Gunnar Jakobs

Joint project (DFG) between Leibniz Institute for Baltic Sea Research Warnemuende and the Geoscience Center, Geobiology at the Georg-August-University of Göttingen:

Aerobic and anaerobic methane turnover in the water column of the central Baltic Sea  (Gotland Deep, Landsort Deep).

Dissolved methane is highly abundant in the deep anoxic water body of the central basins (Gotland-Deep and Landsort-Deep). Here the strong permanent haline stratification leads to large vertical redox gradients in the water column, which are perturbed by saline inflows from the North Sea. Though the surface waters of the Baltic Sea are considerably methane-oversaturated with respect to the atmospheric equilibrium, concentrations are low compared to the deep waters. Only little is known about the apparently very efficient oxidation in the water column by microbially mediated processes.

In the present work we use gas chemistry, microbiology and organic geochemistry to trace methane oxidation processes in the water column of the Gotland Deep and Landsort Deep. Assessing the importance of sulphate-dependent and -independent AOM in the Baltic Sea clearly requires further studies.