Nov. 14, 2000 -- A U of T researcher has found a polar lake in the Arctic to have significantly recovered despite decades of sewage dumping, proving that if given a chance, nature can help people clean up their act.
Marianne Douglas, a geology professor, and her co-investigator, Queen's University professor John Smol, analyzed clusters of algae or diatoms and water samples taken from Meretta Lake at Resolute Bay, Nunavut, to determine the lake's water quality. "We were pleased to see the quickness of the lake's recovery and found the use of the diatoms to be very effective bio-monitors of the lake's conditions," she says. From 1949 to 1998, a Canadian Department of Transport base and other facilities dumped sewage into the lake. At its peak in the early 1970s, the base supported a population of approximately 200 but has declined to 65 today. No waste has been dumped in the lake since 1998.
The researchers took water samples from Meretta Lake and three ponds that feed into it to examine the phosphorus levels - a component of raw sewage and a nutrient that spurs algae growth - and compared their results with data from an earlier 1970s study done during the peak of activity at the base. They found that the phosphorus levels have declined sharply since 1972, which is in keeping with the decreased population of the military base. They also noted that certain species of algae thrived when there were high concentrations of phosphorus in the lake due to sewage dumping.
The researchers examined sediment from the lake for different species of algae or diatoms to get a snapshot of the lake's contamination levels at different time periods. These diatoms tracked the increase in nutrient levels accurately and can be used as effective paleoecological tools in future research. "We are eager to test the method on sites where archeologists suspect past communities of northern peoples camped 1,000 years ago," says Douglas. "Diatoms will be important indicators in tracking these past populations."
The study was supported by the Natural Sciences and Engineering Research Council of Canada and the Polar Continental Shelf Project and was recently published in Hydrobiologia.
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