Using innovative techniques that enable them to collect historic evidence from fossilized algae in lake bottom sediment, the researchers have found signs of marked environmental changes in a variety of lakes of different depths and composition, within a 750-km region bordering the northern tree-line. The changes are a signal of things to come in the rest of North America, say the Queen's paleolimnologists.
"We're seeing a significant, regional change in the ecology of these lakes over the past two centuries that is consistent with warmer conditions," says Dr. John Smol, Canada Research Chair in Environmental Change and co-head of the university's Paleoecological Environmental Assessment and Research Laboratory (PEARL). Dr. Smol conducted the study with Dr. Kathleen Rhland and student Alisha Priesnitz of Queen's Biology Department.
"Because the Arctic is a very vulnerable environment and usually the first area of the continent to show signs of environmental change often to the greatest degree it's considered a bellwether of what will happen elsewhere," says Dr. Rhland. "These are important signals that all of us should be heeding: the lakes' sedimentary records have tracked marked and directional ecosystem changes."
The Queen's study will be published this month in the international journal Arctic, Antarctic, and Alpine Research.
To reconstruct past environmental trends, the team used fossil markers (tiny algal cells) preserved in lake sediment. Sediment cores were collected by helicopter from the 50 lakes, in an area from Yellowknife, NWT, in the Boreal forest area towards the Bering Sea in the Arctic tundra. For each lake, they compared fossilized algae preserved in the top, most recent sediment layer with those from the bottom, pre-industrial layer dating back about 200 years.
Contact: Nancy Dorrance