Leibniz-Institut für Ostseeforschung, Warnemünde
(IOW) (Baltic Sea Research Institute, Warnemünde)
Bundesamtes für Seeschifffahrt und Hydrographie, Hamburg, Rostock
(Federal Maritime and Hydrographic Agency of Germany, Hamburg, Rostock)
by Günther Nausch, Rainer Feistel, Lars Umlauf, Klaus Nagel, Herbert Siegel
(Summary of Baltic Sea Monitoring)
In general the 2007 results of heavy metal concentrations in the Baltic Sea revealed no pronounced changes compared to previous years.
Regional and temporal limited variations as observed in 2006 for Cudiss, which have been observed periodically in the western Baltic also for the other metals, have been attributed to the changing enrichment of suspended matter in the water column, released by wind induced mixing up to the ground level. During sample filtration only particles <0.4 µm were restrained, while particles >0.4 µm
passed the filter.
Short-term changes induced during the main saltwater inflow event in February 2003 were only reflected in the trends "Below Halocline" for Cddiss, Cudiss, and Zndiss. Elevated Pbdiss levels in the Western Baltic are possibly a result of sample contamination. Stagnant conditions
with anoxia and decreasing dissolved trace metal conditions below the oxic-anoxic interface were noticed in the near bottom layer of the Bornholm Basin at 80 m depth, below ~140 m in the Gotland Deep and below 100 m in the Landsort Deep. For the contents of CdSPM, CuSPM and ZnSPM an increase was observed with depth in the central Baltic, a hint for the stabilisation of the stagnation period.
Altogether the saltwater inflow event in 2003 had influenced the trace metal long term trends in the deepwater of the central Baltic Sea. Now there is another chance to study changes in trace metal concentrations during the stabilisation of an anoxic deep water body as well as the "feedback mechanism" on the trace metal concentrations in the surface water body. Heavy metal concentrations in surface sediments of the BLMP-stations varies in between the known ranges and differs for the investigated sub-areas, but still not show a significant temporal trend over the whole period (1998 to 2007).
The complete report "Die Schwermetallsituation in der Ostsee im Jahre 2007" together with the report "Hydrographisch-chemische Zustandseinschätzung der Ostsee im Jahre 2007" is available in German as no 72 of the series "Meereswissenschaftliche Berichte (Marine Science Reports) of the IOW " on the internet at: