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
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
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.
Elise Millar, MSc candidate
HBSc Biochemistry & Molecular Biology, Trent University
Contact: millae1(a)mcmaster.ca
Research: "The gut microbiome of mussels and macroinvertebrates upstream and downstream WWTPs on the Grand River"
The gut microbiome is a new and exciting area of research, with recent studies linking it to overall organismal health and function. The composition of the gut microbiota can influence various physiological qualities (e.g. weight, immune function, disease), and is sensitive to a variety of factors (e.g. diet, environment, pharmaceutical use).
Effluents from the Kitchener and Waterloo wastewater treatment plants in Ontario may affect species living in the Grand River as the wastewaters contain antibiotics and pharmaceuticals that may negatively impact the gut microbiome aquatic biota. To determine these impacts, I will be sampling Long-jawed Orb Weavers (Tetragnathidae), Flutedshell mussels (Lasmigona costata), and a variety of aquatic macroinvertebrate taxa from sites along the Grand River in the Kitchener-Waterloo area, Ontario. I will then be analyzing the gut microbiota of these organisms using bioinformatics techniques to determine if and how its composition changes between sites.
At present, the gut microbiome is still poorly understood in aquatic organisms and this research will add to the growing knowledge on how factors such as diet and exposures affect its composition. It will also shed light on the impacts of wastewater effluent on the overall health of benthic and riparian organisms.
HBSc Biochemistry & Molecular Biology, Trent University
Contact: millae1(a)mcmaster.ca
Research: "The gut microbiome of mussels and macroinvertebrates upstream and downstream WWTPs on the Grand River"
The gut microbiome is a new and exciting area of research, with recent studies linking it to overall organismal health and function. The composition of the gut microbiota can influence various physiological qualities (e.g. weight, immune function, disease), and is sensitive to a variety of factors (e.g. diet, environment, pharmaceutical use).
Effluents from the Kitchener and Waterloo wastewater treatment plants in Ontario may affect species living in the Grand River as the wastewaters contain antibiotics and pharmaceuticals that may negatively impact the gut microbiome aquatic biota. To determine these impacts, I will be sampling Long-jawed Orb Weavers (Tetragnathidae), Flutedshell mussels (Lasmigona costata), and a variety of aquatic macroinvertebrate taxa from sites along the Grand River in the Kitchener-Waterloo area, Ontario. I will then be analyzing the gut microbiota of these organisms using bioinformatics techniques to determine if and how its composition changes between sites.
At present, the gut microbiome is still poorly understood in aquatic organisms and this research will add to the growing knowledge on how factors such as diet and exposures affect its composition. It will also shed light on the impacts of wastewater effluent on the overall health of benthic and riparian organisms.
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.
Victoria Restivo, MSc Candidate
BScH Life Science, Specializing in Environmental Science, Queen’s University Contact: restivve(a)mcmaster.ca Research: "The impact of exposure to wastewater treatment plant effluent on the microbiome of Rainbow Darter (Etheostoma cartuleum)" At present, microbiome studies are at the forefront of scientific research as the microbiome has been discovered to play an integral role in overall organismal health and well being. Research has shown that microbial interaction with the host immune system is responsible for maintaining the host’s health. There are many factors that influence the microbiome, including the environment. My research focuses on studying the response of Rainbow Darter (E. cartuleum) gut microbiota after exposure to varying concentrations of wastewater effluent in sites along the Grand River (Kitchener and Waterloo, Ontario). Fish gut contents are sampled from multiple locations along the Grand River, upstream and downstream of wastewater treatment plants, and later analyzed using bioinformatics tools to determine the species and function of microbiota present between different locations. Additionally, in the lab fish are exposed to varying concentrations of wastewater effluent and again analyzed to determine the effect on gut microbiota and fish health. This research will contribute to a greater understanding of the response of the fish gut microbiome as an indicator of health after exposure to a variety of emerging and legacy contaminants in wastewater treatment plant effluent. |
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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.
