Iron fertilization boosting toxin-producing algae growth in open ocean: Study

WASHINGTON - A new study has revealed that certain toxin-producing algae are incredibly responsive to iron, often becoming dominant in algal blooms that result from iron fertilization.

Blooms of diatoms in the genus Pseudo-nitschia, which produce a neurotoxin called domoic acid, are a regular occurrence in coastal waters.

During large blooms, the algal toxin enters the food chain, forcing the closure of some fisheries (such as shellfish and sardines) and poisoning marine mammals and birds that feed on contaminated fish.

Iron fertilization of the oceans has been suggested as way to reduce atmospheric concentrations of carbon dioxide and thereby combat global warming.

“It is much easier to break an ecosystem than it is to fix one. In light of these findings, we should redouble our efforts to reduce carbon emissions, the primary culprit for ocean ecosystem damage worldwide,” said Kenneth Coale, director of Moss Landing Marine Laboratories.

Mary Silver, professor emerita of ocean sciences at the University of California, Santa Cruz, noted that blooms of Pseudo-nitschia must occur naturally in the open ocean as a result of iron deposited by dust storms, volcanic eruptions, and other airborne sources.

“It is a natural phenomenon and likely has been for millions of years,” Silver said.

“But those are sporadic occurrences. To do iron enrichment on a large scale could be dangerous because, if it causes blooms of Pseudo-nitschia, the toxin might get into the food chain, as it does in the coastal zone.”

The findings are reported this week in the Proceedings of the National Academy of Sciences. (ANI)