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.