Pierre Regnier and Andy Dale

A transient reactive-transport model has been developed to simulate the effects of eutrophication and climate change at the centennial timescale. The overarching goal of the research was to predict whether future climate-dependent changes in temperature and ventilation of the Baltic Sea, combined with continued organic carbon loading, could enhance methane gas production and release from the seabed. Therefore, the model was designed to account for changes in bottom-water sulfate due to freshening of the Baltic, changes in organic matter flux triggered by variations in productivity and variations in bottom water temperatures. The model was applied at different locations in the Baltic Sea to forecast the increase in methane gas inventories.

Fig. 1. Projected change in methane gas inventory at a shallow site (30 m) in the Bothnian Bay. Dark blue: present-day gas inventory; Light blue: Gas inventory in 2100.

References

Dale, A., Flury, S.,  Regnier, P., Røy, H., Fossing, H., and Jørgensen B.B Coupling between methanogenesis, anaerobic oxidation of methane and δ13C distributions in gassy sediments from the Baltic Sea (Aarhus Bay). Geochimca Cosmochimica Acta, submitted.

Neumann, T. Climate-change effects on the Baltic Sea ecosystem: A model study, Journal of Marine Systems 81, 213–224, 2010.