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.”

From the NSF Antarctica website.

Antarctica by the Numbers: Antarctica once was part of an enormous and temperate supercontinent called Gondwanaland. It broke free of its connection to other landmasses millions of years ago and began its southward drift. Today, it is a continent of extremes. For example:

* The continental landmass is 5.4 million square miles, an area larger than the U.S. and Mexico combined.
* More than 98 percent of the landmass is covered by an ice sheet that has accumulated over millions of years. The ice sheet averages just over 7,000 feet thick, but is more than twice that thick in places.
* Antarctica holds 90 percent of the world’s ice, which in turn represents 70 percent of the world’s fresh water. Yet precipitation in the interior averages only a few inches annually, making Antarctica one of the world’s great deserts.
* The ice sheet at the South Pole is in constant motion, moving about 30 feet every year and necessitating an annual remarking of the geographic South Pole.
* As the ice moves out toward the edge of the continent, it breaks off, “calving” the world’s largest icebergs, including one that was estimated to be similar in area to the state of Delaware.
* In the unlikely event that the Antarctic ice sheet melted suddenly, it would raise sea levels worldwide an estimated 200 feet, submersing much of the Gulf and Atlantic coastal areas of the U.S.
* Winds blowing from the interior plateau often reach speeds of 80 mph at the coast and can peak at 180 mph.
* The lowest surface temperature ever recorded on Earth was – 128.6 degrees Fahrenheit at Russia’s Vostok Station in the continent’s interior.