ADVANCING ECOTOXICOLOGY, FOOD SCIENCE, WILDLIFE ECOLOGY, SOIL BIOGEOCHEMISTRY, AND MICROBIAL ECOLOGY USING COMPOUND-SPECIFIC CARBON AND NITROGEN ISOTOPES ANALYSIS

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Our research team aims to understand the movement and fate of energy, nutrients, and contaminants through natural ecosystems and human-managed food systems, from microbes to top predators, using chemical tracers. A major recent advance in this approach is compound-specific isotopes analysis (CSIA), e.g., amino acid isotopes analysis and fatty acid isotopes analysis. We are seeking RTI funds for the equipment needed for CSIA: a gas-chromatograph interfaced to an isotope ratio mass spectrometer (GC-IRMS). This system will provide crucial new high-resolution tracer data accelerating the research programs of Melissa McKinney, Nil Basu, Stephane Bayen, Jessica Head, Kyle Elliott, Cynthia Kallenbach, Denis Roy, and Lyle Whyte. ******The CSIA approach shows potential to be a valuable tool in tracer applications, which have traditionally relied on bulk isotopes analysis. For example, as nitrogen isotope ratios of certain amino acids are conserved through the food web, while others show trophic enrichment, amino acid isotopes analysis has been shown to provide a better indication of trophic position than bulk nitrogen isotopes. With the GC-IRMS, our research groups will lead the development and application of cutting-edge CSIA techniques to identify and quantify pathways and changes in agricultural and natural ecosystems across multiple taxonomic, spatial, and temporal scales.******The GC-IRMS represents a key component of multiple research groups within the Faculty of Agricultural and Environmental Sciences at McGill University. McKinney, Basu, and Head will use the GC-IRMS to generate new high-resolution data fostering critical advances in understanding intra-specific, inter-specific, spatial, and temporal variation in contaminant exposures. Bayen will use the GC-IRMS to assess food origin fraud. Elliott will use the system to examine food web structures and their associations with contaminants. Kallenbach will use it to understand how global change factors, e.g., warming, flooding, agricultural management, influence soil nitrogen dynamics. Roy proposes to use it to assess diet differences in Arctic marine fish species adapted to different marine habitats across Canadian Arctic basins. Whyte will use the GC-IMRS to identify and track shifts in amino acid and fatty acid isotopes in polar microbial strains growing at different temperatures and salinities to determine microbial adaptations of microorganisms living in cryoenvironments.******Our 20 or more students will have a clear competitive advantage with hands-on skills in this state-of-the-science system, including its use, maintenance, quality assurance/quality control, and in isotope data processing. More broadly, various scientific fields in Canada employ GC and MS as analytical tools; thus, such hands-on training provides marketable skills for students to succeed in future academic, government, industry, and non-profit careers across the agricultural and environmental sciences.*****