1. The carbon system in the Baltic Sea oceanography/marine chemistry Moa Edman Ph.D. student Department of Earth Sciences University of Gothenburg Supervisors: Anders Omstedt and Leif G. Anderson E-Mail: moa.edman@gvc.gu.se Homepage: www.oceanclimate.se

2. In general: My research concerns numerical modeling of the acid-base (pH) balance in costal seas, and more specifically, in the Baltic Sea. I will use both numerical models and available data to analyze and understand the sensitivity and function of the carbon, and the general biogeochemical, system. Questions such as: How sensitive is the Baltic Sea region to acidification? What consequences should we expect in the Baltic Sea, and if possible, plan for under a changing climate?

3. The Baltic Sea carbon system 4carbon system parameters: A T C T fCO 2 pH

4. Planed projects: Perform a pH sensitivity study in the Baltic Sea to pinpoint the most important influences to the carbon system. Within Baltic-C: Validate the PROBE-Baltic model further with new data within Baltic-C Use the model to run scenarios. The scenarios will be based on different climate change developments, and their implications on land with biota, soil and limnic waters in the Baltic Sea region. The results will be evaluated and should give an overview of how the Baltic Sea carbon system might be affected by climate change.

5. This far: First project is a sensitivity study: What are the main influences on pH in the Baltic Sea? Data overview –Natural variations and range of pH Analytical calculations Box-model investigation –Steady state calculations for different sets of forcing –Investigating influences from land, from the atmosphere, and also from inflowing sea water. Transient model investigation –Numerical modeling with the PROBE-Baltic model. –The change of some key parameters are investigated in different scenarios. Scenarios are based on previous box-modeling.

6. Data overview: Map of the Baltic Sea, with station BY15.From top to bottom: Time series of surface pH-data, annual pH means and standard deviations, and monthly pH means with standard deviations.

7. Example of analytical result:

8. …and the work continues In general: I hope to work with further improvement in the field of biogeochemical ocean modelling Interesting unknowns! The end