Elephant seals help ice study
2008-08-13 17:17
Sydney - Elephant seals swimming
under Antarctic ice and fitted with special sensors are
providing scientists with crucial data on ice formation, ocean
currents and climate change, a study released on Tuesday said.
The seals swimming under winter sea ice have overcome a
"blind-spot" for scientists by allowing them to calculate how
fast sea ice forms during winter.
Less ice, more warming
Sea ice reflects sunlight back into space, so less sea ice
means more energy is absorbed by the earth, causing more
warming.
"They have made it possible for us to observe large areas
of the ocean under the sea ice in winter for the first time,"
said co-author Steve Rintoul from Australia's Commonwealth
Scientific and Industrial Research Organisation (CSIRO).
The elephant seals have provided scientists with a 30-fold
increase in data recorded in parts of the Southern Ocean, said
the study by a team of French, Australian, US and British
scientists and published in the Proceedings of the National
Academy of Sciences.
Between 2004 and 2005, the seals swam up to 65km
a day, supplying scientists with 16 500 ice
profiles. The seals dived to a depth of more than 500m
on average and to a maximum depth of nearly 2km.
"If we want to understand what's going to happen to climate
in the future we need to know what the sea ice is going to do.
"Will there be more or less and will it form more or less
rapidly?" Rintoul told Australian Broadcasting Corporation radio.
The experiment involved 85 seals with sensors attached to
their heads.
Polar regions' important role
The polar regions play an important role in the earth's
climate and are changing more rapidly than any other part of
the world, with the Southern Ocean warming more rapidly than
the global ocean average.
Sea ice not only affects the amount of energy reflected
back into space but also the amount of dense water around the
Antarctic which drives ocean currents that transports heat
around the globe.
Sea ice also provides a critical habitat for krill,
penguins and seals.