Five meters of ice - about 16 feet thick - is threatening the survival of polar bears in the Southern Beaufort Sea region along Alaska's Arctic coast, according to Dr. Susan J. Crockford, an evolutionary biologist in British Columbia who has studied polar bears for most of her 35-year career.
Female polar bear with cubs.
That's because the thick ice ridges could prevent ringed seals, the bears' major prey, from creating breathing holes they need to survive in the frigid waters, Crockford told CNSNews.com.
"Prompted by reports of the heaviest sea ice conditions on the East Coast 'in decades' and news that ice on the Great Lakes is, for mid-April, the worst it's been since records began, I took a close look at the ice thickness charts for the Arctic," Crockford noted in her Polar Bear Science blog on April 18th.
"Sea ice charts aren't a guarantee that this heavy spring ice phenomenon is developing in the Beaufort, but they could be a warning," she wrote, noting that they "don't bode well" for the Beaufort bears.
"What happens is that really thick ice moves in because currents and winds from Greenland and the Canadian islands push it against the shore," Crockford told CNSNews.com.
Comment:
I've run into holes like these while hiking across the Oregon Dunes. One explanation for the holes is that ancient trees that were buried by the sand that decomposed sometimes leave these deep, narrow holes and the holes can persist, under a layer of sand for a very, very long time. I stepped onto such a patch of sand and the sand gave way and I was suddenly in sand up over my knee. When I pulled my foot out and looked down the hole I could not see the bottom. I think I joked to my hiking partner about the holes being created by baby sandworms (the author of Dune, Frank Herbert, said he came up with the original idea for the novel while hiking in the Oregon dunes.) I actually found a reference in another locally-inspired novel that might have even specifically referred to one kind of dune tree hole:
In Sometimes a Great Notion, Ken Kesey's fictional novel about a rough logging town on the Oregon coast, a character walking in the dunes at night plummets into the shaft of a buried hollow tree - called a devil's stovepipe.
About "tree holes" in the dunes
About the Oregon Dunes & Frank Herbert connection