The threat of harmful algal blooms (HABs) in the polar water: a revisit

Abstract

While phytoplankton productivity and the risks of eutrophication in polar waters have been widely studied in recent years, the threat of harmful algal blooms (HABs) has not yet been thoroughly investigated. A commonly known harmful microalgal species, Alexandrium tamarense, has been successfully isolated and identified from water samples taken from Drake Passage during a survey in December 2001. Trace quantities of algal toxins, for example, saxitoxins and gymnotoxins, were also detected from shellfish samples collected off the coast of King George Island of the South Shetland Islands in 1993-4. Results obtained from Antarctic waters are comparable to those obtained in August 1999 in the northern Bering Sea and the Beaufort Sea up to 78oN, in which both A. tamarense and A. catenella were identified. During the past decade, increased incidents of PSP intoxication in Alaska, USA have been reported. Hence, collected findings suggest that Alexandrium-related HABs are not only limited to temperate, tropical and subtropical regions, but also occur in polar regions. Further investigations on the relationship between distribution of Alexandrium spp. and the oceanographic conditions in Arctic and Antarctic waters, and the similarity of toxicity and genotypes for various strains of Alexandrium spp. should be conducted to understand whether Alexandrium spp. originated from temperate regions and then spread to the Arctic and Antarctic, or the reverse. The influences of recent environmental changes to phytoplankton community in polar regions should also be revisited.