Alaska’s living reefs – which house an entire ecosystem – are collapsing thanks to climate change and the disappearance of sea otters, new research published in the journal Science reveals.
Weakened by warming waters and increased acidity, the centuries-old reefs are being ground down by sea urchins, whose population has exploded following the functional extinction of their predator, the Aleutian sea otter.
“It’s basically a top down relationship,” says Jochen Halfar, a paleoclimate and paleontology professor at the University of Toronto Mississauga who studies sea floor algae and was one of the study’s authors.
He says that, with the loss of their original food source due to hunting, orcas now prey on sea otters, seals and other smaller marine animals. The adaptation has, in turn, led to the removal of sea otters from the system and their main food source – sea urchins – are now proliferating unchecked.
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Image via J. Tomoleon.