Iceberg ecosystems may help ease global warming

Tuesday, October 23, 2007 by: David Gutierrez, staff writer
Tags: climate change, health news, Natural News

(NewsTarget) Antarctic icebergs create miniature marine ecosystems that allow more life than normally exists in an otherwise nutrient-poor region, according to a study published in the journal Science.

Researchers used underwater cameras to observe the undersides of two gigantic icebergs in the Wendell Sea. The icebergs were nearly 12.5 miles long and more than 130 feet tall, with one of them extending almost 1,000 feet beneath the water. The researchers found that the icebergs attracted huge colonies of sea birds above the surface and increased the concentrations of algae, phytoplankton, krill and fish below, thus increasing the biological productivity of the sea by nearly 40 percent.

The number of icebergs in the Antarctic Ocean has been increasing in recent years, as its ice sheets have begun to break up due to global warming. However, the authors of the study speculate that the increased carbon sequestration caused by the icebergs may slow, in some way, the progress of global warming.

The marine ecosystem created by the iceberg is favorable to algae and phytoplankton, which pull carbon dioxide from the atmosphere and shift it into the food chain. "While the melting of Antarctic ice shelves is contributing to rising sea levels and other climate change dynamics in complex ways, this additional role of removing carbon from the atmosphere may have implications for global climate models that need to be further studied," said Ken Smith, an oceanographer at the Monterey Bay Aquarium Research Institute in California.

However, the biological effects of the iceberg may not be permanent. The researchers believe that the icebergs increase the density of life beneath and around them -- for up to a 2-mile radius -- by shedding accumulated terrestrial nutrients, particularly iron, into the ocean.

"The Southern Ocean lacks a major source for terrestrial material due to the absence of major rivers," said Timothy Shaw, a geo-chemist at the University of South Carolina. "The icebergs constitute a moving estuary, distributing terrestrial derived nutrients that are typically supplied by rivers in other areas of the oceans."

How long this nutrient source will last as the icebergs continue to melt is unknown.