Oceanologia (Jun 2006)
Toxic <i>Nodularia spumigena</i> blooms in the coastal waters of the Gulf of Gdańsk: a ten-year survey
Abstract
In the Baltic Sea, summer blooms of the filamentous, nitrogen-fixingcyanobacterium Nodularia spumigena are favoured by high P concentrationsat low N:P ratios and a salinity range of 5-13 PSU. The bloomsare initiated by calm and sunny weather, an elevated surfacewater temperature and thermal stratification. The mass occurrenceof N. spumigena in coastal waters is a matter of special concern,as the cyanobacterium produces nodularin, a potent pentapeptidehepatotoxin. In the Gulf of Gdansk, the large-scale occurrenceof N. spumigena was recorded for the first time in 1994. Bloomsof a similar intensity occurred in 2001, 2003 and 2004. Nodularinconcentrations in freeze-dried bloom samples varied from 0.01to 4.01 mg g-1 d.w. In the coastal waters of the Gulf of Gdańsk,cell-bound nodularin concentrations in 2004 and 2005 attainedmaxima of 25852 ± 107 µg dm-3 and3964 ± 125 µg dm-3, respectively. Microscopic analysis revealedthe presence of diverse N. spumigena forms, with the dominance of curvedfilaments in bloom samples. The results of in situ studies and remotesensing measurements indicate a high frequency and intensity of cyanobacterialblooms in the Gulf of Gdańsk in the last ten years.
