MURSYS - Baltic Sea

the emblem of the BSH

MURSYS - Baltic Sea


Sweden (Annual Report 2003)

  County Administrative Board of Stockholm, Information Office for the Baltic Proper:
"Report on the activities at the Information Office for the Baltic Proper during 2003"



There were no large-scale algal blooms before July. Then came heat and high pressure, and around the 10th of July the first surface accumulations of cyanobacteria were noted at sea. The areas covered by those increased and in July and August there was on the whole more or less dense cyanobacterial surface blooms over the entire Baltic Proper. At the beginning of August strong winds mixed down most of those blooms into the water column. In the middle of August extensive blooms showed up along the southernmost Swedish coasts resulting in algae drifting ashore. The large-scale blooms decreased at the end of August. However, a major bloom showed up around Åland as late as during the second week of September. Also small, local accumulations occurred, especially at the end of summer and during the autumn, but also as late as in the beginning of December.
According to SMHI the blooms this year were more extensive than the blooms of 2002 based on their analysis of the 2003 satellite image interpretations and comparison with the results of 2002 (Figure 1)
The oxygen situation in the bottom waters of the Baltic Proper improved during the year. An inflow of North Sea water early in the year caused a considerable improvement in the oxygen contents in the southern and south-eastern deep basins up to and including the Gotland Deep. In the latter, the improvement took place in May and it was still noticed at the end of November. In the south-eastern parts, which may also be affected by weaker inflows of North Sea water, the situation was better with oxygen levels above 2 ml/L (2,86 mg/L) for most of the year. Still, the situation deteriorated somewhat also in those areas during the later part of the year.
The bird death has been observed along the Swedish Baltic coast also this year. The Swedish National Veterinary Institute took samples and tries to find out what causes the death. They try to find out whether it is caused among other things by deficiency diseases, virus infections or environmental toxins.

Figure 1a, File=17,4 KB

Figure 1b, File=20,2 KB

Figure 1: The pictures show the total number of days with surface accumulations at a given point (image pixel) in the Baltic in 2002 and 2003. A comparison between the years shows that the blooms this year were more extensive than last year. Source: SMHI.

The complete report is available on the internet at:


 © 2016 Bundesamt für Seeschifffahrt und Hydrographie Last Update: 19.04.2013 18:03:32  
 Print Version Home • Deutsche Version • Contact • Help • Federal Freedom of Information Act • Imprint