Arctic Ice March 2011 Update #2


The melt season of 2010 ended with a low extent and with little ice older than two years. There are strong indications that the winter of 2010 - 2011 did not compact and thicken the sea ice as much as would normally be expected.

Arctic sea ice extent averaged over December 2010 was 12.00 million square kilometers (4.63 million square miles). This is the lowest December ice extent recorded in satellite observations from 1979 to 2010, 270,000 square kilometers (104,000 square miles) below the previous record low of 12.27 million square kilometers (4.74 million square miles) set in 2006 and 1.35 million square kilometers (521,000 square miles) below the 1979 to 2000 average.
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Researchers have discovered a 525-million-year-old fossil which belongs to a group of tentacle-bearing creatures which lived inside hard tubes. 

The creature belongs to a group called pterobranch hemichordates which are related to starfish and sea urchins but also show some characteristics that offer clues to the evolution of the earliest vertebrates. About 30 species of pterobranch are known to exist today although 380-490 million years ago a group of these animals called graptolites were common across the prehistoric oceans.