REPORT OF THEICES-IOC-SCOR WORKING GROUP ON GEOHAB IMPLEMENTATION IN THE BALTIC (WGGIB)

Nodularin is the main toxin existing in the Baltic HAB species. New nodularin analogues have been identified with Liquid Chromatography Mass Spectrometry methods. Recent laboratory experiments have revealed differences between phosphorus sources for the two main bloom-forming species, Aphanizomenon flos-aquae and Nodularia spumigena. A. flos-aquae relies mainly on dissolved inorganic phosphorus supplies, while N. spumigena grows equally well on intracellular phosphorus stores and an organic phosphorus compound. Phosphorus limitation of nitrogen fixation was found to have high placticity and no effects were found even at cellular N:P ratios exeeding 60:1.