Current Graduate Students
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.
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.
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.
Lauren Negrazis, MSc Candidate
Honors Specialization in Biodiversity and Conservation, University of Western Ontario.
Contact: negrazla(a)mcmaster.ca
Research: "Exploring the impact of forestry on mercury levels in stream food webs in New Brunswick"
New Brunswick depends on forestry more than any other province in the country. With 83% of the land covered by forest it is crucial to be conscious of the impacts harvesting practices have on the surrounding environment both terrestrial and aquatic. Terrestrial and aquatic systems connect to each other through the exchange of organic and inorganic substances. Recently there has been a focus if disturbances from forestry are increasing the mobilization of mercury into aquatic systems.
My research will assess components of stream health and compare water quality to the bioaccumulation of methyl mercury (a neurotoxin) in headwater stream food webs comprised of invertebrates and fish. Samples will be taken across a gradient of streams that exist in watersheds that are less to more intensively logged within New Brunswick.
The results of this study will fill in a knowledge gap about how anthropogenic disturbance influences heavy metal accumulation in headwater streams in New Brunswick. This will help us better understand possible implications on the health of the fauna living in this system and stimulate future research to see if forestry practices can be improved.
Honors Specialization in Biodiversity and Conservation, University of Western Ontario.
Contact: negrazla(a)mcmaster.ca
Research: "Exploring the impact of forestry on mercury levels in stream food webs in New Brunswick"
New Brunswick depends on forestry more than any other province in the country. With 83% of the land covered by forest it is crucial to be conscious of the impacts harvesting practices have on the surrounding environment both terrestrial and aquatic. Terrestrial and aquatic systems connect to each other through the exchange of organic and inorganic substances. Recently there has been a focus if disturbances from forestry are increasing the mobilization of mercury into aquatic systems.
My research will assess components of stream health and compare water quality to the bioaccumulation of methyl mercury (a neurotoxin) in headwater stream food webs comprised of invertebrates and fish. Samples will be taken across a gradient of streams that exist in watersheds that are less to more intensively logged within New Brunswick.
The results of this study will fill in a knowledge gap about how anthropogenic disturbance influences heavy metal accumulation in headwater streams in New Brunswick. This will help us better understand possible implications on the health of the fauna living in this system and stimulate future research to see if forestry practices can be improved.
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Jenni Velichka, MSc candidate
HBSc Biology and Environmental Studies, Queen’s University
Contact: velichkj(a)mcmaster.ca
Research: "Contaminants and nutrients in the subsistence fisheries of the Saint John River: do benefits outweigh risks?"
The Mactaquac Generating System is a 672 MW run-of-the-river hydroelectric facility on the Saint John River (SJR) that generates approximately 12% of New Brunswick’s power. However, the implementation of the dam has altered the natural flow of the SJR, which can have additional impacts on the aquatic biota.
One concern regarding the dam is that the creation of a reservoir increases the mobilization of methylmercury (MeHg) through the bacterial methylation of Hg (II) found in flooded soils. This in turn increases MeHg availability to aquatic organisms, leading to bioaccumulation of the toxin in top predators. Many First Nations communities depend on subsistence fishing in the SJR and benefit from the nutritional value of micronutrients, particularly fatty acids, in the fish. However, they may consequently be experiencing higher exposure to mercury as a result of the dam.
This experiment aims to work with members of the Wolastoqey First Nations in New Brunswick by using a subsample of their subsistence fish yield to measure the concentration of mercury, fatty acids and other micronutrients in their fish. This will provide data to compare potential health benefits versus risks of consuming fish from the SJR and can help inform health experts on recommendations for fish consumption.
HBSc Biology and Environmental Studies, Queen’s University
Contact: velichkj(a)mcmaster.ca
Research: "Contaminants and nutrients in the subsistence fisheries of the Saint John River: do benefits outweigh risks?"
The Mactaquac Generating System is a 672 MW run-of-the-river hydroelectric facility on the Saint John River (SJR) that generates approximately 12% of New Brunswick’s power. However, the implementation of the dam has altered the natural flow of the SJR, which can have additional impacts on the aquatic biota.
One concern regarding the dam is that the creation of a reservoir increases the mobilization of methylmercury (MeHg) through the bacterial methylation of Hg (II) found in flooded soils. This in turn increases MeHg availability to aquatic organisms, leading to bioaccumulation of the toxin in top predators. Many First Nations communities depend on subsistence fishing in the SJR and benefit from the nutritional value of micronutrients, particularly fatty acids, in the fish. However, they may consequently be experiencing higher exposure to mercury as a result of the dam.
This experiment aims to work with members of the Wolastoqey First Nations in New Brunswick by using a subsample of their subsistence fish yield to measure the concentration of mercury, fatty acids and other micronutrients in their fish. This will provide data to compare potential health benefits versus risks of consuming fish from the SJR and can help inform health experts on recommendations for fish consumption.
Ellie Weir, MSc Candidate
Bachelor of Health Sciences (Honours), McMaster University
Contact: weire1(a)mcmaster.ca
Research: “Quantification of microplastics near municipal wastewater treatment plant outfalls”
My MSc research focuses on microplastics accumulation in biotic and abiotic compartments downstream of two major wastewater treatment plants (WWTPs) along the Grand River, ON, Canada. Microplastics are ubiquitous environmental pollutants measuring <5mm in size that can vary in size, colour, polymer composition, and chemical additives. Not only do these particles act as physical stressors, but they can also serve as both a source and a sink for harmful chemicals. Consumption of microplastics by organisms has been shown to cause inflammation, changes in gene expression, and a reduction in consumption of natural prey.
Microplastics have previously been detected in WWTP effluents, although it is unclear whether these particles are consumed by biota living near these discharges. I hope to deepen our understanding of how anthropogenic particles move through freshwater systems and determine whether efforts need to be made to reduce inputs of microplastics from WWTPs.
Bachelor of Health Sciences (Honours), McMaster University
Contact: weire1(a)mcmaster.ca
Research: “Quantification of microplastics near municipal wastewater treatment plant outfalls”
My MSc research focuses on microplastics accumulation in biotic and abiotic compartments downstream of two major wastewater treatment plants (WWTPs) along the Grand River, ON, Canada. Microplastics are ubiquitous environmental pollutants measuring <5mm in size that can vary in size, colour, polymer composition, and chemical additives. Not only do these particles act as physical stressors, but they can also serve as both a source and a sink for harmful chemicals. Consumption of microplastics by organisms has been shown to cause inflammation, changes in gene expression, and a reduction in consumption of natural prey.
Microplastics have previously been detected in WWTP effluents, although it is unclear whether these particles are consumed by biota living near these discharges. I hope to deepen our understanding of how anthropogenic particles move through freshwater systems and determine whether efforts need to be made to reduce inputs of microplastics from WWTPs.
