Directive (WFD) has established the ecological status as a key assessment criterion. However, despite the now considerable number of restoration projects, success at the level of ecological status and the associated biological quality components is often unsatisfactory. Yet restoration and nature-based solutions also have complementary and further-reaching effects that are not adequately captured by WFD-compliant assessment, which means that successes at these levels remain invisible. These successes can be described using a variety of approaches: They include functional metrics of the aquatic biocoenosis as well as, for example, interaction with the floodplain and the surrounding area or socio-ecological effects, which point to the great potential of water bodies to provide ecosystem services. The wider context (e.g. land use, recolonisation potential) also plays a key role in determining which restoration measures can be assessed as successful in terms of their impact potential. A holistic view of restoration projects and their successes enables a differentiated assessment, which is particularly important when communicating with the public in order to promote acceptance of restoration. Given the twin crises of biodiversity loss and climate change, further efforts such as the proposed Nature Restoration Law will be necessary in the future to make habitats resilient and ecological. We therefore invite contributions to this session that present a broad spectrum of studies, approaches and innovative methods that deal with the more general success factors in the context of freshwater restoration. Based on the contributions and discussions, the session will provide an overview of existing integrated approaches and their significance for implementation practice in planning and evaluation. This will provide a basis for transferring the findings to future restoration projects and contextualising the success of projects that have already been implemented. S3 Temporary streams in Europe - new challenges for ecologists, ecotoxicologists and hydrologists   ●  Hering, Daniel, Universität Duisburg Essen, Fakultät für Biologie, Aquatische Ökologie, daniel.hering(at)uni-due.de  ●  Jungmann, Dirk, Technische Universität Dresden, Institut für Hydrobiologie, dirk.jungmann(at)tu-dresden.de  ●  Lorenz, Armin, Universität Duisburg Essen, Fakultät für Biologie, Aquatische Ökologie, armin.lorenz(at)uni-due.de Session language: English Climate change is expected to have significant impacts on the occurrence of temporary watercourses, particularly due to altered precipitation patterns and prolonged dry periods. Warming and increased evaporation resulting from climate change will further stress watercourses by depleting their water reserves more rapidly, thereby increasing the frequency of temporary water flows. However, the specific effects will vary from region to region depending on geographical location and local climatic conditions. In Germany, criteria for assessing the ecological condition of temporary watercourses are still in development but can draw valuable insights from assessments in other arid areas. In addition to ecological considerations such as changes in habitat structure, the focus is on water quality, particularly the effects of chemical pollution and hydrological parameters. It is crucial to emphasize that the ecological assessment of temporary watercourses is a multidisciplinary approach encompassing both biological and physical aspects. An integrated approach enables a comprehensive evaluation of the ecological condition, playing a vital role in the protection and sustainable use of these delicate ecosystems. Therefore, we aim to consolidate scientific findings on these issues in a session and, in a subsequent workshop, articulate solutions and challenges concretely. S4 Large rivers under multiple pressures: multidisciplinary insights and perspectives into river management from the Oder and other rivers   ●  Münzner, Karla, Leibniz Institute of Freshwater Ecology and Inland Fisheries, karla.muenzner(at)igb-berlin.de  ●  Fischer, Helmut, Bundesanstalt für Gewässerkunde, helmut.fischer(at)bafg.de  ●  Masigol, Hossein, Leibniz Institute of Freshwater Ecology and Inland Fisheries, hossein.masigol(at)igb-berlin.de Session language: German and English Large rivers are highly impacted by climate change and human activity, such as impoundments, decrease in flow, and pollution. This can promote eutrophication and, for example, create conditions ideal for the formation of harmful algal blooms, like in the Oder River in August 2022 where a toxic Prymnesium parvum bloom formed after an increase in salinity. The result was a mass mortality of fish and other aquatic organisms along a 300 km stretch of the river. How the Oder River is recovering and how P. parvum blooms can be avoided in the future is now under investigation. However, events like the Oder catastrophe are a threat to rivers in all of Germany and Europe; they require cooperation between managers and researchers of different disciplines to protect rivers and their ecosystem services from the pressures they face. We welcome all contributions