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Icebergs
have long gripped the popular imagination, whether as
relatively run-of-the-mill floating hazards that cause
"unsinkable' ships to founder or, more recently,
as enormous breakaway pieces of ice the size of states
or small countries.
But, according to a paper published in this week's Science
magazine, scientists have discovered that these floating
ice islands--some as large as a dozen miles across--have
a major impact on the ecology of the ocean around them,
serving as "hotspots" for ocean life, with thriving
communities of seabirds above and a web of phytoplankton,
krill and fish below.
The icebergs hold trapped terrestrial material, which
they release far out at sea as they melt. Scientists have
discovered that this process produces a "halo effect"
with significantly increased nutrients, chlorophyll and
krill out to a radius of more than 3 kilometers (2 miles).
Based on their new understanding of the role of icebergs
in the ecosystem and the sheer number of icebergs in the
Southern Ocean--the researchers counted more than 11,000
in satellite images of some 4,300 square miles of ocean--the
scientists estimate that, overall, the icebergs are raising
the biological productivity of nearly 40 percent of Antarctica's
Weddell Sea.
Scientists also have begun to suspect, but argue for
additional study, that icebergs may also play a surprising
role in global climate regulation by removing carbon from
the atmosphere.
The National Science Foundation (NSF) funded research
was conducted by scientists from the Monterey Bay Aquarium
Research Institute, the San Diego Supercomputer Center,
Scripps Institution of Oceanography, the University of
San Diego and the University of South Carolina.
As manager of the U.S. Antarctic Program, NSF coordinates
and provides logistical support to all U.S. research conducted
on the southernmost continent. The White House Office
of Science and Technology Policy has designated NSF as
the lead agency for the International Polar Year, a global
scientific deployment to the Polar Regions that began
in March 2007.
NSF officials agreed that the new research may open a
new and productive field for ecosystem research at the
dawn of the Polar Year.
"This research establishes yet another promising
horizon for polar ecology," said Roberta Marinelli,
organisms and ecosystems program director for the U.S.
Antarctic Program. "And as we progress through the
International Polar Year, NSF hopes to expand this work
to learn yet more about these unique ecological niches
and their significance to oceanic processes."
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NSF.gov-
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