Workpackage 5: Bio-geo-chemical processes and primary production in the Baltic Sea.

WP5 coordinator is Juris Aigars, Dr. geogr., director of Latvian Institute of Aquatic Ecology. WP5 participants are researchers of Latvian Institute of Aquatic Ecology and Faculty of Biology UL.

WP aims to develop forecasts of the climate change impact on bio-geo-chemical cycles in the Baltic Sea ecosystem. Observations of the recent decades witness that climate change significantly alternates hydrological regime of the sea. With the North Sea water inflows becoming weaker and less frequent, anoxic areas of the seabed increase in size. Shift of the hydrological regime impacts also environmental quality in sub-regions where oxygen deficiency has not been yet observed: like the Gulf of Riga. Further strengthening of this impact may be expected. Changes in ice conditions and seasonal weather will modify amount of plankton primary production and pelagic sedimentation. This, in turn, will influence turnover of substances in bottom sediments.

WP 5 tasks are:

• Identify experimentally border values of regime parameters causing abrupt changes in biogeochemical processes in water-sediment interface layer (Interface processes).
• Identify relationships among primary producer dynamics, abiotic factors controlling sedimentation and vertical flux of matter, by means of a seasonal field observation (Production and sedimentation).
• Apply forecasts produced by WP1 and WP2 and experimentally determined critical values (tasks WP5a, WP5b) to develop and calibrate bio-geochemical model of the Gulf of Riga (Marine bio-geo-chemical model).
• Forecast changes in the Baltic Sea environmental quality and productivity till 2100 by use of the developed model (Forecast of marine ecological quality and productivity).
• Advice on necessary adaptation and impact mitigation actions in accordance with projections of marine environmental quality and productivity (Advice for adaptation).

WP 5 outputs will be:

• Information on critical values of regime-determining parameters causing significant modification of biogeochemical processes in the sea.
• Forecast of sedimentation pattern modification caused by climate change.
• Calibrated bio-geo-chemical model of the Gulf of Riga allowing forecasting of nutrient system evolution under various climate change scenarios.
• Projection of the Baltic Sea and the Gulf of Riga environmental quality and productivity till 2100.
• Set of scenarios on oxygen and nutrient conditions necessary for long-term forecast of ecosystem dynamics.
• Identified critical values of environmental parameters causing changes in marine environmental quality.
• Scientifically sound advice for stabilizing and mitigating coastal marine eutrophication under conditions of climate change.