dealing with the ecology or management of the Oder River, or on other rivers where multiple pressures have led to complex impacts, such as eutrophication and harmful algal blooms. We especially encourage studies that take an interdisciplinary approach to address these topics. S5 Modelling and managing water quantity and quality in international river systems in the face of climate change   ●  Oprei, Anna, Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB), anna.oprei(at)igb-berlin.de  ●  Venohr, Markus, Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB), markus.venohr(at)igb-berlin.de Session language: German and English Climate change alters hydrological regimes and challenges the integrity of our water resources. For example, extended low flow periods may lead to temporal and regional increase of pollutant concentrations, such as nutrients, salt, heavy metals or other substances, potentially enhancing eutrophication or impacting aquatic habitats. Since the implementation of the EU Water Framework Directive (WFD), publicly available high-resolution data as well as knowledge on aquatic processes and nutrient transformations has steadily grown. Although the WFD status assessment has been harmonized between countries, the management is often limited to national and administrative borders. As monitoring provides indispensable information on the status of groundwater and surface waters, runoff and nutrient emission modelling in combination with related field studies help to identify vulnerable freshwater systems and set a basis for sustainable water resource management. The modelling of emission pathways and nutrient transformation requires profound knowledge of the entire hydrological catchment. Therefore, such models are forced by a high number of input data, e.g. precipitation, evapotranspiration, hydrogeology, groundwater, soil type, land use, tile drainage, erosion and population density including the collection and treatment of waste water. High-resolution input data is often not available in the same quality in hydrologically connected neighboring countries. Using alternative international input data or combining different national data sets may cause inconsistencies in the models and reduce the quality and robustness of the results. Moreover, global change adds a pressing need to base management plans on transnational, basin-wide input data, modelling and assessments. Against this background, we propose to discuss how nutrient emission modelling can be brought to a higher level by e.g. combining national data or model assessments, using open-source data or providing open modelling platforms to bridge the gap between theoretical model development and practical application. This session aims to join scientists working in experimental limnology as well as nutrient emission modelling to advance the prediction and management of water quality at the catchment scale against the background of a changing climate. S6 Estuaries – unique environment under multiple stressors   ●  Fiskal, Annika, Bundesanstalt für Gewässerkunde (BfG), fiskal(at)bafg.de  ●  Große, Fabian, Bundesanstalt für Gewässerkunde (BfG), grosse(at)bafg.de  ●  Dähnke, Kirstin, Helmholtz-Zentrum Hereon, kirstin.daehnke(at)hereon.de  ●  Sanders, Tina, Helmholtz-Zentrum Hereon, tina.sanders(at)hereon.de Session language: English Estuaries – the transition zones between inland and coastal waters, freshwater and seawater – constitute highly complex, unique environments continuously affected and modified by a multitude of natural processes and human interventions. Tidally affected estuaries exhibit significant changes in water levels and salinity over the tidal cycle, while at the same time experiencing long-term morphological changes due to the tidal influence on the dynamics of sediment and suspended matter. These morphological changes also control the formation and (re )distribution of habitat types, such as intertidal flats or saltmarshes, within the estuaries. In addition, river discharge and biological productivity in the river upstream significantly impact estuarine ecosystems, e.g., by controlling the amount of organic matter imported into the estuary, which in turn plays a key role in estuarine oxygen dynamics. For centuries, estuaries have been affected by human activities, such as shipping and fisheries, and today, they are among the most frequented waterways in the world providing access to large seaports and inland waterways. For this reason, many estuaries have been developed and are continuously maintained in order to allow access to estuarine ports for increasingly larger vessels. At the same time, population growth and urbanization have increased the spatial demand for housing, industries and agriculture at the expense of a reduction in natural estuarine flood plains and tidal habitats. This development directly affects estuarine dynamics and ecosystem functioning. In addition, indirect effects, such as eutrophication of inland waters and climate change, impose further stress on estuarine ecosystems as they may deteriorate estuarine oxygen conditions or increase flood risk due to sea level rise. To