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Algae "Techno-Fix" Found Toxic to Sea Life

Toxic troubles for climate 'fix', March 16, 2010

Fertilising the oceans with iron to absorb carbon dioxide could increase concentrations of a chemical that can kill marine mammals, a study has found.

Iron stimulates growth of marine algae that absorb CO2 from the air, and has been touted as a "climate fix".

Now researchers have shown that the algae increase production of a nerve poison that can kill mammals and birds.

Writing in Proceedings of the National Academy of Sciences, they say this raises "serious concern" over the idea.

The toxin - domoic acid - first came to notice in the late 1980s as the cause of amnesiac shellfish poisoning.

It is produced by algae of the genus Pseudonitzschia , with concentrations rising rapidly when the algae "bloom".

Now, its presence in seawater often requires the suspension of shellfishing operations, and is regularly implicated in deaths of animals such as sealions.

Domoic acid poisoning may also lie behind a 1961 incident in which flocks of seabirds appeared to attack the Californian town of Capitola - an event believed to have shaped Alfred Hitchcock's interpretation of Daphne du Maurier's The Birds in his 1963 thriller.

Carbon focus
Over the last decade, about 10 research projects have investigated iron fertilisation, with mixed results.

But only two of them measured domoic acid production, and only then as an afterthought, explained William Cochlan from San Francisco State University, a scientist on the new project.

"We had a number of major aims in this work; but one of them was to ask 'do you normally find the species of algae that produce domoic acid, are they producing domoic acid, and will production be enhanced by iron?'," he said.

In studies conducted around Ocean Station Papa, a research platform moored in the north-eastern Pacific Ocean, the answers to all three questions turned out to be "yes".

Pseudonitzschia algae were present naturally; they were producing domoic acid, and experiments showed that production increased during fertilisation with iron and copper.

Also, under iron-rich conditions, the Pseudonitzschia algae bloomed at a rate faster than other types.

The levels of domoic acid in iron-enriched water samples were of the same order as those known to cause poisoning in mammals in coastal waters.

Ailsa Hall, deputy director of the Sea Mammal Research Institute at St Andrews University in Scotland, said that domoic acid poisoning was already becoming a regular occurrence in some parts of the world.

"Ever since 1998 we've seen regular episodes of mass mortality and seizures in sea lions on the US west coast," she said.

The toxin accumulates in animals such as fish that are themselves immune.

"We've seen it in seals, pelicans and harbour porpoises; it does depend on how much they eat, but if a sea lion or a pelican eats its way through a school of contaminated anchovies, then that would be enough," Dr Hall told BBC News.

Domoic acid's effect on other species was unknown, she said, but it would be reasonable to think it would also affect marine mammals such as whales.

Whether iron fertilisation ever will be deployed as a "climate fix" is unclear.

The last major investigation - last year's Lohafex expedition - found that despite depositing six tonnes of iron in the Southern Ocean, little extra CO2 was drawn from the atmosphere.

Nevertheless, one company - Climos - aims eventually to deploy the technique on a commercial basis.

A Climos spokesman agreed that further research on domoic acid production was needed.

"Moving forward, we need to understand exactly how deep-ocean phytoplankton respond to iron, be it naturally or artificially supplied; whether and in what situations domoic acid is produced, and how the ecosystem is or is not already adapted to this," he said.

For William Cochlan's team, the potential impact on sea life is something that regulators and scientists must take into account when deciding whether to allow further studies or deployment.

"We saw some literature going around with claims like 'there is no indication of toxicity to sea life' - well, if you don't measure it, of course there's no indication, and we have to keep that kind of legalese out of science," he said.

"If the end goal is to use it to fight climate warming, then we have to understand the consequences for marine life."

Climate Quick Fix Could Create Toxic Algae Blooms, March 16. 2010
Pouring iron into oceans may combat global warming by feeding carbon dioxide-gobbling algae, but those algal blooms could become fountains of neurotoxin.

According to a small-scale test, iron-enriched waters favor the growth of Pseudonitzschia, an algae that pumps out brain-damaging domoic acid.

