Most penguins died after a huge iceberg grounded near their habitat in Antarctica,forcing them to make a long way to find food, scientists say in a newly published study. The B09B iceberg, measuring about 100 square kilometers, 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 decreased to about 10,000, they said. The iceberg's grounding meant the penguins had to walk more than 60 kilometers to find food, preventing their breeding attempts, said the researchers from the University of New South Wales' ( UNSW) Climate Change Research Centre and New Zealand's West Penguin Trust. "The Cape Denison population could disappear completely within 20 years unless B09B relocates or the fast ice within the bay breaks out,"they wrote in the research published in. Fast ice is sea ice which forms and stays along the coast. During their survey in December 2013 , the researchers said "hundreds of abandoned eggs were noted, and the freeze-dried dead bodies of previous season's little penguins lay everywhere on the ground." "It's strangely silent,"UNSW's Chris Turney , who led the 2013 exploration , told the"Sydney Morning Herald Friday"."The ones that we saw at Cape Denison were terribly low-spirited , almost unaware of your existence . The ones that are surviving are clearly struggling. They can hardly survive themselves , let alone give birth to the next generation. We saw lots of dead birds on the ground." In contrast, penguins living on the eastern edge of the bay just 8 kilometers from the fast ice edge were full of _ , the scientists said. The researchers said the study had important influence on the wider East Antarctic if the current situation 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 icebergs to decrease. Scientists believe the growth in Antarctic sea ice is likely to be driven by changes in wind and local conditions before long. What's the main idea of the passage ?
Global warming caused penguins' death. Iceberg harmed penguins' life. Penguins need more habitats. Antarctic extreme weather caused penguins' death.