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- Département de biologie
- Canada Research Chairs
- Québec-Océan Pavillon Alexandre-Vachon
- Québec
- G1K 7P4
- Canada
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Research Profile
Research Interests
My research domain is biological oceanography. I am more specifically interested by the biological production of the climate-active trace gas dimethylsulfide (DMS) and its impact on climate. My work includes laboratory experiments on the physiological control of algal DMS production, oceanographic cruises in the North Atlantic and North Pacific aiming at understanding the dynamics of DMS in these productive waters, and the development of a mechanistic model of ocean DMS production (Northern Oceans DMS Emission Model – NODEM). I was involved in two large scale iron fertilisation experiment (SERIES and SEEDS II) where I investigated the impact of iron on DMS production. My present work is taking place in the Canadian Arctic where I am quantifying the effect of global change on DMS and nitrous oxide production. I am also working on the impact of climate change on the ecology harmful algal blooms.
Current projects
1. Arctic SOLAS (International Polar Year and OASIS programs)
Summary - Surface temperatures are rising at a rate unprecedented in recorded human history and the patterns of change during recent decades strongly point to increased anthropogenic emissions of carbon dioxide (CO2) and other greenhouse gases as the dominant factor. The Arctic is particularly sensitive to this warming. The Canadian Arctic is changing with important reduction of the extent, thickness, and age of sea ice and an increased eastward flow of Pacific waters through the Canadian Archipelago. The influence of these major alterations of the Arctic on sea-air and ice-air flux of climate-active gases and aerosols, and on atmospheric chemistry and radiative properties are largely unknown. The Arctic is important in the production and cycling of climate-active gases, including CO2, carbon monoxide (CO), nitrous oxide (N2O), volatile organic compounds (VOCs), halocarbons, and dimethylsulfide (DMS). The production of these gases is likely to be affected by changes in sea ice cover and thickness, and their concentration and fate in the atmosphere are likely to be affected by changing emissions from the ocean and by changing atmospheric dynamics in a warming Arctic. These potential feedbacks have not been examined in depth. The processes involved are at present poorly characterized and it is impossible to specify the sign (positive or negative), or magnitude of the gas feedbacks resulting from climate-driven changes in Arctic sea ice and circulation. It is the goal of this program to provide critical knowledge on the interactions between sea ice, circulation and emissions of gases and particles in the Arctic and to help reduce uncertainties as to these climate processes. We will seek answers to these key questions: 1) How will the increased outflow of Pacific waters through the Canadian Archipelago affect the production and emission of climatically active gases? 2) How do ice properties influence the production and ice-atmosphere exchanges of climatically active trace gases? 3) How do these alterations in ocean-ice-atmosphere exchanges influence the chemical and radiative properties of the Arctic atmosphere? These questions will be addressed during two expeditions on the Canadian research ice-breaker Amundsen in the Eastern Canadian Arctic in the fall of the International Polar Year (IPY) 2007-08.
2. Biological cycling of DMS(P) in the HNLC waters of the Northeast Pacific
Summary – The bacterial cycling of DMS(P) is quantified along Line P, a section extending from the Fe-rich Canadian west coast to the Fe-depleted waters of the Alaska Gyre (Ocean Station Papa). This region is known for it’s extremely high (> 15 nM) concentrations of DMS. My objective is to discover the mechanisms responsible for these high DMS production rates. The project is linked to the Line P cruise program conducted by the Institute of Ocean Sciences of the Department of Fisheries and Oceans Canada (Sydney, Canada). I am presently working on a new program which will include the collection and chemical characterisation of Asian dust and its utilisation during onboard, low-volume incubation experiments to be conducted along Line P.
