Community Research and Development Information Service - CORDIS

Development and fate of cyanobacterial blooms in the Baltic

Cyanobacterial blooms are characteristic for the Baltic Sea. They occur only during a relatively short period in summer but they can reach very high densities. Very little is understood about the factors that allow the development of these waterblooms or their often sudden disappearance.

During the first year of the project, we have found that phototrophic biomass was composed for 40-80% of picoplanktonic species that was responsible for 50-60% of the primary productivity. The remaining part was composed of colony-forming, filamentous, heterocystous cyanobacteria, mainly of the genera Nodularia and Aphanizomenon. These species have some properties that make them very important for the Baltic Sea water blooms. These species are all capable of diazotrophic growth (ie they can fix nitrogen and are therefore independent of combined sources of nitrogen). Another property of these organisms is that they possess gas vesicles that provide them with buoyancy. It was shown that during calm days these organisms float rapidly to the surface, where they experience optimal light conditions.

Contact

Lucas STAL, (Head of Department)
Tel.: +31-113-577497
Fax: +31-113-573616
E-mail
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