Huge Antarctic icebergs adrift, could impact ocean circulation
March 4th, 2010 by Jim JustAn article in Pysorg.com reports that a huge iceberg has broken off of Antarctica:
An iceberg the size of Luxembourg knocked loose from the Antarctic continent earlier this month could disrupt the ocean currents driving weather patterns around the globe, researchers said Thursday.
Another iceberg known as B9B, which had been jammed against the Antarctic continent for more than 20 years, began to drift and smashed into the Metz tongue.
I found this satellite picture of the event at the European Space Agency website:
The 2550 square-kilometer (985 square-mile) block broke off on February 12 or 13 from the Mertz Glacier Tongue, a 160-kilometer spit of floating ice protruding into the Southern Ocean from East Antarctica due south of Melbourne. B9B is a remnant of a 2,000-square-mile iceberg that calved in 1987, making it one of the largest icebergs ever recorded in Antarctica.
The resulting new iceberg, along with B9B, have since drifted into an adjoining area called a ploynya – an area that produce dense water, super cold and rich in salt, that sinks to the bottom of the sea and drives the conveyor-belt like circulation around the globe. The Metz Glacier Polynya is particularly strong and accounts for 20 percent of the “bottom water” in the world.
Benoit Legresy, a French glaciologist who works at the Laboratory for Geophysics and Oceanographic Space Research in Toulouse and who has been monitoring the Metz glacier, explains how the icebergs could possibly disrupt ocean circulation patterns:
[I]f they stay in this area – which is likely – they could block the production of this dense water, essentially putting a lid on the polynya.