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for National Geographic News
March 27, 2009
A giant experiment went awry at sea this month.
Shrimplike animals devoured 159 square miles (300 square kilometers) of artificially stimulated algae meant to fight global warming—casting serious doubt on ocean fertilization as a climate-control tool.
For years, scientists have proposed supercharging algae growth by dumping tons of iron into the ocean.
Iron is a necessary element for algae photosynthesis—the process by which the plants convert sunlight into energy—but it is relatively rare in the ocean.
(Related: “Plan to Dump Iron in Ocean as Climate Fix Attracts Debate”.)
Algae suck carbon dioxide (CO2), a greenhouse gas that contributes to global warming, out of the atmosphere. The algae then generally fall to the seafloor—sequestering the CO2 indefinitely.
About a dozen such “iron fertilization” experiments have already been done—with mixed success.
But experts have warned of unintended consequences, such as unpredictable reactions in the ecosystem.
And that’s just what happened during a recent, large-scale iron dump in the South Atlantic, the Alfred Wegener Institute in Germany announced this week.
With the greenish, crystalline look of a pulverized windshield, ferrous sulfate is commonly given to iron-deficient humans.
It’s also the iron of choice for boosting algae growth.
Working aboard the German research vessel Polarstern, German and Indian scientists in recent weeks mixed ten tons of ferrous sulfate with seawater. The team then pumped the artificially enhanced water back into the Atlantic outside Argentina’s coastal waters.
As expected, the experiment created a massive, CO2-eating algae bloom.
But it was the wrong algae.
The blooms were mostly tiny haptophytes, not the larger diatom algae the team had expected.
The smaller algae variety is typically found only in coastal waters, and it’s a favorite food of tiny shrimplike crustaceans called copepods.
The copepods wolfed down the algae shortly after the new South Atlantic bloom appeared—and a potential weapon against global warming quickly disappeared.
“The fact that they are rapidly eaten by marine animals is not good for carbon sequestration,” said Ulrich Bathmann, head of bioscience at the Alfred Wegener Polar and Oceanography Institute (AWI) in Bremerhaven, Germany, who was involved in the experiment.
Good News? Bad News?
Experts not part of the new experiment are divided on what the results mean.
“The new finding here is that the standard calculations of ‘the number of tons of iron in equals the number of tons of carbon out’ probably don’t actually work,” said Gabriel M. Filippelli, an earth sciences professor at Indiana University-Purdue University Indianapolis.
“This calls into question the efficacy of iron fertilization as a solution to global warming.”
(Read about other global warming solutions.)
Iron-fertilization supporters, though, remain hopeful.
“These results neither argue for nor against iron fertilization as a carbon-sequestration strategy,” said Kenneth Coale, director of California-based Moss Landing Marine Laboratories.
Moss Landing scientists created a similar, though smaller, algae bloom in Antarctic waters in 2002.
On the bright side, Coale said, the experiment adds to evidence that iron can stimulate large-scale algae growth. It’s not clear that in every instance animals would gobble up the carbon-sucking plants, he says.
Other experiments have also had better success at sequestering carbon, Coale added.
And regardless of its carbon-sequestration success or failure, Coale said, at least the South Atlantic experiment did not damage the local ocean environment—which would have been a more serious black mark on iron fertilization.
The consensus, though, seems to fall somewhere on the fence, said environmental scientist Andrew Watson of the University of East Anglia, U.K.
The recent experiment, Watson said via email, “shows that we still haven’t learned by any means all there is to know about the effects of iron on marine ecosystems and the carbon balance in the oceans.”
By Caroline Schultz, Executive Director
Once again the polar bear made headlines when the U.S. Department of the Interior announced it had listed this iconic species as “threatened.” This was a long-overdue move lauded by environmental groups and a notable contrast to Canada’s weaker “special concern” designation.
This development came just weeks after the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) declared the Canada warbler a “threatened” species. Long considered common in our boreal forest, Canada warbler populations have plunged 45% over the past four decades. This pretty, active little bird is now yet another name on a list.
What’s worse, Dalton McGuinty’s Liberal government in Ontario significantly set back the protection of Ontario’s biodiversity last week by quietly proposing that the logging industry, active across 45% of the province, be exempt from the provisions of its own Endangered Species Act (ESA).
The roster of endangered species grows every year due to the disturbingly repetitive cycle of threats from habitat loss, pollution and climate change both in lower latitudes as well as the north. As our winters become shorter and milder, frogs, for example, emerge from hibernation prematurely – a certain death sentence as their food source, adult crickets and other bugs, remains buried underground as larvae and eggs until spring.
The Ontario government’s move, announced at the same time as the polar bear decision, is a devastating reversal. In May 2007, when Queen’s Park unveiled its new ESA, Ontario Nature and a coalition of conservation groups applauded the law as a triumph of forward-looking legislation. It made Ontario a leader in North America in terms of protecting the most vulnerable plants and animals across a wide variety of ecosystems, from temperate forests in the south to tundra in the north — home, incidentally, to about 1,000 southern Hudson Bay polar bears, or 7% of the Canadian total.
The need for such protections is indisputable. Ontario provides habitat for globally threatened species such as the spotted turtle, the cerulean warbler and the wolverine. Woodland caribou populations have declined enormously due to logging. And of the 24 reptile species indigenous to Ontario, 15 are now at risk, including six of the province’s eight species of hard-shelled turtles. Indeed, among those plants and animals for which population trends are well documented, more than 75% — a shocking statistic — have either disappeared from Ontario or continue to decline. More alarming still is that a growing number of once common species – the common nighthawk, the olive-sided flycatcher – are now being added to the list of species at risk.
The new Act boosted the number of protected species from 42 to nearly 200, granted automatic habitat protection for endangered and threatened species (a first), required mandatory recovery efforts for those species and provided conservation incentives to private landowners.
We believe a blanket exemption for the logging industry will do nothing less than defeat the purpose of the Act. If this long overdue and desperately needed piece of legislation isn’t effectively implemented, the future will be bleak for Ontario’s at-risk species and may well lead to further decline among boreal forest species, such as the woodland caribou. Allowing the forestry industry to continue its business-as-usual methods could easily prove to be the tipping point for iconic and little known species alike.
We urgently need federal and provincial policies, legislation and enforcement to protect our wildlife, and not just in the far north. If our neighbours to the south can recognize the magnitude of this crisis, then so can we.