A new study published in Science finds another downside to sea ice melt for polar bears.
Scientists found that polar bears not only need sea ice as a platform for hunting seals, but also to grow the food that the seals’ prey eats—and that food is now going somewhere else. A series of chain reactions starts with abundant algae and ends with fewer polar bears.
Sea ice in the Arctic Ocean thinned and shrank to a record low in September 2012. The thinner ice allowed more sunlight to get through and feed algae that grows on the underside of the ice. As the ice melted, the algae sunk to the ocean floor and was eaten by brittle stars and sea cucumbers, instead of by fish closer to the ocean’s surface.
"For surface life it could be bad news, for the deep sea floor it could be a feast," said Antje Boetius, of the Alfred Wegener Institute for Polar and Marine Research in Germany and lead author of the study.
Surface life, such as ringed seals, depend on the algae-eating fish that are now going hungry. And polar bears need seals to survive.