Second Circular

The Baltic Sea Science Congress invites marine scientists focused on research questions related to the Baltic Sea or similar coastal sea systems to share their results on this international and interdisciplinary platform.

Please note that we explicitly invite scientists also working in other coastal seas than the Baltic Sea to present their results as long as they are of general relevance.

In order to focus the discussions, we identified four main session topics for the upcoming congress:

Session 1 (S1) Dynamics of gradient systems

Climatic, physical and chemical gradients are characteristic for the Baltic Sea, determining the ecosystem structure and functioning. In addition, human population density and land-use exhibit strong gradients. As a result, both, anthropogenic impact on as well as biotic structure of the Baltic Sea ecosystem differ broadly between its basins. These differences must be understood and taken into account when predicting the effects of global change. This session focusses on interdisciplinary studies on all aspects of gradient driven regional specifics of coastal seas with respect to ecosystem structure and functioning including:

• seasonal aspects of succession and trophic interactions, including their meteorological preconditions, physico-chemical driving forces and their geological record;
• oceanographic patterns shaping spatial distribution of and interaction between species;
• population structure including reproduction biology, population genetics and niche structure;
• the importance of hot events i.e. short term high intensity impacts such as storm surges, erosion driven nutrient inputs, but also periods of ice cover.

From the biological point of view, the theme explicitly addresses research on organisms of all trophic levels. Oceanographically, the theme focusses on short-term variability and differences in seasonality between the Baltic Sea basins with respect to physical and biogeochemical factors. From a meteorological point of view, the session is asking for contributions considering gradients in wind field, irradiance, precipitation seasonality and all aspects of sea ice.

Session 2 (S2) Processes that affect coastal sea systems

Coastal seas like the Baltic Sea undergo constant and direct influence from land. Forcing conditions for physico-chemical, biological and geological processes may change on very small time and spatial scales. Therefore, the Baltic Sea or similar seas may serve as a model and testing ground for investigating important processes in more detail. As a contribution to this session, we invite presentations that highlight recent findings on single or interacting processes that influence coastal seas in large and may focus on one or more of the following aspects:

• Turbulent mixing and other important physical processes, like upwelling: What is the linkage between geographical /physical conditions and the occurrence of hot-spots? What are the consequences to matter cycles, energy fluxes or sediment dynamics?
• Food-web interactions, biogeography and ecosystem function: What are the recent findings on the physiological performance and ecology of aquatic organisms from microbes to mammals influencing food-web structure and biodiversity? Do possible changes in food-web processes or species interactions affect the system?
• Matter fluxes and geochemical interactions: What do we learn from the Baltic low carbonate saturation for other ocean systems in terms of responses and effects of their carbonate systems? How do the relatively low salinity and biodiversity of the Baltic Sea affect biogeochemical processes and ecosystem services? Is the resilience of brackish systems naturally lower to anthropogenic pressures?
• Interaction atmosphere-ocean: Which specific processes are effective in the interaction of ocean and atmosphere? What role has the atmosphere in transporting and modifying substances that might affect processes in the ocean? What is triggering the feedback from the ocean to the atmosphere in detail, and what are the resulting effects? What do we have to consider in atmosphere-ocean interaction considering that the atmosphere is connecting an enclosed marginal sea to a much wider area? How does sea-ice influence the interaction?

Session 3 (S3) Past and future changes

In this session, changes on time scales from interannual to millennial in the sea, atmosphere and land surface will be studied. Oceanographers, meteorologists, chemists, biologists, and geologists are invited to join this interdisciplinary session in order to present and discuss latest results from environmental reconstructions, observations, and models of the Baltic Sea for the past, present, and the future.
The session addresses the detection and attribution of observed and modeled changes in the Baltic Sea and its catchment with respect to

• Changes in frequency and intensity in biogeochemical cyclicity;
• Changes  in relative sea-level;
• Changes in coastal morphogenesis;
• Changes in biodiversity, including aspects of biological invasions.

Results from instrumental measurements and historical data as well as interpretations of proxy-data from sedimentary records are welcome.

Session 4 (S4) Coastal seas and society

The Baltic Sea is knowingly under severe anthropogenic pressures. The environmental impacts stemming from human activities at sea, in the coastal areas or the catchment make the Baltic Sea a globally significant showcase of environmental management, exemplifying the difficulties in balancing utilization and protection of marine resources. In this broadly defined session, we aim to combine contributions covering all aspects of the interaction between society and the coastal sea, for example:

• Anthropogenic uses and interventions in coastal and marine systems such as off-shore engineering, tourism, energy production, extraction of minerals, maritime transport, and aquaculture;
• Studies on “hazardous” events, e.g., toxic algae blooms, naval accidents, extreme weather, flooding;
• Studies on state and impact of coastal and maritime planning, e.g. engineering, wind parks, resource extractions, fishery, transportation, and their cumulative effects on the ecosystem;
• Studies on contaminants, pollutants, microplastics, including the development of analysis methods for new substances, and studies on the interaction between chemicals, microplastics, and the food chain. Investigations on temporal trends and regional differences are also welcome;
• Implementation of marine and coastal policies: MSFD descriptors and indicators as well as development and evaluation of new indicators that can better help us to understand, monitor and assess the environmental status;

Cross-cutting session 1 (CCS1): Hypoxia

Hypoxia is one of the most severe threats to the Baltic Sea. To thoroughly understand all related processes is an ongoing task, especially what determines the extent and duration of oxic-hypoxic conditions. We are looking for new results explaining the development of hypoxic areas as well as for reports on process studies at hypoxic-oxic boundaries.

Cross-cutting session 2 (CCS2): Major Baltic Inflows

Contributions regarding processes and phenomena associated with recent salt-water inflows are requested: The major salt-water inflows starting in 2014 had different effects compared to such major inflow events in the past. What happened following this inflow? How did the small inflow events following later change the effects (geographically and in terms of geochemistry) of the major inflow?

Cross-cutting session 3 (CCS3): Monitoring / Observation / Assessment

This theme will present contributions highlighting new monitoring and assessment concepts and the necessary tools for implementing them. This may include modeling, operational oceanography and observational approaches like sensor development and in situ technology, autonomous and moored technology, gliders, ROVs, remote sensing, and general contributions to new monitoring strategies.

Cross-cutting session 4 (CCS4): Influences of the catchment

Contributions considering land-ocean interactions including hydrology are welcome: role of coastal processes influencing enclosed marine systems, and vice versa; effects of ground water inflow and river drainage to matter fluxes on changes in system structure and subsequent variations in energy budget; effects of riverine nutrient inputs and eutrophication, atmospheric inputs; regional differences of these processes in the Baltic Sea.