Karsten Rinke, Helmholtz Centre for Environmental Research – UFZ, Germany
karsten.rinke@ufz.de
Karl-Erich Lindenschmidt, University of Saskatchewan, SK, Canada
David Hamilton, Australian Rivers Institute, Griffith University, QLD, Australia

Many studies on climate change impacts predict signifcant changes for lakes and reservoirs with respect to physical and thermal structure, biogeochemical processing and ecosystem dynamics. Therefore, we are facing a growing demand (and pressure) to develop adaptation strategies. Reservoirs offer flexible operational options and ongoing changes in climate and catchment structure require adaptive management in order to fulfil the multiple purposes they are needed for. Even more, the services from reservoirs will most likely be more important in a warmer world and the expectations on their service-provisioning will rise. This leads to a situation where, on the one hand, ecosystem services of reservoirs are increasingly demanded and exploited but, on the other hand, the safe operating space for the ecological integrity of reservoirs and their upstream/downstream river networks will shrink. This session is intended to explore the expected risks, potential adaptation strategies as well as new approaches to monitoring, forecasting, and adaptive management.

Marco Cantonati, MUSE – Museo delle Scienze, Italy
marco.cantonati@muse.it
Kalina Manoylov, Georgia College, GA, USA

The monitoring and assessment of inland water quality based on benthic algae has become an important element of the methodological toolkit adopted by water authorities and in limnological research. The topic is particularly timely now that such environmental assessments are sparking growing interest worldwide and discussions and revisions of methods and procedures have been initiated. The integration of metagenomic methods into the established approaches is a particularly important development. We invite contributions to the session on all aspects of inland water assessments and monitoring based on benthic algae, continuing a long tradition of international symposia on the use of algae for monitoring rivers and comparable habitats. Thus, the session will provide an opportunity to review and discuss algae-based monitoring in different countries around the globe, as well as improvements to methods and techniques, their use in the implementation of legislation and regulations, and the discussion of novel approaches. We consider assembling a set of selected solicited or unsolicited papers presented at the session for publication in a special issue of an international journal, as has been the case in previous symposia organized on the topic.

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Xiufeng Zhang, Jinan University, China
wetlandxfz@163.com
Lars Rudstam, Cornell University, NY, USA

The goal of many biomanipulations is to reduce the abundance of planktivorous fish, either by addition of piscivorous fish or by manually removing or reducing the biomass of undesired fish. The method was originally intended to reduce grazing pressure on zooplankton, thereby increasing grazing pressure on phytoplankton by zooplankton, especially Daphnia, to increase water clarity and promote the growth of aquatic macrophytes. Biomanipulation has become a commonly used technique for improving water quality of lakes and reservoirs after external nutrient load reduction. From a management point of view, biomanipulation is likely to be most successful in the long term in shallow eutrophic lakes. With decades of successful applications as a method for lake restoration, its popularity is increasing in the Northern Hemisphere. However, the effectiveness is questionable in tropical and subtropical regions because Daphnia are less abundant and planktivorous fish may be omnivores and can produce eggs all year round making them harder to control. In addition, large phytoplankton in some eutrophic conditions are difficult to handle by the zooplankton, including Daphnia. Furthermore, in the scenario of global climate warming, biological invasion and the enhancing human activities, the percentage of omnivorous fish increases, which may lead to reduced control of zooplankton on phytoplankton. So, the success of biomanipulation may be challenged also in the temperate zone. In this special session we wish to promote cross-continent comparisons of grazing manipulation-based biotechnology for restoration of eutrophic waters. We encourage contributions discussing results from field studies, experiments, models, and theoretical analyses.

