The Arctic Ocean: Awakening | The Economist
Geege Schuman stashed this in Climate Change
Win/win and lose/lose on grand scale.
Let the sun shine in
For living things, this should be excellent news. More open water means more light, which means more photosynthesis. Primary production, as carbon compounds produced by this photosynthesis are known, is rising. Antje Boetius of Bremen University says the seabed at the North Pole is now green—or would be if you could see it—because so much photosynthesis has taken place at the surface and the algae have died and sunk to the bottom. According to Mar Fernández-Méndez of the Alfred Wegener Institute in Bremerhaven, in the summer of 1982 a column of Arctic seawater with a cross-sectional area of a square metre fixed 26 milligrams of carbon a day. By 2012 that figure had risen to 34-53mg.
With rising primary production, and thus more food available, you might expect the rest of the ecosystem to be flourishing, too. And some of it is. There has, for example, been a substantial increase in the number of cod—especially of sexually active cod, more than seven years old. These fish are also now found much closer to the pole than they used to be, at 79° or 80° north. Harbour seals are doing well, too. A colony on Svalbard is the species’s northernmost outpost. Unlike some other seals, harbour seals do not depend on ice to give birth or to moult, so the ice’s retreat is less bothersome to them. And as a predominantly temperate species, they benefit when waters warm up.
Other species, though, are being squeezed by competition from these newcomers and by changing conditions in general. In the waters where cod thrive, minke whales and harp seals are struggling, at least to judge by the condition of their blubber. A study by Bjarte Bogstad of Norway’s Institute of Marine Research found that the blubber of both species had declined from being more than 40mm thick in the early 1990s to less than 35mm now.
The whales may be suffering because the Arctic zooplankton on which they feed are being replaced by more temperate species that are harder to catch or less nutritious. Harp seals suffer directly because they depend on ice (they give birth on it, moult on it and use it for rest while hunting). If the ice is too thin, their pups fall into the water and drown. They also suffer indirectly, through the loss of their main prey, a fish called the capelin, which has begun to swim northward in search of cooler waters. Garry Stenson of Fisheries and Oceans Canada, a government agency, reckons that the number of harp-seal miscarriages has risen greatly in response.
Harp seals exemplify the difficulty of adapting to changing conditions. The obvious response for an ice-dependent animal such as a harp seal would be to follow the retreating ice—in its case, northward from its breeding grounds near Newfoundland. But that would bring the seals closer to their main predator, the polar bear (which eats seal pups). Dr Stenson says harp seals will swim north, but only if there is no ice in March, as happened in 2010. In 2011 there was a little March ice and they stayed put—only to be almost wiped out when the ice melted later in the summer.
Good point that there are many winners and losers.
Things are changing at an alarmingly fast pace.
VICE had an excellent story on the five nations fighting over the $1 trillion in arctic oil:
Why Russia and Canada are clamoring for the Arctic: