Ocean fertilization yields hope, uncertainty for global warming

Iron sulfate mixed with ocean water produces phytoplankton, which draw carbon dioxide from the atmosphere

In this story: Increased plant biomass, production A potential billion dollar market RELATED STORIES, SITES

From Don Knapp
CNN San Francisco Bureau Chief

(CNN) -- Scientists are trying to determine whether treating ocean water with iron sulfate is a quick fix for global warming or a Pandora's Box that could lead to further environmental problems.

Scientists and entrepreneurs alike see opportunity in the results of a mid-1990s experiment in which Moss Landing Marine Laboratories spread relatively small amounts of iron sulfate across a 100-square-mile patch of ocean.

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"By day four, five, the oceans had turned green," said Kenneth Coale, oceanographer and acting director of Moss Landing Marine Laboratory. "(It) had turned from what is an electric blue, characterizing the equatorial Pacific, to something bright green. You could smell the difference."

The iron-treated ocean rapidly produced tiny ocean plants called phytoplankton that draw carbon dioxide, a greenhouse gas associated with global warming, from the atmosphere. Coale estimates the experiment increased plant biomass by a factor of almost 40 and plant production by a factor of five or six.

"In nine days, we had grown thousands of tons of phytoplankton and biomass and drawn down atmosphere carbon dioxide," he said.

Lab director John Martin originally proposed the experiment. He was widely quoted as saying, "Give me a half tanker of iron, and I'll create an ice age,".

But Martin died before getting to test his theory of whether organisms feeding on that much phytoplankton could rob the ocean of oxygen and in turn, kill fish.

As the U.S. Department of Energy monitors the experiments, it hypothesizes that carbon may be locked up and sent to the bottom of the ocean or re-released back into the atmosphere.

"We can turn the ocean green, but we really don't have a clue as to where the carbon goes," said Jim Bishop of the Department of Energy.

Until they figure that out, researchers say it may be risky to try to turn down the global thermostat by turning up phytoplankton growth.

Coale's group will return to the ocean for another 100-square-mile iron fertilization experiment in about a year.

"We need to understand whether this is the way that nature turned on and off global warming in the past, and we need experiments of a relatively large scale in order to answer those questions," Coale said.

Also taking to the waters is Greensea Venture Inc. and chemical engineer Michael Markels, who will spread his proprietary mixture of chelated iron over 5,000 square miles of ocean in a $7 million experiment.

Markels said he's interested as much in product development as academic research, but at stake is a potential market worth billions of dollars in "credits" for carbon dioxide-producing industries.

Industry pays from $30 to $100 to rid its exhaust gases of carbon dioxide, but Markels believes the greenhouse gas can be removed for about $2 a ton by treating the oceans with iron.

"We've thought coal companies might be interested in this because they could sort of have a little license attached to their coal that says, when you burn this coal, no net CO2 would go into the atmosphere because we've already taken it out," Markels said.

Markels said he'll ask academic researchers, including Moss Landing Marine Laboratories, to participate in the evaluation of his experiment, but Coale may be leery of Markels' approach to global warming solutions.

"Iron fertilization for geo-engineering, or fish production, has been driven by a kind of quick-buck philosophy that is not necessarily sensitive to downstream effects," he said.

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U.S. Department of Energy
Moss Landing Marine Laboratories

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