Natacha Tofield-Pasche, EPFL, Switzerland
natacha.tofield-pasche@epfl.ch
Bastiaan Ibelings, University of Geneva, Switzerland

Automated buoys are deployed in many lakes worldwide to collect and transmit an increasingly wide array of data acquired by sensors. Floating platforms have the added advantage of providing safe, dry and weather-protected working conditions, and allow installing laboratory instrumentation directly on the lake. Such automatic data collection has been shown to promote interdisciplinary lake studies with complementary measurements at high vertical and temporal resolution. More and more the integration of these in-situ lake data are being paired with and complemented by remote sensing. As an example of a floating laboratory providing access to different disciplines, we cite LéXPLORE (www.lexplore.info) a partnership of five academic institutions constructed a multipurpose platform for a broad range of scientific investigations on Lake Geneva (France, Switzerland). The scope of this session is to explore scientific investigations based on data collected at high-frequency with automatic buoys or floating platforms. One goal is to learn valuable lessons of established buoys and pioneering platforms, in order to promote such infrastructure elsewhere. Examples of research topics that have benefitted from the collection of diverse types of lake data, thus promoting a deeper understanding across disciplines in natural sciences, are lake gas exchange dynamics, carbon cycling, remote sensing, plankton dynamics, including blooms of toxic cyanobacteria or fish recruitment. Such infrastructure should be part of the next 100 years of sensing and safeguarding lake ecosystems.

Marco Toffolon, University of Trento, Italy
marco.toffolon@unitn.it
Robert Ladwig, University of Wisconsin-Madison, WI, USA
Samantha K. Oliver, U.S. Geological Survey, WI, USA
Sebastiano Piccolroaz, University of Trento, Italy
Tom Shatwell, Helmholtz-Centre for Environmental Research – UFZ, Germany

Smart monitoring technologies have seen a thriving development in the last decades. Earth observation is providing freely usable data at increasingly higher spatial and temporal resolution. Low-cost computational power has supported the use of brute force in the application of complex algorithms. Because of this, in general we are observing a shift of paradigm towards the development and application of data-driven models and hybrid mechanistic-statistical models, which require data for their training and validation. This is true for all fields of environmental science, including limnology, where the rising availability of high-quality data of different type and nature allows the application of models to an extent that was hardly imaginable before. Overall, the emerging field of theory-guided data science brings exciting novel research opportunities and applications, but the question remains: What is the perspective for the future? The session welcomes contributions dealing with the development and application of models of different type (e.g., machine-learning, statistical, deterministic, hybrid, etc.) using a variety of data (e.g., remote sensing, high-frequency data) in the field of limnology (e.g., lakes, ponds, lagoons, reservoirs, rivers, groundwater), with a particular focus on data-driven models and on the synergy between data science and modeling.

Alexander H. Frank, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany
alexander.frank@igb-berlin.de
Tobias Goldhammer, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany

Stable isotope signatures of the light elements CHNOS are well-established tracers for biologically mediated processes and functions in aquatic ecosystems and can be applied on different levels of ecological organization. Recently, the advent of more accessible analytical capabilities, as well as facilitation of sample preparation, have expanded the scope of target phases, molecules, and processes being monitored with increased coverage, enabling improved interpretation than previously possible. In this session, we showcase recent advances in the application of stable isotope signatures of CHNOS that have paved the way to unprecedented insights into key processes and their drivers in freshwater ecosystems. Examples include, but are not limited to photosynthesis and primary productivity, food webs and energy flow in trophic networks, organic matter turnover, and nutrient dynamics, novel biomarkers, and contamination problems such as microplastics.

Cécilia Barouillet, INRAE UMR CARRTEL, France
cecilia.barouillet@gmail.com
Laura Epp, University of Konstanz, Germany
Ebuka Nwosu, GFZ Helmholtz Center Postdam, Germany
Eric Capo, ICM-CSIC, Spain

