Oceanologia (Jun 2003)
<i>Nodularia spumigena</i> blooms and the occurrence of hepatotoxin in the Gulf of Gdańsk
Abstract
Nodularia spumigena forms extensive summer blooms in the Baltic Sea. The occurrence of the blooms is determined by water temperature, light intensity and nutrient concentration; levels of nitrogen and phosphorus in particular are critical. The time of the seasonal maximum and intensity of the Nodularia bloomin the Gulf of Gdansk vary significantly from year to year. In2001 a rapid and massive proliferation of N. spumigenawas observed in late June - early July. The concentration ofnodularin in water ranged from 90 to 18135 µg dm-3and in lyophilised phytoplankton samples from 3000 to 3520µg g-1 d.w. (dry weight).Such a high concentration of toxin in the recreational watersof the Gulf of Gdansk constitutes a health risk for users ofbathing areas. In 2002, the N. spumigena bloom wasless dense, but lasted longer, with a maximum in late July- early August. In 2002 the concentration of nodularin did notexceed 12.6 µg dm-3 in water and 919 µg g-1d.w. in lyophilised phytoplankton samples. Other cyanobacterial toxins- microcystins and anatoxin-a - were also detected in the coastal waters ofthe Gulf of Gdansk.
