UNATTENDED MONITORING OF POTENTIALLY TOXIC PHYTOPLANKTON SPECIES IN THE BALTIC SEA IN 1993

Variabilities in chlorophyll a fluorescence, temperature and salinity in the surface were recorded unattended on board two merchant ships in the: Baltic Sea. When these recordings were complemented by automated water sampling, it was possible to analyze the phytoplankton species composition in 426 samples. In total, 22 potentially toxic phytoplankt on species or genera were detected. Nodularia spumigena was the only s pecies that formed extensive blooms. The system has proved to be an ef fective early warning method for exceptional and eventually harmful al gal blooms. The possibilities for using this method as an alternative, or a complement, to conventional methods in marine phytoplankton moni toring are discussed.