Global climate change is causing Antarctic ice shelves to shrink and split apart, yielding thousands of free-drifting icebergs in the nearby Weddell Sea. According to a new study in this weeks journal Science these floating islands of ice some as large as a dozen miles across are having 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. The researchers discovered that this process produces a halo effect with significantly increased phytoplankton, krill and seabirds out to a radius of more than two miles around the icebergs. They may also play a surprising role in global climate change.
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 oceanographer Ken Smith of the Monterey Bay Aquarium Research Institute (MBARI), first author and principal investigator for the research.
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, added Smith.
To understand the icebergs complex impacts, the multidisciplinary team of researchers carried out the most comprehensive study ever done of individual icebergs and their immediate environment, taking a wide array of measurements physical, biological and chemical, and using satellite images provided by NASA.
At the same time, the wealth of data brought new challenges in how to manage this avalanche of information. The whole is definitely greater than the sum of th
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Contact: Paul Tooby
ptooby@sdsc.edu
858-822-3654
University of California - San Diego
21-Jun-2007