Sessions

Aquatic viruses are abundant, and they are considered key players in structuring microbial communities and regulating phytoplankton. Little is, however, known about the diversity of viruses interacting with the different trophic levels within lake communities and to what extent community and biogeochemical cycling are affected by virus infections. The session aims to discuss methods to sample, detect and identify viruses, dynamics of host-virus systems and consequences for community/ecosystem dynamics and functioning.

Session chair: Ana del Arco, Lutz Becks

Vortragsspache: Englisch

Symbiotic relationships refer to the close association of two or more different species living physically together and comprise parasitic, commensalistic, mutualistic, competitive, and predator-prey interactions. Symbiotic interactions are common across all ecosystems and can determine ecosystem dynamics, functioning and persistence. The form of symbiosis is defined by the costs and benefits of the interaction for both partners, the relative duration of the association and the dependence of the partners on each other. All these factors in turn depend on the environment and (co)evolutionary history. Therefore, rather than referring to a single specific relationship, symbiosis is now recognized as a continuum of species interactions, where the form of the interaction may change with the environment. By affecting the organisms’ fitness, changes of symbiotic interactions potentially alter population dynamics and community composition. However, many symbiotic interactions, their costs and benefits and particularly potential shifts of such interactions in dependence of the biotic and abiotic environment are still poorly understood and hardly integrated into the broad theories of community structure and functioning. In this session we welcome observational, experimental and modelling studies that provide information and improve our understanding of symbiotic interactions in aquatic systems, their costs and benefits, and how feedbacks and controls operate. In particular, we welcome contributions addressing how the type of symbiotic interactions shift along environmental gradients and what consequences can be expected for ecosystem functioning, including food web structure and dynamics, biodiversity change, altered biogeochemical processes, and ecological shifts across temporal and spatial scales.

Session chairs: Sabine Flöder, Birte Matthiessen, Stefanie Moorthi

Vortragsspache: Englisch

Aquatic ecosystems are under severe pressure by several anthropogenic stressors affecting ecosystem state, development, and function. Trophic change, climate warming, changes in hydrology, but also the invasion by neobiota are consequences of human activities that have caused substantial and complex changes in aquatic ecosystems. The mechanisms leading to different patterns of ecosystem response, e.g. resilience, reversibility, regime shifts or others, are not yet well understood. In this session we invite contributions that investigate and analyze responses of aquatic ecosystems to changing conditions and aim at a better understanding of the meachisms behind ecosystem response patterns. All studies, whether they are based on the analysis of paleo- and field data or utilize experimental or numerical approaches, that support a process based understanding of the ecosystem responses are welcome.

This session will be organized by the RTG R3, Konstanz.

Vortragsspache: Englisch

Biofilms in fluvial ecosystems are spatially and temporally heterogeneous conforming microbial landscapes. These landscapes are modulated by physical habitat heterogeneity shaping both local biodiversity (structure and composition) and meta-community dynamics. The biogeochemical processes carried out by these microbial communities are affected by the physical habitat heterogeneity. The relationship between the structure and function of microbial landscapes is unclear as well as how it translates across scales determining biogeochemical processes at the reach scale, which is the scale at which nutrient cycling is determined and streams are managed. Our goal in this session is to explore the relationships between small scale biofilm properties and larger scale biodiversity and biogeochemistry. We invite contributions focusing on drivers of microbial community structure and function as well as upscaling approaches.

Session chairs: Anna Oprei, Ute Risse-Buhl

English & German

Legal requirements, guidelines and regulations demand the recording of aquatic communities in surface waters, e.g. for the nature conservation assessment of hydraulic engineering measures, the recording of biodiversity, the early detection of invasive species and the assessment of the ecological status of a water body, also within the framework of the EU Water Framework Directive.

For the biological quality elements fish, macrozoobenthos, phytobenthos and phytoplankton, the great potential of DNA-based recording of individual species and species communities has already been demonstrated in scientific studies and pilot projects. Through various national and international efforts, practical protocols and guidelines have been and are currently being developed and standardized for some organism groups and sample species to integrate DNA-based methods into regulatory monitoring and make them useful for ecological water assessment.

With the Special Session, we provide a forum for researchers and user groups to present projects and results on the current state of method development and standardization. In particular, the Special Session is intended to intensify the discussion on the still open research needs and existing limitations of the new methods with regard to their use in water management and nature conservation.

