The summer toxic blooms of blue-green algae (or cyanobacteria) were more intensive in the Gulf of Finland and the Baltic Proper in 2004 than in the previous year, according to latest studies by the Helsinki Commission.
Scientists, however, underline that there is no clear trend in the intensity of the blooms. The blooms in these areas were even more intense in 2002.
There is no data available on the total area covered by algal blooms in 2004 yet. However, in the summer of 2002, when the blooms spread around Gotland and were most intense in the Northern Baltic Proper and in the Gulf of Finland, the maximum area extent was over 110000 km2.
In the summer of 2003 the maximum area extent was also around 110000 km2, but most observations were made east and south-east of Gotland. The bloom then spread westwards along the Polish and Swedish coast to the Arkona Basin and Belt Sea.
Analysis of sediment cores has indicated that cyanobacterial blooms are as old as the brackish phase of the Baltic Sea, starting 7000 years B.C. It also shows that cyanobacteria pigments in sediment cores have increased in concentration since the 1960s, indicating a marked increase in bloom intensities during the last decades.
Since the mid-90’s, the strength of harmful and toxic cyanobacterial blooms have increased to levels to raise wide public concern. Currently, the noxious blooms annually limit the recreational and economic use of the Baltic, and moreover, represent a clear health risk for humans and domestic animals.
Follow up:
Phytoplankton biomass and species succession in the Gulf of Finland, Northern Baltic Proper and Arkona Basin in the year 2004
http://helcom.navigo.fi/environment/indicators2004/succession/en_GB/biomass/
Cyanobacterial blooms in the Baltic Sea http://helcom.navigo.fi/environment/indicators2004/cyanobacterialblooms/en_GB/cyanobacteria/
Cyanobacteria bloom index http://helcom.navigo.fi/environment/indicators2004/cyanobacteriaindex/en_GB/index/
Contacts
HELCOM Secretariat
Mr Juha-Markku Leppänen
Professional Secretary
Tel: +358 9 62202227
Fax: +358 9 6220 2239
Mr Nikolay Vlasov
Information Secretary
Tel: +358 9 6220 2235
Fax: +358 9 6220 2239