Research
Current Research
Regional thermal variation in a coral reef fish (Acanthochromis polyacanthus)
How species respond to climate change will depend on the collective response of populations. Intraspecific variation in traits, evolved through genetic adaptation and phenotypic plasticity, can cause thermal performance curves to vary over species’ distributions. However, intraspecific variation within marine species has received relatively little attention due to the belief that marine systems lack dispersal barriers strong enough to promote locally adapted traits, however, many species and populations have high levels of self-recruitment. Here we show that intraspecific variation is present among low- and high-latitude populations of a coral reef damselfish (Acanthochromis polyacanthus). Co-gradient variation was observed when examining aerobic physiology across a thermal gradient that reflected mean summer temperatures of high- and low-latitude regions, as well as projected future ocean temperatures (i.e., 27, 28.5, 30, 31.5°C). However, not all traits displayed intraspecific 53 variation; no significant differences were observed between high- and low-latitude regions when measuring immunocompetence, hematocrit, and enzyme activity. The presence of co-gradient variation suggests that dispersal limitations in marine systems can promote local adaptive responses, however, intraspecific variation may not be ubiquitous among traits. Locally adapted traits warrant consideration regarding the impact they may have on modelling population (and species) responses to climate change, identifying potential regions that may illicit sufficient adaptive response, as well as identifying the divergence or convergence traits between population
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Molecular Response of the Brain to Cross-Generational Warming in a Coral Reef Fish
Ocean warming is a threat to marine biodiversity, as it can push marine species beyond their physiological limits. Detrimental effects can occur when marine poikilotherms are exposed to conditions beyond their thermal optima. However, acclamatory mechanisms, such as plasticity, may enable compensation of detrimental effects if warming is experienced during development or across generations. Studies evaluating the molecular responses of fishes to warming have mostly focused on liver, muscle, and gonads, and little is known about the effects on other vital organs, including the brain. This study evaluated the transcriptional program of the brain in the coral reef fish Acanthochromis polyacanthus, exposed to two different warming scenarios: +1.5◦C and +3.0◦C, across successive generations. Fish were exposed to these conditions in both developmental (F1 and F2) and transgenerational settings (F2 only), as well as a treatment with step-wise warming between generations. The largest differences in gene expression were between individuals of the first and second generation, a pattern that was corroborated by pairwise comparisons between Control F1 and Control F2 (7,500 DEGs) fish. This large difference could be associated with parental effects, as parents of the F1 generation were collected from the wild, whereas parents of the F2 generation were reared in captivity. A general response to warming was observed at both temperatures and in developmental and transgenerational treatments included protein folding, oxygen transport (i.e., myoglobin), apoptosis and cell death, modification of cellular structure, mitochondrial activity, immunity and changes in circadian regulation. Treatments at the highest temperature showed a reduction in synaptic activity and neurotransmission, which matches previous behavioral observations in coral reef fishes. The Transgenerational +3.0◦C treatment showed significant activation of the gene pls3, which is known for the development of neuro-muscular junctions under heat-stress. F2 samples exposed to step-wise warming showed an intermediate response, with few differentially expressed genes compared to developmental and transgenerational groups (except for Transgenerational +1.5◦C). In combination with previous studies on liver gene expression, this study indicates that warming produces a molecular signature of stress response in A. polyacanthus that is influenced both by the intensity of warming as well as the duration of exposure
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Past research
Improving diet assessment of Arctic terrestrial predators with the size of rodent mandibles
Predator-prey interactions can control population fluctuations of several terrestrial vertebrates and energy fluxes in food webs. Quantifying these interactions typically requires the number of prey consumed by predators to be known but prey size is often ignored. We hypothesised that rodent mandibles, which are routinely found in predatory bird pellets and mammalian scats, could be used to accurately determine prey size and thus estimate biomass consumed by predators. We used 1 863 lemmings and voles from museum and field specimens collected across the North American Arctic to relate three measurements of the dentary bone and one on the molar toothrow with individual body mass. When species and location of specimens are known, our results suggest that the body mass of small rodents can be estimated with high precision using the dentary bone measurements (average R² ranging from 0.73 to 0.81), especially for lemmings and Microtus voles. Body mass can also be estimated with reasonable precision using the dentary bone measurements even when species or location was unknown (0.71 ≤ R² ≤ 0.80). Equations to convert mandible size to body mass are provided for site- and species-specific estimations. Geographic variations in the relationship between mandible size and body mass were found, suggesting potential effects of genetic isolation or interactions with the immediate environment on size. Using mandible measurements in prey remains allows more precise estimation of biomass consumed by predators, which is essential to quantify energy fluxes within ecosystems and examine resource partitioning among Arctic predators.
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Effects of the captive and wild environment on the diversity of the gut microbiome of deer mice (Peromyscus maniculatus)The term 'microbiome' refers to ecosystems entirely made up of microbial species, often inhabiting zones within our own body. Intense focus has been placed on the gut microbiome due to its ability to cross communicate with host immune systems. Current research has detected significant differences between the gut microbiome composition of different species when raised in captivity versus the wild. My research determined that mice in the wild had higher levels of gut microbiome diversity than mice in captivity. In particular microbial families Ruminococcaceae, Helicobacteraceae, and some Lachnospiraceae species were associated with exposure to the natural environment. |
Orange Mites...
For a number of years researchers at the Algonquin Wildlife Research Station have observed the presence of an orange parasite targeting the ears and genitals of various small mammals including, deer mice (Peromyscus maniculatus), red-backed voles (Myodes gapperi), Woodland jumping mice (Napaeozapus insignis), Eastern Chipmunks (Tamias striatus) and North American Red Squirrels (Tamiasciurus hudsonicus). Only recently have these orange parasites been studied in detail. Samples of the orange parasites collected in the field were placed under a microscope and identified as chiggers, belonging to the family Trombiculidae. Evidence was also found to suggest that these chiggers are associated with lower body condition in North American Red Squirrels.
I am currently part of a research project looking to learn more about how these orange parasites interact with small mammal hosts, collaborating with researchers at the University of Alberta and Laurentian University. |
Undergraduate research
Using GIS to assess the vulnerability of the boreal forest in Canada to Mountain Pine Beetle (Dendroctonus ponderosae) infestation
This semester long research project attempted to assess the vulnerability of Canada's boreal forest to infestation from the mountain pine beetle (Dendroctonus ponderosaei, MPB) over a course of twenty years under three different climate change scenarios predicted by the IPCC. All the data used for this project was gathered from open (free) sources, the data was then used to create a model simulating changes in climatic conditions under different climate change scenarios. However, the results were not able to provide a true determination of the risk Canada's boreal forest to future MPB infestations, since there was no data available that could represent winter temperatures within trees, where the MPB spend their winters. Thus the use of winter air temperatures was though to be to harsh in determining MPB survivability during the winter months.
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