Analysing internal causality and sensitivity to derive coastal sea responses to varying climate and anthropogenic forcing Concept for an SFB at the University of Rostock Presented by Hans Burchard Leibniz Institute for Baltic Sea Research Warnemünde

Program of this presentation The Baltic Sea: a very special marine system Changing Baltic Sea Key questions of the SFB SFB Structure SFB Model Environment SFB Graduate School

Baltic Sea drainage area Mean freshwater run-off: m 3 /s

Dann kann aber doch fast gar kein Salz in der Ostsee sein ??? Baltic Sea monitoring

Salinity along monitoring section

Source: IOW Major Baltic Inflow in January Darss Sill: 19 m

Oxygen along monitoring section

A century of salinity in the Central Baltic Sea Graphics: Markus Meier (SMHI)

Phosphate feedback cycle in the Baltic Sea ecosystem

Have we understood triggers and limitations of cyanobacteria blooms ?

Cyanobacteria observation I – Central Baltic Sea (cell counts) Suikkanen et al no clear long-term trend no clear correlation between cyanobacteria and forcing factors

Cyaonobacteria observation II - whole Baltic Sea (from satellite) data by Kahru et al (graphics by Inga Hense, IOW) large inter-annual cyanobacteria fluctuations at small variations of forcing no clear long-term trend

We do not know the limiting and exitating factors for cyanobacteria blooms. Many knowledge gaps are due to substantial undersampling in time and space and in regulating parameters. As long as we do not know how it works today, we have no predictive capacity for future developments with respect to climate change and anthropogenic change.

Phosphate concentrations in winter surface layer in the Eastern Gotland Basin The anthropogenic influence changes: Reissmann et al., 2007

Baltic climate of the past 1000 years

Global climate change: emmission scenarios from IPCC 4th Assessment

Regional climate modeling at the Rossby Centre Global Regional Markus Meier (SMHI)

The coupled system RCAO Model domain, covering most of Europe and parts of the North Atlantic Ocean and Nordic Seas. Only the Baltic Sea is interactively coupled. The coupling scheme of RCAO. Atmosphere and ocean/ice run in parallel. OASIS  t mod  t coup ocean atmos rivers landsurf ice RCO RCA RCA: 44 km, 30 min RCO: 11 km, 10 min Coupling timestep: 3 h Döscher et al. (2002)

Regionalization is done for ”time-slices” from GCMs Present-day or a ”control” climate Climate scenario CO 2 Regional simulations Results archived from a GCM-run Time ( )( ) Markus Meier (SMHI)

Sea surface salinity Present climate Projection with the largest change RCAO-E/A2 5 psu Markus Meier (SMHI)

Present climate Projection with the largest change RCAO-E/A2 5 psu Sea surface salinity

Markus Meier (SMHI) Annual mean SST (in °C) in present climate (upper left), annual mean bias of simulated present climate compared to climatological data (upper right), and annual mean SST changes for the ensemble average (ECHAM4 and HadAM3H) of the B2 (lower left) and A2 (lower right) emission scenarios. The figure is taken from Meier (2006, Figs.13 and 14) with kind permission of Springer Science and Business Media. Sea surface temperature: +1.9 … +3.9°C

Markus Meier (SMHI) Mean number of ice days averaged for RCAO-H and RCAO-E: control (left panel), B2 scenario (middle panel), and A2 scenario (right panel). Figure is adopted from Meier et al. (2004). Sea ice changes

Key questions of SFB How can the abstract Baltic Sea response function and its interplay of linear and nonlinear processes be described in terms of logical, mathematical and numerical model components ? How does the character of Baltic Sea inflow events react to climate change and which impact do these modified inflow dynamics have on the biogeochemical cascades which they trigger ? How will the intensity and extent of cyanobacteria blooms react to climate and anthropogenic changes, and how will they interact with ecosystem dynamics of the Baltic Sea ? How will spatio-temporal changes in near-bottom temperature, salinity and oxygen distributions affect the biodiversity and extent of benthic fauna, and which consequences does this have for the benthic-pelagic coupling in the Baltic Sea ?

Key questions of SFB What is the role of redoxcline processes for overall biogeochemical cycles in the Baltic Sea and how are the communities and processes impacted by external forces (e.g., inflow events, turbulent mixing)? Final overarching question: To what extend does changing climate and anthropogenic forcing trigger ecosystem shifts in the Baltic Sea ?

Participating institutes Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Limnology of Stratified Lakes Leibniz Institute for Baltic Sea Research Warnemünde at the University of Rostock Institute of Biological Sciences University of Rostock Swedish Meteorological and Hydrological Institute, Nörrköping

Structure of the SFB P1: Pelagic processes – influence of light and inorganic carbon on primary production P2: Cyanobacteria blooms – dynamics and performance of diazotrophic cyanobacteria P3: Photorespiration, respiration, photoadaptation, and DNA micro-array P4:Diatom-dominated biofilmsT1: Biologically mediated particle and solute fluxes between sediment and the benthic boundary layer T2: Organisms’ functional capacityT3: Quantification of in-situ fluxes at the sediment water interface T4: Impact of turbulent transport intermittency on the biogeochemistry of pelagic redoxclines T5: Small-scale processes in the upper layers of the Baltic Proper M1: Particle-associated carbon turnover origin, decomposition and sedimentation M2: Structure and function of microbial communities in redox gradients M3: Biogeochemical element transformations and fluxes S1: Baltic Sea climate reconstructionS2: Analysis of the present Baltic Sea stateS3: Climate change and anthropogenic impact scenario simulations for the Baltic Sea

Spatial relation of the subprojects

SFB Model Environment

Logical and mathematical model Implementation into SFB-BGC Module and 1D testing Testing in 3D Ecosystem Model Process studies P, T & M System simulations S1, S2, S3 Analysis of process reproduction Process understanding required by models Interlinking between process studies and modelling system

SFB Integrated Graduate School: for all SFB Ph.D. students interdisciplinary teaching for all together modelling courses with 1D model system teaching in statistical methods exercises in field & lab methods soft skills … After this SFB, we will know far more about the Baltic Sea system than at present.