25 May 2012
Life in Wascana Lake: Aquatic ecosystem studies
I had the chance to learn more about Regina's man-made Wascana Lake recently in a new speaker's night at the Saskatchewan Science Centre.
One of the speakers was Dr. Richard Vogt. He has a postdoctoral fellowship in biology at the University of Regina to study structure and functioning of aquatic communities and ecosystems. He works with Dr. Peter Leavitt in the Limnology Lab, using the long-term database of lakes in the Qu'Appelle River catchment to explore important questions in limnology (meaning the study of freshwater lakes and marshes) and aquatic ecology.
Limnology lab scientists monitor Wascana Lake as one of six major lakes in the Qu'Appelle Valley wastershed, Vogt told about 30 people who came to hear three speakers on water issues on May 4, to open the exhibit "Water's Extreme Journey." Vogt grew up in Ontario and took his PhD in Aquatic Community Ecolology from the University of Quebec in Montreal. He said his colleagues would envy the U of R for its “rare and valuable” database of samples, collected every two weeks – in all seasons – for some 16 years.
Part of Vogt's studies with Leavitt include the effect of Regina’s “Big Dig” in 2004. During the $18-million Wascana Lake Revitalization Project, or “Big Dig" as it's known locally, Wascana was dredged from about 1.5 metres to about five metres in depth, removing over 1.3 million cubic metres of soil in about four months. (More on the dig can be found in The Big Dig: The Miracle of Wascana Centre by Bob Hughes.)
Vogt's studies show that surprisingly, the project hasn’t affected Wascana Lake the way scientists predicted it would. For example, scientists predicted the dredging would make the lake less clear and cause an increase in algae. Up to then, he said, rooted plants locked up the nutrients in the lake sediments, providing a habitat for zooplankton that graze on algae. Plants growing all the way to the water’s surface would get caught in people’s boat oars, and have to be mulched periodically.
But the dredging caused “no change in the most important water quality indicators” in the lake, Vogt said. Although the overall number of plants was reduced, there has been no increase in algae, and no decrease in clarity. There are some differences in algae species that thrive in the lake, but “for the most part we see a similar diversity,” he added.
For more information, check http://www.uregina.ca/biology/faculty/Leavitt/labsite_files/wascana.html
Marie Powell is the author of Dragonflies are Amazing! (Scholastic Canada, Grade Two Guided Reading, 2007). (Note: A version of this material appears in Marie's article in Metro Regina print edition, May 10 2012. Photo: Wascana Lights by L L Melton.)