Sunday, June 24, 2007
Melting Icebergs are Party Central for Ocean Life
Icebergs are breaking from Antarctica at an ever increasing rate, and every day there are new images and startling revelations about the loss of habitat for our South Pole flora and fauna. But what happens to the ice when it breaks away and floats to the ocean? Scientists from the Monterey Bay Research Center set out to find out what effect these frozen travellers have on the waters they occupy.
Anecdotal reports suggested an increase in seabird activity around these icebergs, but no one knew just why. It turns out that these melting ice masses are carrying organic and mineral debris stored from millennia, and releasing them into the cold waters off South America. These ocean waters are normally low in essential nutrients, like iron. As the icebergs melt, they act as a timed release fertilizer, increasing ocean life around them, such as algae. Organisms that take particular delight in the new food source are krill, the tiny shrimplike creatures that occupy the bottom of the food chain for marine mammals, even providing a direct source for many whales. When an iceberg breaks off and drifts, it creates a new habitat for opportunists, and increases biodiversity for a distance of up to 2 1/2 miles from the edge of the drift.
Not only is the afterlife of an iceberg spectacular, but this new life in turn is able to absorb enormous amounts of the CO2 that created the melting in the first place, in a sort of feedback loop. "One important consequence of the increased biological productivity is that free-floating icebergs can serve as a route for carbon dioxide drawdown and sequestration of particulate carbon as it sinks into the deep sea," said project leader Kenneth Smith Jr. "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."
Is this the silver lining? We'll have to find out.
for the article at ENN
for the scoop on Antarctica, including stories abut its natural and human history