Northernmost lake shows signs of global warming

Researchers from a Quebec university suggested Wednesday that global warming has caused changes in Canada's most northerly lake.

Aquatic life in Ward Hunt Lake located on a small island north of Ellesmere Island in Canada's HighArctic has gone through substantial changesin the past two centuries, Warwick Vincent and Reinhard Pienitz reported.

"The speed and range of these transformations unprecedented in the lakes last 8,000 years suggest that climate change related to human activity could be at the source of this phenomenon," aLaval University release said.

The research suggests the lake was permanently frozen in the past, but changes in the aquatic life "indicate that current conditions make the lake a more favourable location for algae growth than it was in the past," said lead author Dermot Antoniades.

Vincent and Pienitz, from Laval University's Center for Northern Studies, headed a team of international researchers who analyzed an 18-centimetre sediment core taken from the lake in 2003.

Most of the core, dating back 8,450years, had a very small number of algae, but the top two centimetres corresponding to the past 200 years showed "abrupt changes" in the population.

"We cannot claim with certainty that these changes were brought on by human activity, but natural variations observed over the last millennia were never so abrupt and extensive," Antoniades said.

The lake islocated on the 83rd parallel in Quttinirpaaq National Park. The island iscompletely surrounded by ice. Quttinirpaaq means "top of the world" in Inuktitut.

The report will be published in the Sept. 28 edition of Geophysical Research Letters.