Environmental Stressors Research

Aquatic Stressors

My applied research program encompasses the areas of environmental physiology,   and 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.  Often our field work is associated with bringing native species into the lab.  Our interest is in the study of aquatic species, primarily fish but we have begun to use two aquatic invertebrates, the freshwater hydra and the marine annelid Capitella tellata.  In our fish studies, we use a wide variety of species including zebrafish, rainbow trout, arctic charr, lake and round whitefish, and yellow perch.  By nature, the research is comparative and integrative.

Impacts of Pharmaceuticals in the Aquatic Environment

Pharmaceuticals cause histological changes in zebrafish kidney

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).  Most recently, we have started to experiment with metformin, a type 2 diabetes medication.

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 also determined effects on the brown and green hydra, important freshwater cnidarians! 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.

Thermal Stressor Effects on Fish Development

Developing Lake Whitefish Embryos

Lake and round whitefish are cold water adapted fish which spawn in late fall.  Embryos develop overwinter at very low temperatures, typically between 0 and 2 degrees Celsius. Yellow perch are cool water adapted fish which spawn in spring, developing in warming water.  Interestingly, perch do not lay individual eggs but release them in a long ribbon.  We capture spawning adults and either generate embryos from in vitro fertilization or allow the fish to spawn in tanks in the lab. The field work is fun but cold!  The embryos, like zebrafish, have a clear chorion (equivalent to an egg shell), which allows us to examine them under microscope and see their development in real time.

We study the effects of temperature on developing fish to assess the impacts on embryogenesis and later in life.  For these experiments, we manipulate developmental temperature and then move the hatched fish into common garden (i.e. similar) conditions.  This research serves two purposes.  One obvious purpose is to understand the impacts of climate change.  The second, less obvious, purpose is  to understand the impacts of once through cooling, a common process used in many industrial processes including power plants.  Many effluent discharges are warmer than ambient water and if fish spawn in impacted waters, the embryos can’t move or avoid the elevated temperatures.  For direct effects on embryogenesis, we examine changes in development, morphology, survival, heart rate, oxygen consumption, gene expression, and hatching.  In the post-hatching phase, we examine survival, time to first foods, behaviour, and thermal preferences. This research will help us to understand the impacts of temperature on the development of  important native fishes in the Great Lakes region.

Want to see a great video explaining our whitefish project?  Caitlin, an undergraduate from 2016-2017, 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; Discovery, Strategic Project, and Collaborative Research and Development Programs), MITACs, the Canadian Water Network (CWN), Ontario Ministry of Research and Innovation Early Researcher Award program, and industrial partners.

Recent Posts

Research Leave is where?

Research leave has rolled around and again, it seems to follow family catastrophe.  I *thought* we would be in Bergen, Norway right now but new elder care duties seriously cancelled that plan. So now I am local.  Research Leave in Hamilton!!!  At the end, it looks like COVID might have cancelled things anyways because I am not sure relocating in the middle of the largest wave of the pandemic would have been so attractive.  Still, it was Norway and I am missing the sea.

My priority for research leave has always been to do something significant for my research program.  For my first, I spent 13 months in Sweden and this was where I fist started doing behavioural research with fish.  I also learned to experiment with primary hepatocytes, although this hasn’t been incorporated in my lab in the same way.  That is mostly because the results of the experiments were a bit blah and unexciting for the compounds we were testing in hepatocyte culture.  But the behavioural research is a different story.  Now we have added in a suite of behavioural assays in different life stages.  For juvenile and adults, we have used courtship, aggression, behavioural choice experiments with odorants and thermal preference tests. For larval fish, we now do a whole range of swimming (general swimming, light:dark response, thigmotaxis), startle responses and feeding behaviour.  My year away pushed us in a new direction that has been rewarding.

So what is on the table this year?  Planning is still an active process but one thing is for sure is that I have some training and planning to do. First, is training to work with human subjects as we have some projects that will cross into social sciences.  The other major training need is to brush up on transcriptomics analyses and R so that we are better equipped for some of the new data we will be generating in the next few years.  Second, is planning for both the lab and field for our perch embryo experiments. We learned so much from last year’s experiments and have to adjust. We will adjust the lab for better rearing protocols and really minimize some of the labour issues we encountered last year. We are adding  new lights to help with feed training the larval fish too. We are also adjusting our field sites and I need to get new permits in place. This is really exciting and I already have new Windermere traps under construction with the engineering lab.  I can’t wait for perch spawning.

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