Adding iron to sea boosts deadly neurotoxin
By Staff Writers
Washington (AFP) March 15, 2010 — Adding iron to the world’s oceans to capture carbon and fight global warming could do more harm than good, as the mineral appears to boost the growth of a plankton that produces a deadly neurotoxin, a study published Monday shows. Researchers led by Charles Trick of the University of Western Ontario in Canada found that fertilizing the ocean with iron can boost the growth of Pseudo-nitzschia, a phytoplankton that produces a component of the neurotoxin, domoic acid. Humans who eat shellfish or crab that have ingested Pseudo-nitzschia could get amnesic shellfish poisoning (ASP), severe cases of which can cause neurological symptoms, including permanent, short-term memory loss, which gives the intoxication its name. Amnesic shellfish poisoning can also be fatal. For the study, which was published in the Proceedings of the National Academy of Sciences, the researchers examined water samples taken from open-ocean tracts in the sub-Arctic North Pacific Ocean where iron-fertilization experiments were conducted. They found that the population of Pseudo-nitzschia had doubled compared to controls, that adding iron to the water appeared to increase the amount of domoic acid produced by individual phytoplankton, and that the natural release of the toxin boosted further growth of the potentially harmful plankton. …
