How is climate change affecting fauna in the Arctic?

“Our hypothesis is that the low-hanging clouds typically found in the Arctic are to a large part responsible for the fact that, over the past few decades, the region has warmed at more than twice the speed of the rest of the planet. This phenomenon is commonly referred to as ‘Arctic amplification’ and hasn’t yet been reflected in global climate models, because we still don’t sufficiently understand the mechanisms involved,” explains Prof Andreas Macke from the Leibniz Institute for Tropospheric Research (TROPOS), who will serve as Chief Scientist for the first leg of the expedition. His project is intended to help us understand in detail which processes are making the sea ice vanish so dramatically in the Arctic, and to what extent. In this regard, the atmospheric measurements taken on board RV Polarstern will be supplemented by a weather balloon tethered to the ice floe, the flights of the AWI research aircraft Polar 5 and Polar 6, and parallel measurements taken at the AWIPEV Station in Ny-Ålesund, so as to arrive at as complete a picture of atmospheric processes in the Arctic – which ultimately also influence the weather in Europe – as possible. 

“We’re especially interested in the polar cod, which, as the primary food source for seals and birds, plays a key part in the Arctic ecosystem,” says Dr Hauke Flores. The biologist from the Alfred Wegener Institute will join the expedition in Bremerhaven and, following a brief stop in Longyearbyen (Svalbard) on 21 June, will take over the reins for its second leg. Young polar cod tend to frequent the underside of sea ice, which simultaneously serves as a hunting ground and offers them protection from predators. As a result of climate change, the spatial extent of this under-ice habitat is shrinking rapidly. “We will simultaneously investigate the polar cod’s spatial distribution, primary food sources, predators that feed on it, and other environmental parameters. This will allow us to assess the survivability of the cod, and of the endotherms that depend on it, and to make informed statements on their sensitivity to climate change,” relates Flores. Looking ahead to the two months before the expedition’s end (in Tromsø, Norway in mid-July), he enthuses, “In addition to the latest observations, I’m especially excited about the talks with fellow researchers from a range of disciplines; while on board, we’ll have an unparalleled opportunity to exchange notes on our research interests for an extended period.”

Following the expedition, AWI deep-sea researchers and their colleagues will use RV Polarstern for long-term biological and oceanographic investigations in the AWI’s “Hausgarten” deep-sea observatory. In August and September, members of the Helmholtz Alliance ROBEX will travel to the Fram Strait between Greenland and Svalbard, where they will e.g. retrieve the deep-sea robot Tramper, which just completed a year of operations in the Arctic. The destination of this year’s last expedition to the Arctic, beginning in mid-September, will be eastern Greenland, where oceanographers and glaciologists will join forces to get to the bottom of the mechanisms involved in melting glaciers. The research vessel Polarstern is scheduled to return to its home port, Bremerhaven, in mid-October.