TOXICITY OF BLOOMS OF THE CYANOBACTERIUM-TRICHODESMIUM TO ZOOPLANKTON

The marine filamentous bloom-forming cyanobacteria Trichodesmium thiebautii and T. erythraeum were collected at locations in the Carribean during Jan.-Feb. 1991. They were screened for toxicity using Artemia salina and several species of copepods, which were harpacticoid grazers, filter-feeding calanoides, or cyclopoid copepods. Approximately 50% of the 89 T. thiebautii samples caused > 50% lethality of A. salina, though none of the 16 T. erythraeum samples caused > 25% lethality. The T. thiebautii bloom samples were toxic to the calanoid and cyclopoid copepods and non-toxic to the harpacticoid grazers. In contrast the T. erythraeum bloom samples were not toxic to any copepods tested.