Some 150,000 penguins died after a massive iceberg grounded
near their colony in Antarctica, forcing them to make a lengthy
trek to find food, scientists say in a newly published study.
The B09B iceberg, measuring some 100 sq km, grounded in
Commonwealth Bay in East Antarctica in December 2010, the
researchers from Australia and New Zealand wrote in the Antarctic
Science journal.
The Adelie penguin population at the bay's Cape Denison was
measured to be about 160,000 in February 2011, but by December 2013
it had plunged to an estimated 10,000, they said.
The iceberg's grounding meant the penguins had to walk more than
60km to find food, impeding their breeding attempts, said the
researchers from the University of New South Wales' (UNSW) Climate
Change Research Centre and New Zealand's West Coast Penguin
Trust.
"The Cape Denison population could be extirpated within 20 years
unless B09B relocates or the now perennial fast ice within the bay
breaks out," they wrote in the research published in February.
Fast ice is sea ice which forms and stays fast along the coast.
During their census in December 2013, the researchers said
"hundreds of abandoned eggs were noted, and the ground was littered
with the freeze-dried carcasses of previous season's chicks".
"It's eerily silent now," UNSW's Chris Turney, who led the 2013
expedition, told the Sydney Morning Herald on Friday.
"The ones that we saw at Cape Denison were incredibly docile,
lethargic, almost unaware of your existence.
"The ones that are surviving are clearly struggling. They can
barely survive themselves, let alone hatch the next generation. We
saw lots of dead birds on the ground... it's just heartbreaking to
see."
In contrast, penguins living on the eastern fringe of the bay, just
8km from the fast ice edge were thriving, the scientists said.
The researchers said the study had "important implications" for the
wider East Antarctic if the current trend of increasing sea ice
continued.
Sea ice around Antarctica is increasing, in contrast to the Arctic
where global warming is causing ice to melt and glaciers to
shrink.
Scientists believe the growth in Antarctic sea ice is largely
driven by changes in wind and local conditions.
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