Summer 2022
Current Graduate Students
Quinn Allamby, MSc Candidate
BSc, University of Guelph Contact: allambyq@mcmaster.ca Research: "Toxicity and accumulation of microplastics in freshwater invertebrates" Microplastics are a ubiquitous contaminant that pose a major threat to organisms living in aquatic environments. These plastics are generally defined as particles smaller than 5mm, and can vary widely in their characteristics, such as polymer type and size. The effects that microplastics have on many freshwater organisms, such as invertebrates, are currently widely unknown, however, understanding how they are impacted is incredibly valuable. Invertebrates form the basis of many environmentally and economically important food webs and understanding how these particles are impacting these organisms is crucial in conserving the overall health of freshwater ecosystems. My project aims to assess the toxicity and accumulation of a variety of microplastic sizes and polymer types on different freshwater invertebrates using environmentally relevant concentrations. I hope that this research will help to propel the future field of microplastic research and help to quantify the effects of microplastics on freshwater invertebrates. 
Emilie Diesbourg, MSc Candidate
BSc Marine Biology (Honours), University of New Brunswick Saint John Contact: diesboue(a)mcmaster.ca Research: "Influence of wastewater effluents on microbiomes of downstream macroinvertebrates and riparian spiders" The gut-associated microbiome is vital to the health of the host as it maintains homeostasis and protects against pathogens. Aquatic ecosystems receive a vast amount of nutrients and pharmaceuticals from municipal wastewater effluent that can potentially alter the normal composition of these essential microorganisms, resulting in dysbiosis. Despite wastewater being the largest source of pollution to surface water in Canada, there is a lack of knowledge on the influence of these pollutants to microbial compositions within downstream organisms. Chemicals and nutrients can also be transferred beyond contaminated areas by physical and biological vectors, such as emergent aquatic insects, thus determining the fate of these contaminants is a crucial step to mitigating risks associated with environmental health. My research contributes to a larger collaborative project focusing on the ecological state of the Bow River in Calgary, AB, an essential watershed serving nearly 1.5 million people. My study addresses the effects of exposures to wastewater treatment plant (WWTP) effluents on the gut microbiome of downstream macroinvertebrates in the Bow River, Calgary, AB and whether these effects are then transferred to nearshore spiders via emergent insects. These results may be used to identify potential detrimental microbial imbalances resulting from contaminant exposure. 
John Fast, MSc Candidate
HBSc Earth and Environmental Science, McMaster University Contact: fastjj(a)mcmaster.ca Research: "Antimicrobials in aquatic organisms in waters affected by wastewater treatment plant effluent" Antimicrobial agents, including Triclosan and its associated metabolites, in many personal care products have been found to be prevalent in municipal wastewater treatment plant (WWTP) effluent. When this effluent is returned to the watershed after treatment, elevated levels of antimicrobial compounds can remain and have been shown to negatively affect the health of aquatic organisms. Other studies have demonstrated the potential of these compounds to cause changes in reproductive capabilities and the gut microbiome in certain aquatic species. The focus of my research will be to quantify the presence of these compounds in freshwater fish and mussels exposed to WWTP effluent in the Grand River, southern Ontario. This project will hopefully be able to establish a link between antimicrobial concentrations present in aquatic organisms and previous studies into their effects on overall ecosystem health. This may also contribute to further research into the trophic transfer of these compounds along the Grand River. 
Sally Ju, MSc Candidate
BSc, University of Waterloo Contact: ksju(a)uwaterloo.ca Research: "Effects of spruce budworm outbreaks on mercury fate in streams" The spruce budworm is a pest native to North America that defoliates spruce and fir trees. Cyclical outbreaks have occurred every 30-40 years over several centuries. Over 7 million hectares of forest have been defoliated in Eastern Canada, and there is currently an outbreak in the Gaspesie region of Quebec. My research is part of a multidisciplinay project to investigate the ecosystem effects of spruce budworm defoliation in forest stands on the Gaspe peninsula. I will use a paired study design to compare watersheds with active defoliation and control watersheds without defoliation. I will evaluate the effects on stream ecosystems by measuring mercury cycling, aquatic communities, and fish health. This is a novel study to investigate the aquatic effects of terrestrial defoliation, which is believed to become a greater threat as climate change increases the viability of insect outbreaks. 
