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Global WarmingNatureScience

Icebergs Are Helping in Previously Unknown Ways

Icebergs have always been majestic objects, and just a little ill-defined, but new research is shedding more and more light on them. In a new discovery that has global implications scientists have discovered that icebergs drifting out to sea leave in their wake an increased level of chlorophyll which in turns increases carbon dioxide absorption.

The research indicates that “iceberg transport and melting have a role in the distribution of phytoplankton in the Weddell Sea,” which was previously unsuspected, said John J. Helly, director of the Laboratory for Environmental and Earth Sciences with the San Diego Supercomputer Center at the University of California, San Diego and Scripps Institution of Oceanography, and who was the lead author of the paper which was originally published in the journal Deep-Sea Research Part II and will soon be republished this month in the journal Nature Geosciences.

The results of the research show that icebergs are especially likely to increase phytoplankton dynamics in an area known as “Iceberg Alley,” east of the Antarctic Peninsula.

On top of this, the team’s research shows that icebergs are likely to become a more common sight in the Southern Ocean as the Antarctic Peninsula disintegrates as a result of the global warming conditions.

But these icebergs will not only be an integral part of the marine ecosystems through which they travel, providing higher levels of nutrients for the sea life and bird life that will follow, but will also be a crucial part of the global carbon cycle.

The researchers studied the effects an iceberg had on its surrounding environment by sampling the area around a large iceberg that measured some 32 kilometres (20 miles) long. The researchers then conducted the same survey ten days later, after the iceberg had moved on its way.

They found that after ten days there were increased concentrations of chlorophyll a and reduced concentrations of carbon dioxide, as compared to the surrounding area, results which are consistent with the growth of phytoplankton and the removal of carbon dioxide from the oceans.

“These new findings amplify the team’s previous discoveries about icebergs and confirm that icebergs contribute yet another, previously unsuspected, dimension of physical and biological complexity to polar ecosystems,” said Roberta L. Marinelli, director of the NSF’s Antarctic Organisms and Ecosystems Program.

The latest findings document a persistent change in physical and biological characteristics of surface waters after the transit of an iceberg, which has important effects on phytoplankton populations, clearly demonstrating “that icebergs influence oceanic surface waters and mixing to greater extents than previously realized,” said Ronald S. Kaufmann, associate professor of marine science and environmental studies at the University of San Diego and one of the authors of the paper.

Check out a Photo Gallery put together by the National Science Foundation of icebergs in Iceberg Alley.

Source: National Science Foundation
Photo Source: Diane Chakros, Scripps Institution of Oceanography/UC San Diego




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