My research interests broadly center on cardiovascular responses to physiological and abiotic stress. I use a comparative approach to look for commonalities in how cardiovascular systems in animals that inhabit heterogeneous environments overcome physiological and abiotic stress. By conducting research on a phylogenetically diverse number of fish species (including agnathans, chondrichthyans and teleosts), and mammals I have discovered various metabolic, functional, and morphological phenotypes that affect species sensitivity or persistence in the face of anoxia, temperature variation, pollution, and disease. The unifying goal of my research is to make fundamental discoveries on cardiovascular function and apply them to further our understanding of species’ underlying physiology. Past and present research topics:
My approach to obtaining data blends the functional understanding that comes from basic comparative physiology with the fields of conservation, toxicology, and evolutionary biology. Previously, my research focused on the relationship between cardiovascular physiology and organismal function using a diverse number of elasmobranch species. By exploring inter-and intra- species variation in cardiovascular variables I discovered a mechanism that allows adequate oxygen to be delivered to the heart during times of extreme physiological stress. The discovery of this mechanism allowed me to detect similarities with mammalian cardiovascular function and identify possible underlying mechanisms that may be present in vertebrates in general. Furthermore, my morphological analysis of the coronary circulation across shark taxa using classical corrosion casting, histological techniques, and 3D imaging of vascular beds combined with phylogenetic analysis and basic fluid dynamics led me to discover that temperature plays a role as a selective pressure on the design of vascular beds.
During my first postdoc I expanded my work to investigate whether phenotypic plasticity allow species to overcome anthropogenic sources of environmental pollution in the form of polycyclic aromatic hydrocarbons (PAHs -the toxic components of oil) that would otherwise be lethal. As part of the RECOVER consortium I was able to collaborate with geneticists, aquacultural scientists, developmental biologists, physiologists, and toxicologists to tackle the question of how fish species respond to PAH exposure on multiple levels of biological organization.
During a post doctoral research position at the University of Pennsylvania I utilized gene knockout and inducible gene knockout models to investigate how specific cell signaling pathways can lead to disease states, such as cardiomyopathy, cardiac conduction disease, and sudden cardiac death in mammalian models. Working with biomedical models has allowed me to expand my skillset to include genetic sequencing and these are valuable tools when considering the diverse responses of the cardiovascular system to environmental changes across species of ectothermic animals.
I was previously at in the Department of Integrative Biology at the University of Guelph in Todd Gillis' lab https://comparativephys.ca/gillislab/ where I investigated the spectacular anoxia tolerance of a phylogenetically ancient species of hagfish. I have previously discovered a number of diverse cardiovascular and biochemical phenotypes that permitted survival of these fish for >36h of complete oxygen deprivation in the Farrell lab at the University of British Columbia (UBC). These discoveries provided new insight into cardiovascular function that has been traditionally viewed as a highly aerobic process. Currently I am expanding on discoveries made in the Gillis lab that indicate hagfish a use atypical biochemical pathways to ensure their anoxic survival - stay tuned.
Postdoctoral Scholar, 2018 to current
University of Guelph
Postdoctoral Scholar, 2017 to 2018
University of Pennsylvania, Perelmen School of Medicine, Department of Pharmacology
Postdoctoral Scholar, 2015 to 2017
University of Miami's Rosenstiel School of Marine and Atmospheric Science
PhD in Zoology/Animal Biology, 2015
University of British Columbia
MSc in Comparative Physiology, 2010
University of British Columbia
BSc in Biology, 2006
University of New Brunswick
Aqueous crude oil spills expose fish to varying concentrations of dissolved polycyclic aromatic hydrocarbons (PAHs), which can have lethal and sublethal effects. The heart is particularly vulnerable in early life stages, as PAH toxicity causes developmental cardiac abnormalities and impaired cardiovascular function. However, cardiac responses of juvenile and adult fish to acute oil exposure remain poorly understood. We sought to assess cardiac function in a pelagic fish species, the cobia (Rachycentron canadum), following acute (24 h) exposure to two ecologically relevant levels of dissolved PAHs. Cardiac power output (CPO) was used to quantify cardiovascular performance using an in situ heart preparation. Cardiovascular performance was varied using multiple concentrations of the β-adrenoceptor agonist isoproterenol (ISO) and by varying afterload pressures. Oil exposure adversely affected CPO with control fish achieving maximum CPO’s (4 mW g-1 Mv) greater than that of oil-exposed fish (1 mW g-1 Mv) at ISO concentrations of 1 × 10-6 M. However, the highest concentration of ISO (1 × 10-5 M) rescued cardiac function. This indicates an interactive effect between oil-exposure and β-adrenergic stimulation and suggests if animals achieve very large increases in β-adrenergic stimulation it could play a compensatory role that may mitigate some adverse effects of oil-exposure in vivo.