Celine Lajoie, PhD Candidate
M.Sc. Environmental Science - University of Windsor B.Sc. Biological Sciences with Thesis (Honours) - University of Windsor Contact: lajoic1(a)mcmaster.ca Research: "The effects of forestry best management practices on mercury in boreal stream food webs" Mercury (Hg) is a contaminant of global concern and its fate in forested ecosystems is known to be affected by forestry through effects on its transport and deposition, as well as changes in carbon inputs and food web structure. Harvesting activities create conditions that enhance Hg methylation to its more toxic form, methyl mercury (MeHg), and increase the movement of Hg from soils to surface waters. The biomagnification of MeHg in aquatic food webs can lead to critically high levels of Hg in fish and increase the risk to fish consumers. To reduce the environmental impacts of harvest operations, the forestry industry uses best management practices (BMPs) to achieve sustainable forestry and management objectives. BMPs include creating buffer zones near streams and reducing impacts of road construction by installing ditches/water diversion bars. Although BMPs are effective in minimizing soil and hydrologic disturbances, little research exists on their effectiveness at preventing MeHg bioaccumulation in nearby streams. The main objective of my research is to identify BMPs that effectively reduce the bioaccumulation and biomagnification of MeHg in stream food webs. Specifically, I will be testing the effectiveness of different BMP combinations across three harvest regions near Dryden, Ontario. This research involves characterizing the structure of stream food webs and MeHg in biota at sites with and without harvesting and with different BMPs to identify those that are effective at minimizing MeHg levels in aquatic food webs. 
Madison McCaig, MSc Candidate
BSc in Environmental Science (Honours), University of Ottawa Contact: mccaigml(a)mcmaster.ca Research: "Effects of spruce budworm defoliation on stream ecosystem functions" Spruce budworm is a forest pest native to North America which feeds on spruce and fir trees. Cyclical outbreaks of this species occur every 30-40 years, and have resulted in the defoliation of millions of hectares of forest across Canada. My research is part of a multidisciplinary project investigating the impacts of spruce budworm defoliation on biological communities, habitats, and ecosystem processes in forested watersheds in the Gaspesie area of Quebec. The study design of this project allows for the comparison of defoliated watersheds and control watersheds (that are not defoliated), both before and after an outbreak. My research recognizes the critical linkage between forest and aquatic ecosystems. I will investigate how spruce budworm defoliation effects stream ecosystem functions by looking at the response of microbial communities. I will use eDNA and genomic methods to determine which microbe taxa are present and what their main biogeochemical functions are (e.g. carbon cycling or nutrient cycling). The results of this study will be useful to inform forest pest management activities. An improved understanding of the impacts of forest pests on aquatic ecosystems will be increasingly important in the future as the incidence of forest pest outbreaks is expected to increase with climate change. 
Emily Robson, MSc Candidate
BSc (Honours), Memorial University of Newfoundland Contact: robsoe4(a)mcmaster.ca Research: "Wastewater treatment plants as a source of microplastics to the Grand River, southern Ontario" Microplastics are an emerging contaminant and are persistent and ubiquitous in nature. Prevalence of microplastics in the marine environment are being studied extensively, but there are many knowledge gaps in freshwater ecosystems. A potential source of microplastics and other pollutants in fresh waters are municipal wastewater treatment plants. The focus of my research is the presence and abundance of microplastics in freshwater mussels upstream and downstream of wastewater treatment plants along the Grand River in southern Ontario. Research has been conducted to assess the general impacts of wastewater on freshwater mussels, but this study will focus on the specific impacts of microplastics. The concentration, size, shape, and type of microplastics present in wastewater effluent, surface water, sediment, and organisms will be assessed. My project is part of a larger research project that will analyze the impacts of microplastics in terrestrial and aquatic ecosystems. This research compliments lab studies examining the toxicity of microplastics to freshwater mussels. 
Colleen Wardlaw, PhD Candidate
MSc Ecology - University of Western Ontario BSc Environmental Science - University of Guelph Contact: wardlac(a)mcmaster.ca Research: “The transfer of microplastics from aquatic to terrestrial foodwebs and impacts on emergent insects near municipal wastewater treatment plants” Microplastics (plastic particles < 5mm) are recognized as widespread contaminants in the environment, and wastewater treatment plant outfalls are a source of microplastics to aquatic environments. Due to their small size and ubiquity, microplastics may be ingested by a wide variety of organisms and cause adverse effects such as oxidative stress, impaired development and reproduction, reduced growth, impaired mobility, endocrine disruption and mortality. However, few studies consider the impacts of microplastics on emergent insect communities and their capacity to carry microplastics from aquatic habitats to riparian areas as emerged adults. Further, trophic transfer of microplastics from emerged insects may impact food webs, as little is known about how riparian predators are exposed to and impacted by microplastics. My study will take place at municipal wastewater treatments plants in the Grand River watershed, Ontario, and will quantify the amount of microplastics being ingested by larval insects, examine the potential transfer of microplastics from aquatic to terrestrial ecosystems through emerged insects to riparian predators and investigate how microplastics may be affecting metamorphosis and emergence of insects. This study is part of a larger investigation characterizing the exposure, effects and risks of microplastics to freshwater and terrestrial ecosystems in Canada. Lab Pictures
 Spring 2021
 Summer 2020
Our award-winning Halloween costume - 2020
|
