My applied research program encompasses the areas of environmental physiology, biochemical toxicology, and aquatic toxicology. Our studies are integrative in nature and move from whole organismal to cellular and molecular responses, using a wide variety of techniques. Much of our research is experimental, laboratory based studies but we also perform field based research using native or invasive species. Our interest is in the study of aquatic vertebrates, primarily fish but also a strong interest in marine mammals. Most recently, we have begun to use two aquatic invertebrates, hydra and the marine annelid Capitella tellata, for our toxicological studies. In our fish studies, we use zebrafish and rainbow trout as our primary model species in the laboratory. By nature, the research is comparative and integrative.
Impacts of Pharmaceuticals in the Aquatic Environment
Much research has documented that human pharmaceuticals are present in our surface waters due to release with wastewater effluent. The release of pharmaceuticals into the environment is a large concern because these compounds are designed with inherent biological activity and physiological pathways are highly conserved across vertebrates. Thus, we expect that pharmaceuticals will have biological activity in aquatic vertebrates such as fish. Our research has focused on four major pharmaceuticals consistently found in wastewater effluent and surface waters: acetaminophen (common analgesic), carbamazepine (anti-epileptic and mood stabilizer), gemfibrozil (lipid regulator), and venlafaxine (anti-depressant). Using environmentally relevant concentrations and chronic exposures, we have exposed zebrafish to single pharmaceuticals, pharmaceutical mixtures and diluted wastewater effluent to assess reproductive, developmental, histological, transcriptomic and multi-generational impacts. We are exploring whether the effects of exposure to these compounds are through their mechanism of action in humans. We use rainbow trout to determine the physiological implications of pharmaceutical exposure in fish. We are currently developing the use of hydra to study the effects of pharmaceuticals on aquatic species. This research uses a wide array of techniques from basic histology and enzyme immunoassays, to microarray and microinjection approaches.
Zebrafish sperm. We are examining sperm morphology and swimming speed as relevant endpoints for male offspring after parental exposure to pharmaceuticals.
Endocrine Disrupters in Hamilton Harbour and the Great Lakes Region
Round goby are a benthic, territorial invasive species in the Great Lakes Basin. We are using gobies to study endocrine disrupters in Hamilton Harbour because they are one two species in Hamilton Harbour and Cootes Paradise with intersex, the presence of both egg and sperm in male testes. Our research has focused on understanding feminization (intersex or ovo-testis; feminized urogenital papilla, expression of egg related genes in males) of round gobies at sites with historical industrial pollutants, combined sewer overflow, and wastewater effluent discharge. The complicated discharge at many of these sites makes it difficult to discern if the feminization of fish is related to steroids or other pharmaceuticals in the environment, as originally proposed, or due to historical PAH type contaminants. Round goby are ideal for this research because they do not have a wide range and thus its contaminant exposure will reflect local pollution. We have developed a quantitative PCR method for monitoring vitellogenin gene expression in male gobies. Vitellogenin, an egg yolk precursor protein, should not be expressed in males unless they have been exposed to a natural or xeno-estrogen. We hope to identify sites polluted with endocrine disrupters within Hamilton Harbour and the Great Lakes Region and determine what contaminants are causing the endocrine disruption.
Thermal and Multiple Stressor Effects on Whitefish
Lake and round whitefish are cold water adapted fish which spawn in late fall. Embryos develop overwinter at low temperatures. We study the effects of temperature alone, and in combination with other stressors, on developing whitefish. This work is important to understand the impacts of once through cooling, a common process used in many industrial processes including power plants. This research is also important for understanding effluent impacts on Canadian receiving waters because many effluent discharges are warmer than ambient water. We are examining both the direct effects on development, including morphology, survival, and hatching, as well as the longer term implications of embryonic exposures for juvenile fish. Our research will help us to understand the impacts of temperature on the development of an important native fish in the Great Lakes region.
Want to see a great video explaining our whitefish project? Caitlin, an undergraduate in the lab in 2016-2017 academic year, won best video in the iClimate Video Competition. Check out her video here!
This research has been funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) Strategic Project and Collaborative Research and Development Programs, the Canadian Water Network (CWN), Ontario Ministry of Research and Innovation Early Researcher Award program, and industrial partners.