Program

Harmful algae bloom (HAB) is a phenomenon of rapid proliferation of harmful microalgae that caused water discoloration or toxicity. Nutrients are known as one of the factors that contribute to HAB events. In 2001, Alexandrium minutum was reported for a poisoning event related to paralytic shellfish poisoning (PSP) in Sungai Geting, Kelantan. A study was undertaken to determine the phytoplankton community in relation to the nutrient variability and to investigate the distribution of the potential harmful microalgae. Ten genera of potentially harmful microalgae (13 species) were documented throughout the 18-months sampling. Alexandrium minutum remained the major toxic inhabitant in the lagoon. Alexandrium tamiyavanichii, another potent saxitoxin producer, was also found in the water. Several bloom-forming dinoflagellate species that cause fish kills were encountered in the lagoon: Alexandrium pseudogonyaulax, Ceratium furca, Peridinium quinquecorne, Gonyaulax verior, Akashiwo sanguinea, Noctiluca scintillans, Scrippsiella sp. Diarrhetic shellfish toxin-producing species, Dinophysis caudata was found occasionally. Harmful diatoms such as Pseudo-nitzschia spp. (Amnesic Shellfish Poisoning) and Chaetoceros spp. (fish kill) were also encountered in the waters. Nutrients in this lagoon are rich and contributing by sewage, small industries, fisheries and aquaculture run off and discharge. Shift in species contribution and reduction in phytoplankton biomass in this lagoon was attributed to the changes in nitrogen to phosphorous ratio. This study has provided a baseline reference on harmful microalgal diversity in the lagoon to understand the linkage between macro-nutrients and phytoplankton biomass.