RESEARCH
Our group performs research in the area of environmental toxicology. We investigate how chemicals released into the environment affect terrestrial and aquatic ecosystems. This involves investigations at a wide range of biological levels of organization, e.g., metabolites within an organism and all the way to biological communities within an ecosystem.
Left: Earthworm (Eisenia fetida) in the inner chamber of test units used in avoidance tests. The worm can select from six chambers containing soil. Three of the chambers contain clean soil and three chambers contain soil that has been spiked with a contaminant. Replicate chambers at different concentrations of contaminants are used to determine at what concentrations will the worms actively avoid the contaminated soil.
Right: A three-dimensional image of a worm that has ingested polyethylene microplastics coated with barium sulphate (22 to 46 µm). The image was created using X-ray microtomography at the Canadian Light Source facility in Saskatoon, Saskatchewan. The image allows us to determine whether the microplastics will move across the lining of the gut into other tissues of the worm.
Left: It may resemble a planet, but this wood frog (Lithobates sylvaticus) embryo is only a few millimeters across. Cell division is occurring rapidly, but rather than the embryo growing larger, the cells get smaller with each division. This embryo will be used to ascertain the health effects of pollution on its species.
Right: Wood frog hatchling (~3.5 weeks post-fertilization) at Gosner developmental stage 24. You can see blood circulating through the exposed gills, which will soon be covered and protected by the operculum.
Left: Mating pair of American toads (Anaxyrus americanus) in Lake 239 at the Experiment Lakes Area in Northern Ontario
Right: Giant floater mussel (Pyganadon grandis) in Lake 375 at the Experimental Lakes Area in Northern Ontario
Left: Embryos of the freshwater pulsate snail Planorbella pilsbryi. Our group has been developing a toxicity tests that use snail embryos to assess the toxicity of chemicals or water samples collected from the field.
Right: The larvae of the mayfly Neocloeon triangulifer. This mayfly species allow us to investigate the effect of chemicals on the aquatic insects throughout the entire life cycle. This is challenging because the life cycle of many mayfly species are 1 year or longer. The length of the life cycle of Neocloeon triangulifer is 30 days.
Left: Female wavyrayed lampmussels (Lampsilis fasciola) using a lure display to attract a fish host for their larvae (glochidia). Baby mussels spend the first weeks of their life on the gill or fin of a fish host going through metamorphosis. These beauties were found in a tributary of the Grand River in Ontario, Canada.
Right: Various freshwater mussel species collected during a survey of a site in the Grand River, Ontario. All of these mussels go back into the river after we identify the species and estimate their age using the shell structure and measure their length. These surveys are critical to tracking the diversity and abundance of freshwater mussels in Canada's rivers.
Left: Scanning electron microscope image of the mandible of a springtail (Folsomia candida). An important fungivore found in soil across the globe. This little critter is readily used in soil toxicity testing.
Right: Tetrahymena glochidiophila feeding on a glochidium (larval mussel) of freshwater mussels (Lampsilis siliquoidea, fatmucket mussel). This tiny ciliate was described for the first time by Dr. Ryan Prosser and Dr. Denis Lynn. This means that Denis and I got to name the little critter, we decided on the species name "glochidiophila" (lover of glochidia).