The York University Magazine

Fall 2015

The alumni magazine of York University

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Stressed Out? So are Ontario's Lakes F E S P RO F E S S O R Lewis Molot doesn't take the health of Ontario's lakes for granted and neither should we, he says. Molot received his bach- elor's and master's degrees from the University of Toronto and his PhD in oceanography from the University of Alaska in 1981. He has been an FES professor at York for the past 24 years, and during that time, Molot has conducted long-term studies on the effects of eutrophication (enrichment with fertilizers), acidifi- cation, climate change and ultraviolet radiation on lakes in Ontario. His recent research focuses on how ferrous iron and phosphorus promote blooms of nuisance cyanobacteria – a type of algae that is often toxic in fresh waters. Molot is a member of the Provincial Lake Simcoe Science Committee and chair of the Ontario EcoSchools pro- gram, specializing in energy conserva- tion, waste minimization and school yard naturalization in public schools across Ontario. "There are about three million lakes in Canada and about 250,000 of those are in Ontario," says Molot. "Of those, nearly 4,000 in Ontario are greater than three square kilo- metres in area. Most are small and the majority are situated on the Pre- cambrian Shield, which runs in a line from Port Severn on southern Geor- gian Bay to Carleton Place in eastern Ontario, north to the Hudson Bay/ James Bay region." While the majority of Ontario lakes in this region are remote, many also have small populations nearby and are heavily "cottaged." Some may be compromised by nearby resource extraction, including mining and for- estry. But even remoteness does not guarantee lakes are protected from environmental stress caused by either human visitors or airborne deposition of chemicals. Molot cites a number of common threats to water quality of inland lakes, including acid rain, invasive species (introduced by boaters or fishermen), phosphorus enrichment (a byproduct of cottage septic systems and lawn runoff) and climate change, which has shortened the ice-covered season. York has collaborated with scientists at the Ontario government's Dor- set Environmental Science Centre (DESC) on a study of eight small lakes and 20 streams that have now been monitored for more than 30 years. The lakes being studied vary in type, says Molot. "Some have no development, while others have up to 100 cottages with lawns right down to the shoreline – not a good idea, by the way." The good news is that the develop- ment around most lakes in central Ontario has not yet had a negative impact. Molot says that although cottagers' introduction of more phosphorus into lakes has not yet caused problems, there are signs that increasing numbers of lakes are being affected. Phosphorus causes blooms of blue-green algae that can, but do not always, produce liver and nerve tox- ins. "The need for controlled cottage development is still important if we're going to protect water quality and property values." One body of water that has not fared as well as neighbouring smaller lakes is Lake Simcoe. "There are multiple stresses affecting Simcoe," says Molot, citing invasive species (zebra mussels), climate change stressors (such as long- term changes in air temperature and seasonal precipitation patterns) and more urbanization in its watershed. "The annual warming trend near Lake Simcoe has been about 1.5 degrees C in the past 30 years." Luckily, there is now a comprehen- sive long-term plan to protect and restore Lake Simcoe's ecological health. How will other, smaller lakes fare in the long run? "It all depends on the type of lake – for example, deep versus shallow – and the magni- tude of the threat," says Molot. "And there isn't just one threat, there are multiple ones. Our lakes' health is something that has to be managed on all fronts." l Some have no development, while others have up to 100 cottages with lawns right down to the shoreline – not a good idea 32 The York University Magazine Fall 2015 32 The York University Magazine Fall 2015

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