Antarctic melting affecting distant seabirds
Antarctica’s rapidly shrinking sea ice is making it more difficult for seabirds that breed hundreds of miles away to find food, a study published in Progress in Oceanography suggests.
Antarctica is a remote and dynamic place. Vast swathes of sea ice form around it in winter and then melt in summer, releasing concentrated nutrients into the ocean. Hundreds of miles away, albatrosses and large petrels breed on the islands that surround Antarctica.
Researchers from Durham University and the British Antarctic Survey used satellite technology to track the foraging trips of seven species of albatross and petrel, breeding on South Georgia. They recorded 2,497 trips made by 1,289 birds between 1992 and 2023 and found that all of the species visited Antarctica.
In spring, for example, southern giant petrels flew hundreds of miles into the pack ice, where researchers think they were landing to scavenge on seals. Meanwhile, albatrosses largely avoided the ice-covered areas, but in late summer and autumn, fed in the open water areas where the ice had melted.
“Given that all seven species of albatross and petrel we looked at travelled to the Antarctic seasonal sea ice zone, it is likely that they, and many other sub-Antarctic breeding seabirds, are linked to sea ice dynamics,” says Richard Phillips from the British Antarctic Survey. “Declines in Antarctic sea ice predicted under climate change could exacerbate the already unsustainable human impacts being experienced by these populations.”
Until recently, Antarctica had not suffered the big losses of sea ice seen in the Arctic, but now climate change is causing the seasonal melt to start earlier and the ice to recede more quickly. The concern is that this will force the seabirds to travel further from their breeding grounds to find food for their chicks, or that it could alter the patterns of where that food is found. In turn, this could affect the ecosystems that these birds are a part of.
Holding up to three quarters of the world’s breeding populations of seven species of albatrosses and petrels, South Georgia is an important stronghold for these birds.
“Antarctica’s receding sea ice, driven by climate change, could affect not just the penguins, familiar to many people, that breed on the continent, but also huge numbers of seabirds breeding hundreds or thousands of miles away,” says Ewan Wakefield from Durham University.