National Geographic : 2014 Aug
108 national geographic • August 2014 copepod communities change because of cli- mate change in the Arctic, the little auks will show a strong response.” How might the copepod fauna change? One of the larger and fatter kinds, Calanus glacialis, depends upon very cold water and the presence of sea ice, beneath which grow the algae that it eats. A smaller and leaner species, Calanus fin- marchicus, is common in the North Atlantic and often rides currents into the Arctic but doesn’t flourish there. As the Arctic Ocean warms by a few degrees, though, the competitive balance could shift. Higher temperatures and decreases in sea ice could allow the small, lean copepods to replace the big, fat ones, to the detriment of the little auk—and of other creatures as well. Arctic cod, herring, and various seabirds feed on the copepods, and even such mammals as ringed seals and beluga whales depend on fish that feed on them. That’s why scientists consider Calanus glacialis a keystone species in the Arctic. Grémillet and Fort catch little auks by lay- ing out patches of “noose carpet” in which the birds get their feet tangled, and then each bird is weighed, measured, and banded. Some birds are also fitted with a time-depth recorder or a geolocator, miniaturized units affixed to a leg or to breast feathers, from which data can be retrieved. The geolocators will track migration routes south after the birds have bred. The time- depth recorders will reveal how deep a bird has dived, how long it has stayed down on each dive, and how many hours daily it has devoted to such laborious food getting. From earlier work on Greenland and Spitsbergen, Grémillet and Fort know that during winter little auks that have only Calanus finmarchicus to eat must forage up to ten hours a day to meet their energy needs. How much worse might it be if in summer, with chicks to feed and incubate, they have only that labor-intensive source of food? So far little auks have shown admirable flex- ibility in the face of incremental change. But the question is, Fort says, how much further can they flex? “We think there will be a breaking point.” On a Monday in late August, after two tries, we succeed in reaching Cape Fligely, on the north coast of Rudolf Island, the most northern of the group. Here, while the others are variously focused, Paul Rose and I escape ashore for a hike to the top of the glacier. We climb up from the beach cautiously, because two polar bears showed themselves hereabouts last night and one again this morn- ing. But those animals seem to have ambled away, and the coast is clear. As always, we have a security man: another young Russian, Alex- ey Kabanihin, who carries flares, a radio, and a Saiga-12, its clip loaded with blank rounds preceding the real ones. It’s a glorious sunny day. From the western cape where we’ve landed, a great dome of ice rises gently inland and up- ward, a smooth arc sweeping toward nothingness like the curvature of the moon. Far below, afloat This Pristine Seas Expedition was generously supported in part by Blancpain, Davidoff Cool Water, and your National Geographic Society membership. One bear strides toward us. Suddenly I feel as if we’re just three pieces of dark meat on a very white plate.