The hydrographic-hydrochemical state of the Baltic Sea in 2010

The article summarizes the hydrographic-hydrochemical conditions in the western and central Baltic Sea in 2010. Based on meteorological conditions, the horizontal and vertical distribution of temperature, salinity, oxygen/hydrogen sulphide and inorganic nutrients are described on a seasonal scale.

The year was characterized by a long and cold winter 2009/2010 and a warm summer which is also reflected in the surface water temperature.

In 2010, barotropic inflow events with estimated volumes between 100 and 200 km³ took place five times: in January/February, in July, in September, in October/November and in December. However, they were not able to ventilate the deeper basins of the Baltic Sea. The barotropic inflow of November/December 2009 was only able to oxygenate the Bornholm Basin and could be detected within the halocline of the eastern Gotland Basin in March 2010. In the deep water of the eastern and northern Gotland Basin, the stagnation period is continuing undiminishedly. Compared with the end of the previous long stagnation period in 2002, the 2010 ammonium concentrations of the Gotland and Farö Deeps are reached again or even exceeded. Also phosphate concentrations are in the same order of magnitude.

Dr. Günther Nausch