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)
Summary of Baltic Sea Monitoring
In general the 2006 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
Zndiss. 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
increase was observed with depth in the central Baltic, a hint for the stabilisation of the
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 western Baltic Sea
(BLMP-stations) still not show a significant
temporal trend (1998 to 2006). In 2005 a new geochemical mapping of surface sediments of the
Arkona Basin was performed. The results are presented now in a Diploma-Thesis (Kowalski, 2007).
The results of the investigations show a remarkable decrease of heavy metal concentrations in
comparison to data from the 80th of the past century.