The sedimentary DNA approach is rapidly evolving, opening new avenues to the field of aquatic ecology and paleoecology. In the context of freshwater habitats, molecular archives have allowed us to give a broad perspective about biological change, and new insights into ecosystem functioning, food-web dynamics and biodiversity of aquatic ecosystems over long time scales (i.e. centennial to millennial). Moreover, sedimentary DNA-based methods represent innovative ways towards the reconstruction of full trophic networks. In this session, we invite contributions from scientists applying the sedimentary DNA approach to study past changes in freshwater ecosystems. The goal of this session is to provide an overview of the research conducted in the field by using various sedimentary DNA techniques (e.g. qPCR, DNA metabarcoding, shotgun sequencing, hybridization capture) and diverse sites in order to demonstrate how the approach can help improve our understanding of the long-term dynamics of freshwater habitats in a complex multi-stressor world (e.g. eutrophication, invasive species, catchment alteration). We especially encourage presentations that provide insights into how information gained through sedimentary DNA research can help to improve freshwater management and conservation issues related to human-induced stressors in the context of climate change.

Abolfazl Irani Rahaghi, Eawag, Switzerland
abolfazl.irani@eawag.ch
Tiit Kutser, University of Tartu, Estonia

During the first one hundred years the limnological research has been predominantly based on in situ sampling in a limited number of waterbodies. Broadening of research problems (climate change, global carbon cycle, etc.) as well as technological advances in the last decades (automated buoy systems; airborne, surface and underwater drones, etc.) opened new possibilities for inland water research and monitoring. The launch of Sentinel satellites in the frame of the Copernicus Programme opened a new era in satellite remote sensing – moving from one-off scientific missions to long-term monitoring with confirmed funding for decades to come. Advancements in numerical modelling allow better understanding of the processes in inland waterbodies. On the other hand, they allow limnological research and monitoring to reach a new level where remote sensing, in situ data, and modelling are merged like in operational climate and weather services. This session aims at presenting the latest achievements in inland water remote sensing and integrated use of in situ data, remote sensing, and models. In particular, we invite contributions that demonstrate the development and employment of remote sensing for limnological research and monitoring as well as in investigating the underlying physical and biological processes by means of model simulations. This session will also provide researchers a chance to shape the future of Copernicus inland water services as the outcomes will be used in preparing a Roadmap for Future Copernicus Water Services that is to be developed in the future.

Jens Nejstgaard, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany
jens.nejstgaard@igb-berlin.de
Stella Berger, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Germany
Maria Stockenreiter, Ludwig-Maximilians-Universität Munich, Germany
Lisette de Senerpont Domis, Netherlands Institute of Ecology (NIOO-KNAW), The Netherlands
Meryem Beklioğlu, Middle East Technical University, Turkey
Paraskevi Pitta, Hellenic Centre for Marine Research, Greece
Robert Ptacnik, WasserCluster Lunz, Austria

Global climate change and other anthropogenic pressures have major impacts on our ecosystems, resulting in new challenges, requiring new scientific strategies. These strategies need to go beyond the classical scientific approaches. As such, they do not only need to yield understanding of ecosystem functioning and allow to predict future responses to increased anthropogenic forcing, but also need to actively suggest and test possible solutions to mitigate these pressures. Only then it is possible to take solution-oriented action for the prevention or restoration of negatively impacted ecosystems. Such new approaches include nature-based solutions and environmental engineering. Mesocosm studies allow for the required upscaling to gain complexity, closeness to nature and assessment of feasibility of solutions. We also propose that optimizing use of already collected data and collaboration across domains would boost the advancement of aquatic sciences. This session invites contributions ranging from curiosity driven basic experimental studies of aquatic ecosystems, modelling of such data, and presentations of novel approaches and experiments to actively mitigate negative effects on all types of aquatic systems, in celebration of the 100-yr anniversary of SIL. Since international networking between early career scientists is important to build tomorrows’ science, -with collaboration being the cornerstone of excellent mesocosm-based science-, we encourage students and early career scientists to present results and ideas to promote future collaboration. Such partnerships could be realized in open networks and funding possibilities such as the AQUACOSM-plus transnational Activities (www.aquacosm.eu). Please join us to look for truly new solutions, beyond our traditional borders.