Annie Bourbonnais, PhD Candidate

I pursued a master's degree in oceanography at the GEOTOP research center (center for research in Geochemistry and Geodynamics) at the University of Quebec in Montreal. The goal of my master's thesis was to study Nitrogen (N) cycle processes in the Azores Front region (Atlantic Ocean) using stable isotopes of nitrate and dissolved organic N. The results obtained from my work yielded clear insights into the importance of nitrogen fixation in the Northeast Atlantic.

I moved to Victoria (BC) in fall 2007 to start a PhD at UVic. My research is focused on the N cycle and the related microbial community in subsurface hydrothermal vent systems of the Juan de Fuca Ridge in the Northeast Pacific Ocean. Nitrogen is an essential building block of proteins, and is therefore an essential macronutrient for all organisms. A better understanding of bacterially-mediated N-cycle dynamics is critical to better constrain metabolic processes taking place in the subsurface biosphere of hydrothermal vent systems. My research applies a combination of biogeochemical and molecular biology methods to vent fluids sampled by submersible vehicles. I mostly focus on reactions removing fixed N, i.e. denitrification (the conversion of nitrate into N2 gas) and anaerobic ammonium oxidation (anammox, the conversion of nitrite and ammonium into N2 gas) in hydrothermal vent fluids. Oceanic N sinks that remove bio- available N ultimately affect chemosynthetic primary productivity in these ecosystems.

During my Ph. D, I have also been responsible for organizing nine research cruises in Saanich inlet, a British Columbia fjord, onboard the R/V Strickland Victoria, between April 2008 to April 2009. Saanich Inlet is an ideal environment to study N-cycle processes, because of periodic renewal events during the spring and fall that re-supply oxygen to otherwise anoxic bottom waters. The annual variation in deep water dissolved oxygen concentrations in the Saanich Inlet allows the effect of different oxygenation regimes on the nitrogen cycle in a deep water system to be observed. I am mostly interested about temporal changes in water-column versus sedimentary denitrification using the N isotopic composition of dissolved inorganic nitrogen.

When I am not busy with my research, I enjoy outdoor activities (sailing, rock climbing, hiking and skiing).

Publications

Somes, C, A. Schmittner, E. D. Galbraith, M. F. Lehmann, M. A. Altabet, J. P. Montoya, R. M. Letelier, A. C. Mix, A. Bourbonnais, and M. Eby. (2010) Simulating the global distribution of nitrogen isotopes in the Ocean, Global Biogeochemical Cycles, doi: 10.1029/2009GB003767, in press (accepted 21 July 2010).

Manning, C. C, R. C. Hamme, and A. Bourbonnais. (2010) Impact of deep-water renewal events on fixed nitrogen loss from seasonally-anoxic Saanich Inlet, Marine Chemistry, 122(1-4), 1-10, doi:10.1016/j.marchem.2010.08.002.

Bourbonnais, A., M. F. Lehmann, J. J. Waniek and D. E. Schultz-Bull. (2009) Nitrate isotope anomalies as indicator of N2 fixation in the Azores Front region (subtropical N-E Atlantic), Journal of geophysical Research, 114, C03003, doi:1029/2007JC004617.

Clark, I.D., R. Timlin, A. Bourbonnais, K. Jones, and K. Wickens. (2008) Origin and fate of industrial ammonia in municipal groundwaters – tracing anaerobic oxidation (anammox) and apportionment with 15N-NH4, Ground Water Monitoring and Remediation, 28, 73-82.

Contact me at annieb@uvic.ca

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