Quebec City, September 26, 2007Analyses conducted by researchers from Universit Lavals Center for Northern Studies reveal that the continents northernmost lake is affected by climate change. In an article to be published in the September 28 edition of Geophysical Research Letters, the international research team led by Universit Laval scientists Warwick Vincent and Reinhard Pienitz reports that aquatic life in Ward Hunt Lake, a body of water located on a small island north of Ellesmere Island in the Canadian Arctic, has undergone major transformations within the last two centuries. The speed and range of these transformationsunprecedented in the lakes last 8,000 yearssuggest that climate change related to human activity could be at the source of this phenomenon.
The researchers conclusions are based on the analysis of a sediment core extracted in the center of Ward Hunt Lake in August 2003. This 18 centimeter long sediment core containing algae pigments and diatom remnants was used by the researchers as a biological archive in order to determine the diversity and abundance of aquatic life-forms in the lake over the last 8,450 years.
Analysis of the deepest layers of sediment revealed a very small number of algae as well as only minor variations in concentration. However, the top two centimeters of the core, which correspond to the last 200 years, showed abrupt changes in the lakes algae population: during that period, chlorophyll a concentration, a pigment found in every species in the lake, increased by a factor of 500. A type of diatom typical of very cold environments also made its first appearance during the same period. The absence of diatoms and the low pigment concentration below the top 2.5 centimeters of the core suggest that the lake was permanently frozen in the past, explains lead author and Center for Northern Studies researcher Dermot Antoniades.
Located on the 83rd parallel in the Quttinirpaaq (meaning top of the world
|Contact: Jean-Franois Hupp|