“The toxin per cell increases, and there’s an increased success against other species,” said oceanographer William Cochlan of San Francisco State University, co-author of the study, published March 15 in the Proceedings of the National Academy of Sciences. Pseudonitzschia “is out there in the most pristine environments. They produce low levels of toxin, so they’re not harmful. But if you add iron, and these cells proliferate, and produce more toxin per cell, then you have a problem.”

Oceanic iron fertilization is one of many proposed, planet-scale engineering solutions to climate change. Others include shrouding Earth in sun-reflecting aerosol particles, manufacturing CO2-absorbing artificial trees, and pumping CO2 into underground reservoirs.

Critics say these geoengineering schemes are untested, unpredictable and could have disastrous consequences — if, that is, they even work. Proponents say geoengineering should at least be considered, if only as a last-ditch tactic. Both generally agree that more research is needed.

Iron-fertilization research, however, is caught in a catch-22. It’s impossible to know large-scale effects without large-scale testing, but large-scale testing is limited by concerns about the effects.

The United Nations has declared a moratorium on oceanic iron-fertilization studies, and the International Maritime Organization has also limited research. But some companies and countries are pushing for restrictions to be lifted. In the case of a joint Indian-German expedition that fertilized 115 square miles of ocean in 2009, the restrictions have already been ignored.

The new report falls squarely into the middle of this fight.

“There’s an absolute need for remedies involving carbon sequestration, but they have to have a scientific foundation. At this point, iron fertilization doesn’t have that,” said Cochlan.

Cochlan’s team, led by University of Western Ontario phytoplankton specialist Charles Trick, added iron to tanks of water taken from the Gulf of Alaska, in an area where earlier researchers had conducted iron fertilization experiments.

They found that Pseudonitzschia, a common genus of algae, thrived on the iron. Pseudonitzschia at first accounted for a small fraction of algae and plankton in the water, but soon made up 80 percent of some tank populations.

Pseudonitzschia appears to benefit from its ability to produce domoic acid, which binds with iron and can then be reabsorbed by the algae. But unfortunately for other organisms, domoic acid is a potent toxin.

Cochlan, who previously studied a massive 2004 Pseudonitzschia bloom off the coasts of British Columbia and Washington, said the ecological consequences of an iron-fertilization-fed bloom could be profound, killing large numbers of animals and creating a steady injection of domoic acid into marine food chains, where it could accumulate in fish consumed by people. In humans, domoic acid produces permanent, short-term memory loss, and can even be fatal.

“Eventually, the toxicity subsides when the cells die. But doing a sustained iron enrichment experiment would mean that you’d want to keep these blooms going continuously,” said Cochlan.

The researchers warned against drawing absolute conclusions from a small-scale study. But even if preliminary, the findings do suggest that researchers who’ve suggested that Pseudonitzschia could only bloom along coastlines, and not on the open sea, were wrong.

Later this month, scientists and policy experts will meet in Asilomar, California, to discuss geoengineering risks and regulation. The meeting is organized by the Climate Response Fund, a nonprofit supporter of geoengineering research. Its director is Margaret Leinen, the former chief science officer of Climos, a San Francisco iron-fertilization company founded in 2005. Climos originally planned to sell fertilization-based carbon offsets, but after being criticized for jumping ahead of science has re-purposed itself as a research contractor.

“If domoic acid is produced by artificially stimulated ocean iron-fertilization blooms, it is likely produced during natural ones as well,” Climos said in a statement March 15. “We need to understand exactly how deep-ocean phytoplankton respond to iron, be it naturally or artificially supplied, whether and in what situations domoic acid is produced, and how the ecosystem is or is not already adapted to this.”

A key difference between natural and artificial iron supply is location, Cochlan said. There have not been any Pseudonitzschia blooms in the open ocean where iron fertilization is being considered.

“You’re going to change the base of the food web,” he said. “Going ahead with experiments like these without knowing what’s up the chain is foolhardy.”