PENGUINS in the Antarctic are facing starvation because two giant icebergs
have blocked their path to and from the sea.
Researchers at McMurdo Station near the Ross Sea say a number of colonies are
on the brink of collapse as female birds are marooned at sea and their mates
abandon nests. The researchers don鈥檛 know whether global climate change is to
blame.
After female Ad茅lie and emperor penguins lay their eggs, they normally
spend several days hunting in the open sea before returning to their breeding
grounds. But the icebergs known as B15 and C16, which broke away from the Ross
Ice Shelf in 2000, are now lodged against the ice that covers the Ross Sea and
are blocking their way.
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鈥淲e think a large number [of female penguins] became bewildered after
diverting their route way around B15 to then find C16 in their path, so they
gave up,鈥� penguin specialist David Ainley told 快猫短视频 in an
e-mail from McMurdo Station. Their mates left behind incubating the eggs waited
weeks until hunger drove them to desert the nests.
A massive stretch of ice covering the Ross Sea has also forced the penguins
to attempt a 75-kilometre waddle to the colonies. At its peak this year, the ice
sheet was four times as extensive as normal, possibly because the icebergs
blocked the winds that usually melt it, says Doug MacAyeal, a glaciologist at
the University of Chicago. The year 2000 saw the calving, or splitting off, of
huge numbers of particularly large icebergs. These icebergs only calve every 50
years on average, 鈥渟o we don鈥檛 know if they are related to global warming,鈥�
MacAyeal says.
But David Vaughan of the British Antarctic Survey thinks that global climate
change could be playing a role in the penguins鈥� plight, and that it could force
the birds to move. 鈥淭here are other areas of Antarctica where penguins changed
their breeding sites in response to an increase in temperature.鈥�
The Ross Ice Shelf lies at the edge of the West Antarctic Ice Sheet, which
overlies the Antarctic continent. In a recent survey, only 5 per cent of
scientists thought the ice sheet would melt significantly over the next 200
years.