Session Chairs: Sascha Krenek, Julia Kleinteich, Florian Leese, Till-Hendrik Macher

English & German

The planktonic ecosystem is the largest on earth. Past limnological studies have substantially advanced our knowledge in understanding the wider role of plankton in ecology, evolution, and ecosystem functioning. This session aims to offer a forum for sharing recent results of studies in theoretical, experimental, and empirical aspects of plankton ecology to communicate the state-of-the-art in plankton research. The session calls for contributions of studies investigating e.g. biotic interactions and dynamics in plankton communities or the effects of environmental stressors, change, or variability on plankton organisms or communities. For instance, understanding the effects of environmental stressors on the physiology and ecology of plankton organisms is important for predicting the consequences of ongoing environmental changes on plankton communities and their dynamics. Studies investigating the effects of multiple environmental drivers or more complex food web interactions are especially welcome. Observational plankton studies are accepted, but preference will be given to hypothesis-driven studies that are conceptually well based on theory and report results of microcosm or mesocosm experiments, or ecological models. Contributions in English are preferred.

Session-Chair: Erik Sperfeld and Maria Stockenreiter

English

In the course of the implementation of various directives and laws, the number of watercourse and floodplain restoration projects is steadily increasing. Particularly for the flora and fauna of the banks and floodplains, some of them show good success, but the evaluation approaches often differ considerably.The session will give an insight into the different approaches in floodplain research and discuss the benefits and value for water research and evaluation. The focus may be on success monitoring of restoration efforts, addressing floodplain flora and fauna, basic morphological and hydrological conditions, or planning challenges. Amounts that integrate floodplain-relevant ecosystem functions and services in planning and evaluation are also welcome. Overall, this session is intended to provide a forum to discuss effects of restoration measures and their evaluation beyond the water's edge in the context of floodplain management.

Session chairs: Kathrin Januschke, Mathias Scholz, Barbara Stammel

English & German

The European Commission defined the Nature-based solutions (NBS) as living solutions inspired by, continuously supported by and using nature. They are designed to address various environmental challenges in a resource efficient and adaptable manner and to provide simultaneously economic, social and environmental benefits. NBS have been identified as crucial for ecosystem regeneration and improvement of human well-being, socio-ecological resilience, and multi-functional watershed management. At the level of the hydro-system, NBS are for example river restoration, wetland reactivation, floodplain management, riparian forest protection. NBS implementation face challenges as a missing proof of concept. Are NBS effective and sustainable? Which co-benefices are they delivering? We propose to bring together some of the emerging and leading researchers on NBS applied to the hydro-system. The session aims to increase our understanding of the NBS benefices, provide insight into NBS limits and formulate recommendations. Presentations will encompass for example remote sensing methods, ecosystem services assessment, estimation of ecological recovery, simulation under climate scenario, high resolution imaging techniques for measuring ecosystem vitality and biodiversity, so as tools to guide decision-making.

Session-Chair: Aude Zingraff-Hamed

English

Declining functional diversity reduces the capability of ecological systems to buffer against biotic and abiotic changes and to maintain ecosystem functions. This, in turn, enhances further biodiversity loss. This session addresses this understudied feedback loop by accounting for the biodiversity-related flexibility of ecological systems, which enables them to adjust to for example altered predation, prey availability, or abiotic conditions. Trait adjustment may arise from phenotypic plasticity, shifts in community composition or evolution. We invite discussions of results from experimental approaches, field measurements and mathematical modelling, ideally comprising two or more trophic levels. We will have a mixture of talks, posters, discussion groups, and open space for more informal working groups.

This session is organized by Dynatrait.

English

Detecting biodiversity in aquatic systems and studying processes that contribute to biodiversity changes require reliable tools for identifying and quantifying species and their traits. Advances in (semi-)automated imaging techniques for planktonic organisms allow processing of large numbers of individuals. Combined with image analysis through computer vision, machine learning, and/or deep learning, these techniques can be powerful tools for studying biodiversity at high temporal and spatial resolution. Several imaging and analysis approaches are under development and some are already being implemented. This session invites contributions presenting current approaches, method development, protocols, and studies that use imaging techniques to study biodiversity. In particular, the session will serve to discuss common approaches and limitations.

Session chair: Lutz Becks and co-chairs.

English