But some critics are challenging that assertion, pointing out that the penguins may have just migrated to happier hunting grounds. “More than 150,000 Adelie penguins have perished in a single colony in Antarctica after the grounding of a giant iceberg” five years ago, Turney and fellow researchers from UNSW’s Climate Change Research Centre and New Zealand’s West Coast Penguin Trust wrote in an article published this month in the British peer-reviewed journal Antarctic Science.
Turney was the leader of the Australasian Antarctic Expedition 2013-2014 that went to Antarctica to update the scientific records compiled a century ago by Sir Douglas Mawson, including a census of the penguin population at Cape Denison. Turney said that gathering the new data was critical because it would allow climate scientists to document the effects of global warming on Antarctica.
The expedition’s Russian ship - with dozens of climate scientists aboard – had to be rescued after it got stuck in ice for 10 days. The B09B iceberg, which broke off of the Ross Ice Shelf in 1987, ran aground off Cape Denison in Antarctica’s Commonwealth Bay in 2010, filling the bay with ice and blocking the penguins’ access to the open sea. "The arrival of iceberg B09B in Commonwealth Bay, East Antarctica, and subsequent fast ice expansion has dramatically increased the distance Adelie penguins (Pygoscelis adeliae) breeding at Cape Denision must travel in search of food," according to the study. "Whilst some 5,520 pairs still breed at Cape Denison, there has been an order of magnitude decline in Adelie numbers in the area in comparison to the first counts a century ago and, critically, recent estimates based on satellite images and a census in 1997."
However, the study acknowledged that “abandoned Adelie penguin colony sites are common,” and stated that another penguin colony located about five miles away was “thriving”.
Kerry-Jane Wilson, the study’s lead author, did not respond to an email from CNSNews.com, asking her: “How do you know that that the 150,000 Adelie penguins missing from Cape Denison died? Isn't it possible that some or even most of them left the area and migrated to areas along the coast where they had access to food?”
Turney’s claim that the iceberg caused the deaths of 150,000 penguins in the Cape Denison colony was challenged by LiveScience’s Becky Oskin. "Let's give the penguins a little credit," she wrote in a Feb. 16 article in Discovery. "There's no proof yet that the birds are dead. No one has actually found 150,000 frozen penguins."
Oskin quoted Michelle LaRue, a penguin population expert at the University of Minnesota, who said that "just becasue there are a lot fewer birds observed doesn't automatically mean the ones that were there before have perished. They easily could have moved elsewhere, which would make sense if nearby colonies are thriving.”
In a 2013 study of Adelie penguins on Beaufort Island in Antarctica’s Ross Sea, LaRue and her colleagues found that penguins appeared to benefit from climate change because their numbers had increased 84 percent over the previous five decades.