recognize the complexity of estuarine systems and their importance in a strongly anthropogenically affected environment, this special session welcomes contributions that address topics in the aquatic and terrestrial estuarine spheres – ranging from morphology to biogeochemistry and ecology – and using different methodological approaches including, but not limited to, in situ or laboratory measurements as well as remote sensing or modeling. S7 Computational Limnology: How data-driven and process-based modeling, and field research inspire each other   ●  Feldbauer, Johannes, TU Dresden, Institut für Hydrobiologie, johannes.feldbauer(at)tu-dresden.de  ●  Frassl, Marieke, Bundesanstalt für Gewässerkunde, frassl(at)bafg.de  ●  Schwefel, Robert, IGB Berlin, Abt. 1: Ökohydrologie und Biogeochemie, robert.schwefel(at)igb-berlin.de  ●  Petzoldt, Thomas, TU Dresden, Institut für Hydrobiologie, thomas.petzoldt(at)tu-dresden.de Session language: English Computational limnology, the application of computational methods for the study of freshwater ecosystems, has become increasingly important in advancing our understanding of aquatic environments. The integration of data-driven and process-based modeling has synergistic effects, with each approach informing and enhancing the other. Both types of models rely on high-quality field data for knowledge acquisition, calibration, and validation. By identifying key variables and relationships from observational data, data-driven models provide insights into the complex dynamics of aquatic systems, helping researchers focus their fieldwork on critical areas or processes. Combining data-driven and process-based models allows for a more comprehensive understanding of freshwater ecosystems. Data-driven models can capture complex relationships and patterns, while process-based models provide mechanistic insights into the underlying ecological and hydrological processes. The synergy between data-driven and process-based modeling not only inspires and informs laboratory and field research, but also ensures that models remain grounded in the realities of natural systems. This interdisciplinary approach enhances our ability to manage and conserve freshwater resources effectively. The session aims to bring together researchers and topics from various fields. We welcome contributions on the analysis of long-term and high-frequency data sets, from data science projects, mechanistic modelers or studies that combined data-driven and process-based modelling. S8 Novel approaches to assess or detect biodiversity, contaminants, pathogens or antibiotic resistance in freshwater systems   ●  Vernick, Sefi, Agricultural Research Organization (Israel), sefi(at)volcani.agri.gov.il  ●  de la Cruz Barron, Magali, TU Dresden Institute of Hydrobiology, magali.de_la_cruz_barron(at)tu-dresden.de  ●  Kneis, David, TU Dresden Institute of Hydrobiology, david.kneis(at)tu-dresden.de  ●  Berendonk Thomas TU Dresden Institute of Hydrobiology thomas.berendonk(at)tu-dresden.de  ●  Klümper Uli TU Dresden Institute of Hydrobiology uli.kluemper(at)tu-dresden.de Session language: English In recent years, the detection and monitoring of biodiversity, contaminants, pathogens and antibiotic resistance have advanced significantly due to the integration of innovative technologies and methodologies. E.g. eDNA can detect species presence with high sensitivity and specificity, even for elusive or rare species, without the need for direct observation or capture. This non-invasive approach is especially valuable in aquatic environments, where traditional survey methods can be challenging and disruptive. Biosensors represent another innovative approach in biodiversity and pathogen detection. These devices combine biological components with a physicochemical detector to identify and quantify specific species. Biosensors are being developed to be highly sensitive, capable of detecting species at very low concentrations, and providing results in real-time. This makes them particularly useful in ecological settings. The detection of pathogens and antibiotic resistance has become increasingly crucial in the context of global public health. Innovative methods have been developed in recent years to enhance the accuracy, speed, and efficiency of these detections, which are essential for effective disease control and prevention. Finally, e.g. metagenomics or Qq-PCR methods, the study of genetic material recovered directly from environmental samples, has emerged as a powerful tool in detecting of microbial diversity, pathogens and antibiotic resistance in community and environmental settings. This approach provides a comprehensive overview of the microbial communities and their resistance genes, aiding in the surveillance and control of antibiotic resistance on a larger scale. In conclusion, the integration of these new methods marks a significant advancement in the field of freshwater ecology. By leveraging these researchers can more effectively screen biodiversity, surveil infectious diseases and tackle the growing challenge of antibiotic resistance. Consequently, we invite abstracts that utilize novel methods