Lab group - summer 2016
Kelli Charbonneau, MSc candidate
Honours BSc Environmental Toxicology, Queen's University
Research: “Cumulative effects of forest management on stream food webs in the Batchawana watershed, Ontario”
Forest management activities in Canada’s boreal zone are ecologically linked to the structure and biodiversity of their adjacent aquatic systems. Forest harvesting, road construction, and pesticide application impact not only forest and soil composition in terrestrial environments, but also biogeochemical cycling, nutrient concentration, and sediment and organic matter input in aquatic environments.
My research will focus on analyzing a variety of environmental parameters (leaf litter decomposition, sediment deposition, water chemistry, etc.) and food web structure in streams in the Batchawana watershed, Ontario. Streams studied were chosen across a range of forest management intensity to help link anthropogenic disturbance and forest condition with environment impacts. A comprehensive and predictive understanding of the cumulative effects associated with forest management is critical to maintaining healthy future forest and aquatic system conditions.
This project will contribute to a larger research network, the Canadian Network for Aquatic Ecosystem Services, which examines how watershed disturbances influence the provision of ecosystem services from Canada’s aquatic environments to both humans and our non-human friends.
Maitane Erdozain, PhD candidate
BSc Biology, University of Basque Country (Spain)
MSc Sustainable Water Management, University of Kristianstad (Sweden)
Research: “Food web structure and element storage in food webs across a range of forest conditions in New Brunswick”
My main research interests are stream ecology and the link between streams and their riparian zone and watershed. In particular, I am concerned by how human watershed disturbances (mainly forestry) affect stream ecosystems and the ecosystem services they provide.
During my PhD I will address the question of how forest condition affects stream productivity and biodiversity. More specifically, my project will look at food web structure and how elements (C, N and P) are stored in these food webs across a range of forest conditions. These conditions will range from undisturbed forests to forests disturbed both by humans (e.g. logging) and by nature (e.g. fire).
The watersheds of my project will be located in the province of New Brunswick. However, the project is part of the Canadian Network for Aquatic Ecosystem Services (CNAES), and I will be working closely with other PhD candidates that will be doing a complementary work in other Canadian provinces.
Jon Fischer-Rush, MSc candidate
BSc Biology, McGill University
Research: "Uptake of nutrients and metals from salmon aquaculture into benthos in the Bay of Fundy"
Aquaculture has been present in the Bay of Fundy for over 30 years and it is a large part
of the New Brunswick economy. However, inputs of nutrients and contaminants from feed, salmon byproducts and antifouling agents on nets may be having negative impacts on the benthic communities surrounding these farms. It is not clear whether nearby invertebrates, including lobster, incorporate these wastes into their tissues.
This is why, over the next two years, I plan on collecting three invertebrate species, each with a different feeding strategy, using artificial substrates and sediments from aquaculture and reference sites. Using stable isotopes of carbon, nitrogen and sulfur and metals analyses, I will examine whether there is uptake of these elements into the species near salmon pens.
This research will advance our understanding of the potential impacts of salmon aquaculture on nearby environments and aid in future management plans for fisheries in the Bay of Fundy. This includes understanding the impact of aquaculture on lobster and whether or not it is beneficial or detrimental for the iconic crustacean.
Shawn Kroetsch, MSc candidate
BSc Biology, University of New Brunswick Saint John
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.
Heather Loomer, PhD candidate
MSc Biology, University of Waterloo
BSc, University of New Brunswick
Research: “Effects of agriculture on nutrient storage within the food webs of headwater streams”
Small headwater streams are critical for maintaining flows, water quality and aquatic communities downstream in the larger river system. These small streams are strongly connected to the landscape and are often affected by human activities in the watershed.
Agriculture, one of the most common stressors, can change the habitat, metabolism, and aquatic communities in streams as well as other important functions of these systems. The Grand Falls region of New Brunswick is an area of intense agricultural activity within the Saint John River Valley.
Previous studies have shown that water quality and biological communities are impaired in streams in areas with high agriculture. The objective of my PhD work is to build on the previous work by studying how agriculture affects the functioning of stream ecosystems in this region. This will be accomplished by monitoring stream conditions (i.e., water quality) within the region while assessing relative differences in the capacity of the food webs to harness available resources (i.e. nutrient storage), a critical function of a healthy ecosystem. These results will be combined with the earlier studies to better understand which conditions are predictive of how small stream food webs function and are affected by agriculture.
Bethany Reinhart, MSc candidate
BSc, University of New Brunswick Saint John
Research: “Mercury contamination in fish along salinity gradients of estuaries in New Brunswick.”
Mercury (Hg) in its organic form, methylmercury (MeHg), has been shown to have negative physiological, behavioural and reproductive effects on fish. Previous studies have observed that fish from freshwater areas in rivers can have higher Hg concentrations compared to their estuarine or marine neighbours.
For my project, I will be measuring total Hg contamination (total Hg is typically 95% MeHg in fish) in fish and invertebrates in three New Brunswick estuaries. I will be looking at how Hg concentrations change within the animals as water becomes more saline within the estuaries. Also, I will be investigating the potential sources of the contaminants (whether they are marine, freshwater, etc.) by measuring carbon and sulfur stable isotopes.
Since there is little known about Hg within New Brunswick estuaries and its accumulation in estuaries in general, this is a topic that should be explored. The results will be important for identifying sites and species at higher risk of Hg toxicity.
Jennifer Thera, PhD candidate
MSc Environmental Science, Florida Gulf Coast University
BSc Marine Science, Eckerd College
Research: “Among-lake variability in methylmercury and cysteine content through aquatic food webs”
Kejimkujik National Park, Nova Scotia, Canada was designated as a biological hotspot based on the elevated concentrations of methylmercury (MeHg) in fish and fish-eating wildlife. Previous studies, within in the park, to model MeHg concentrations in biota using delta15N (a measurement of trophic position) have not been able to completely explain the variability in taxa within or among the lakes or the high concentrations found in top level consumers.
My research will build upon this previous work to examine a novel method for modeling MeHg concentrations in biota. Since MeHg is stored in proteins and bound to the amino acid cysteine, the cysteine content may prove to be a more consistent predictor of MeHg in organisms.
The objective of my PhD research is to examine the current concentrations of MeHg and amino acids (cysteine especially) in invertebrates and fish, from a subset of lakes that we have already studied, to determine whether cysteine content better explains the variability of MeHg in invertebrates and its movement through aquatic food webs than trophic position.
Carson White, MSc candidate
BSc Natural Resources Conservation, University of British Columbia
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.