Current Graduate Students
Shawn Kroetsch, MSc candidate
BSc Biology, University of New Brunswick Saint John
Contact: shawn.kroetsch(a)unb.ca
Research: “Investigating the effects of habitat and functional feeding type on the composition of the gut microbiota of freshwater aquatic macroinvertebrates in the Saint John River, New Brunswick.”
The collections of bacteria that inhabit the digestive tracts of living organisms, known as the gut microbiota, provide several beneficial functions to their hosts. When the identity of these bacteria becomes altered significantly, for reasons not yet understood in aquatic macroinvertebrates, the beneficial services cease to be provided to the host. Currently, little information is known regarding how habitat type and functional feeding type impact the composition of the gut microbiota of aquatic macroinvertebrates.
For my project, I will be sampling several taxa of aquatic macroinvertebrates from various habitats in the Saint John River, New Brunswick. The gut microbiota of these organisms will be characterized using next-generation genetic sequencing techniques in order to establish how the composition of the gut microbiota changes based on differing habitat and functional feeding type.
Since the study of the aquatic macroinvertebrate gut microbiota is relatively new and underexplored, this project will reveal details about the associations that these organisms share with bacteria, which will aid in establishing a baseline of natural variability. It is essential to determine this information before these techniques can be used to assess human impacts and provide better management and conservation practices within aquatic habitats.
BSc Biology, University of New Brunswick Saint John
Contact: shawn.kroetsch(a)unb.ca
Research: “Investigating the effects of habitat and functional feeding type on the composition of the gut microbiota of freshwater aquatic macroinvertebrates in the Saint John River, New Brunswick.”
The collections of bacteria that inhabit the digestive tracts of living organisms, known as the gut microbiota, provide several beneficial functions to their hosts. When the identity of these bacteria becomes altered significantly, for reasons not yet understood in aquatic macroinvertebrates, the beneficial services cease to be provided to the host. Currently, little information is known regarding how habitat type and functional feeding type impact the composition of the gut microbiota of aquatic macroinvertebrates.
For my project, I will be sampling several taxa of aquatic macroinvertebrates from various habitats in the Saint John River, New Brunswick. The gut microbiota of these organisms will be characterized using next-generation genetic sequencing techniques in order to establish how the composition of the gut microbiota changes based on differing habitat and functional feeding type.
Since the study of the aquatic macroinvertebrate gut microbiota is relatively new and underexplored, this project will reveal details about the associations that these organisms share with bacteria, which will aid in establishing a baseline of natural variability. It is essential to determine this information before these techniques can be used to assess human impacts and provide better management and conservation practices within aquatic habitats.
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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Carson White, MSc candidate
BSc Natural Resources Conservation, University of British Columbia
Contact: carson.f.white(a)gmail.com
Research: "Cumulative effects of forest management on fish communities in northern New Brunswick"
Forest management is an important contributor to the economy of New Brunswick, but can have implications on ecosystem health. Changes to hydrologic processes, energy cycling and habitat structure can have effects on the aquatic communities. Best management practices in forestry have been largely effective in minimizing historical impacts to headwater streams, but large-scale effects are less known.
For my project, I will be looking at how cumulative downstream effects from forest management are expressed in fish communities draining harvested catchments. I will be using a fish condition factor (weight-length ratio) to examine potential differences in fish health between intensive and extensive forest management.
The effects of forest management on headwater streams is well studied and reasonably predictable, but less is known about the effects on downstream habitats. Do headwater effects accumulate throughout the system and have measurable downstream impacts or do they dissipate with increasing stream size? The results from this research project will be important in identifying catchment scale impacts from forest management.
BSc Natural Resources Conservation, University of British Columbia
Contact: carson.f.white(a)gmail.com
Research: "Cumulative effects of forest management on fish communities in northern New Brunswick"
Forest management is an important contributor to the economy of New Brunswick, but can have implications on ecosystem health. Changes to hydrologic processes, energy cycling and habitat structure can have effects on the aquatic communities. Best management practices in forestry have been largely effective in minimizing historical impacts to headwater streams, but large-scale effects are less known.
For my project, I will be looking at how cumulative downstream effects from forest management are expressed in fish communities draining harvested catchments. I will be using a fish condition factor (weight-length ratio) to examine potential differences in fish health between intensive and extensive forest management.
The effects of forest management on headwater streams is well studied and reasonably predictable, but less is known about the effects on downstream habitats. Do headwater effects accumulate throughout the system and have measurable downstream impacts or do they dissipate with increasing stream size? The results from this research project will be important in identifying catchment scale impacts from forest management.
