Oct. 2 (Bloomberg) -- Sydney’s worst dust storm in 60 years is giving scientists a chance to study how much an infusion of iron can alter the ocean’s ecosystems.

Satellite images from NASA breaking down chlorophyll levels in oceans around the world taken before and after last week’s dust storm show a marked increase in algae growth in the Tasman Sea. Researchers study such images to measure blooms of algae, the microscopic plants at the bottom of the ocean food chain.

Gale-force winds that ripped through Sydney last week may have dumped a million tons of iron-rich topsoil from Australia’s outback into the Tasman Sea and Pacific Ocean.

“The storm gives us an opportunity to understand the processes that drive iron fertilization,” said Christel Hassler, a biological oceanographer at the University of Technology, Sydney, in a phone interview. “It’s a good opportunity for us to jump on and look at what’s happening on a large scale in the field.”

Hassler has joined a team of research scientists who’ve been making weekly visits for the past three decades to Port Hacking, a coastal suburb of Sydney, to study if the dust storm has caused a change to this year’s seasonal marine blooms.

Algae “sustain the whole marine food web, so are really important for fisheries,” she said, explaining why they’re studied.

Algae are also known to absorb as much as 40 percent of carbon dioxide from the earth’s atmosphere, leading some scientists to speculate climate change could be mitigated by dumping iron into the world’s oceans.

Iron Fertilization

Natural iron fertilization can enhance the export of carbon to the deep ocean, according to a report in the January edition of the journal Nature based on research conducted by a team led by Raymond Pollard of the National Oceanography Centre in Southampton, England.

A new technology developed by Kirsten Heimann, a biologist at James Cook University in Queensland, and distributed by MBD Energy Ltd., a Melbourne-based alternative energy company, enables emitters to mix carbon dioxide with water to be pumped into tubes of algae. The algae, which absorb the carbon dioxide, can then be recycled to produce biofuel or to be buried in the seabed, where they can store the gas indefinitely.

A NASA image from Sept. 23 -- the day of the Sydney dust storm -- shows less than 1 milligram per cubic meter of algae growth off the southeastern tip of New South Wales state. A picture taken Sept. 29 shows concentrations as high as 15 milligrams along the southeastern coast and as much as 1 milligram further north and out into the Tasman Sea.

Algae Growths

While algal blooms are typical in the southern oceans at this time of year, algae growths further north than usual may be a result of last week’s dust storm, said Peter Thompson, a research scientist at Australia’s Commonwealth Scientific and Research Organization in Hobart, the capital of Tasmania.

“That dust event was huge,” Thompson said. “It probably blew dust into areas that are iron-limited, so that would cause a phytoplankton bloom.”

Algae levels may continue to rise in coming weeks, said Edward Abraham, a researcher who studied the impact of adding iron to oceans on algae growth while at the National Institute of Water and Atmospheric Research in New Zealand.

“When the iron is coming from dust, it takes some time for it to leach out into the water,” said Abraham, who now runs a Wellington-based company called Dragonfly that provides information to fisheries.

Though the benefits of algae growth for marine life are well known, Hassler and Thompson recommended against artificial efforts to boost iron content in an effort to store carbon because the outcome of such intervention isn’t yet known.

“Sometimes, the carbon also ends up staying in surface waters instead of sinking, so there’s no benefit,” Thompson said.

To contact the reporter on this story: Nichola Saminather in Sydney at nsaminather1@bloomberg.net

Last Updated: October 1, 2009 22:16 EDT