Ancient whalers altered arctic lakes

Analyses of sediment and water from an arctic lake indicate that an ancient whaling community left a mark on the lake’s ecosystem that persists today, even though the settlement was abandoned centuries ago.

LAKE HOUSE. Canadian guide stands amid the remains of a whalebone hut whose decomposition is affecting water chemistry in a nearby lake. PNAS

Thule Inuit whalers moved from Alaska to islands in the Canadian Arctic about 1,000 years ago. Their former settlements are easily spotted because whale bones still litter the landscape, says paleoecologist John P. Smol of Queen’s University in Kingston, Ontario.

One site near a freshwater pond on Canada’s Somerset Island includes 11 huts that had been constructed from whale bones and is surrounded by the remains of 125 bowhead whales and several hundred seals, says Smol. Phosphorus and other nutrients released by the decomposing bones fertilize adjacent clumps of vegetation and leach into the pond. In 1995, the concentration of phosphorus in the pond ranged from 2 to 15 times the concentrations found in 10 nearby lakes that didn’t have whale remains nearby, Smol and his colleagues report in the Feb. 10 Proceedings of the National Academy of Sciences.

Layers of sediment deposited in the pond about 800 years ago show an elevated concentration of nitrogen-15. That isotope, which appears in higher proportions within marine organisms than in the environment, came from decaying whales and heralded the founding of the Inuit community, says Smol.

Unlike the persistent changes in water chemistry, algae content of the lakes has almost reverted to a presettlement condition. According to the sediment analyses, species of algae deposited in lake silt during the past 400 years are similar to those from sediments laid down before settlers arrived. That, says Smol, suggests that the site was abandoned by the whalers around A.D. 1600.

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