Global warming breeds toxic seas

Toxic algae blooms, such as the "red tides" which pollute the oceans and kill fish, could increase in number and severity because of global warming, a researcher warned yesterday.

The study of one organism responsible for such blooms caused serious illness to Dr JoAnn Burkholder, of North Carolina State University, and one of her colleagues. Dr Burkholder discovered a new microscopic marine organism which is responsible for the deaths of millions of fish each year on the east coast of the United States. But she had to stop her research when toxins from the organism she was studying made her ill.

The university has since built a special isolation unit for handling the organism. It is a single-celled creature known as a dinoflagellate. During its life the organism goes through at least 19 stages which makes it difficult to tie it to any given episode of fish death. Although it is an animal, it "steals" green coloration from algae, thus allowing it to ambush fish while masquerading as a microscopic plant. It can eat holes the size of five-pence coins in its prey.

Dr Burkholder warned that the global increase in harmful marine phytoplankton blooms over the past decade has coincided with reports of death and disease for fish and, in some cases, humans. But because the blooms appear only sporadically, they are difficult to study. As the climate warms, Dr Burkholder said, such blooms are likely to increase in number and toxicity.

Dr Burkholder issued the warning at the annual meeting of the American Association for the Advancement of Science in Baltimore.