Antarctic icebergs creating new ecosystem
May help absorb carbon dioxide in global warming
LOS ANGELES -- The proliferation of drifting Antarctic icebergs caused by rising temperatures is creating a vast new ecosystem of plankton and krill that may have the power to absorb some of the carbon dioxide that is driving global warming, scientists reported yesterday.
The researchers, led by oceanographer Kenneth Smith Jr. of California's Monterey Bay Aquarium Research Institute, found that these iceberg-associated communities may cover a significant portion of Antarctic seas.
The ecosystem uses photosynthesis to take carbon from the atmosphere and convert it into plant life and other forms of organic carbon that can be held in the ocean.
"I think it can be a substantial contribution" to reducing carbon dioxide levels, Smith said. "These things have been ignored forever."
As glaciers move across Antarctica, they accumulate nutrient-rich dirt and dust. When rising temperatures prompt the glaciers to break up, the resulting icebergs carry that material out to sea.
The researchers, who published their findings in the online version of the journal Science, analyzed two icebergs in the Weddell Sea .
They found that soil and other organic matter escaping from the icebergs provided nutrients and support for plankton and algae. Krill then fed on the plankton.
The scientists saw more seabirds near the drifting icebergs than in the open ocean. This iceberg-influenced zone extended more than 2 miles into the ocean surrounding the drifting ice.
"While icebergs may be important on a local scale, I seriously doubt that their impact needs to be accounted for in global carbon budgets," said Kevin Arrigo, a geophysicist at Stanford University who wasn't involved in the study. 