to assess biodiversity, pollutants, pathogens or antimicrobial resistance in freshwater systems. S9 Sustainable boating on lakes and rivers in Germany   ●  Peeters, Frank, Limnologisches Institut der Universität Konstanz, Frank.Peeters(at)Uni-Konstanz.de  ●  Köhler, Ralf, Landesamt für Umwelt Brandenburg, Referat W26: Gewässerentwicklung & Moorschutz, RalfH.Koehler(at)LfU.Brandenburg.de Session language: German Passenger ship traffic and recreational boating influence the ecological conditions in inland waters. Political initiatives of the German government and of individual federal states, as well as the interests of the tourism sector, have led to a noticeable increase in boating and associated pressures which already have substantial ecological impacts on lakes and rivers. In this session, basic concepts, research findings, and perspectives for the management and sustainable development of passenger transport and recreational boating will be collated and discussed. The focus is on the following fields: 1) Impacts of recreational boating and passenger ships on the aquatic environment; 2) Social and economic drivers for leisure boating; 3) Effects of boating on common objectives (e.g. EU WFD, biodiversity, FFH/Natura 2000, sustainability) and ecosystem services (ESS); 4) Mechanisms by which ecological pressures act on the ecological status of water bodies; 5) Options for limiting and reducing ecological impacts via development of sustainable management practices. We look forward to contributions from research and practitioners that address topics such as: 1) Impacts of boating on the aquatic community including fish and waterfowl; 2) Dispersal of neobiota through boating; 3) Impacts of waves generated by boats (e.g. bank erosion, fish); 4) Effects of boating infrastructure on valuable riparian zones (docks, harbors, etc.); 5) Ecological assessment/certification of boats, harbors and marinas; 6) Emissions of recreational boating (noise, exhaust gases, antifouling residues) and potentials for climate-neutral recreational boating; 7) User demands and development trends of the boat fleet and legal regulations (EU, federal government, federal states); 8) Management instruments and mitigation concepts. A summarizing discussion will take place at the end of the presentation block. Within the framework of this special session, the results of the project SuBoLakes (Sustainable Boating on Lakes in Germany, www.subolakes.de), which is funded by the German Federal Environmental Foundation (DBU) and will conclude in autumn 2024, will also be presented. S10 Floodplain ecology and the challenges of floodplain restoration   ●  Januschke, Kathrin, Universität Duisburg-Essen, kathrin.januschke(at)uni-due.de  ●  Scholz, Mathias, Helmholtz-Zentrum für Umweltforschung – UFZ, Department Naturschutzforschung, Leipzig, mathias.scholz(at)ufz.de  ●  Stammel, Barbara, Aueninstitut Neuburg-Ingolstadt, Katholische Universität Eichstätt-Ingolstadt, Barbara.Stammel(at)ku.de Session language: German Floodplains are the interface between aquatic and terrestrial habitats. They encompass numerous habitats that can be subject to strong seasonal, temporal and spatial change. Their categorisation is often unclear in science as well as in administration and management. Floodplains have therefore been neglected for decades, but have recently become the focus of greater scientific and management attention due to the upcoming challenges and diverse processes. In the course of the implementation of various guidelines and programmes and in connection with problems caused by climate change and extreme events (floods, droughts), the restoration of floodplains is increasingly coming to the fore in research and practice. This always raises the question of the success of measures in terms of improvements to structures and biodiversity. The session is intended to provide an insight into the different approaches to floodplain research and serve as a forum for an exchange between research and practice. The focus can be on morphological, hydrological and biological studies. Concrete case studies from restoration practice and monitoring success are expressly encouraged. S11 Freshwater mussels in Europe - Biologie, causes of endangerment and protective measures   ●  Grunicke, Felix, Institut für Hydrobiologie - TU Dresden, Felix.Grunicke(at)tu-dresden.de  ●  Daill, Daniel, blattfisch e.U. - technisches Büro für Gewässerökologie, daill(at)blattfisch.at Session language: German Freshwater mussels play a crucial role in limnic ecosystems by providing essential ecosystem services such as water filtration. Despite their importance, their populations are rapidly declining due to various threats, making them one of the most endangered freshwater organisms in Europe. Consequently, several research and conservation projects have been initiated in recent years to protect these animals. This session discusses the causes of endangerment and the necessary measures to protect freshwater mussel species. Contributions may also include new findings on the biology of individual species or groups. 

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