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Les systèmes terrestres
Projets de recherche en cours (2019-2023)
Nunataryuk – Permafrost thaw and the changing Arctic coast: the MacKenzie delta and coastal waters sampling
Global warming is affecting a broad spectrum of marine and terrestrial environments in high northern latitudes. In the Arctic ocean, sea ice area has been shrinking over the last three decades. What is particularly important here is that the area of open water resulting from the sea ice melt is a potentially important sink for atmospheric CO2, simply because colder water temperature can dissolve more atmospheric gases. Because CO2 is a greenhouse gas, an increase in the concentration in the atmosphere contributes to an increase in air temperature, one of our major concerns.
On land, this warming further induces thawing of the permafrost, which contains a huge amount of old organic carbon. Arctic soil organic carbon accounts for over 50% of global soil carbon and is roughly twice the amount present in the atmosphere. An increasing amount of the newly mobilized old organic carbon originating from permafrost thaw is expected to be delivered to the Arctic Ocean by rivers and probably through groundwater discharges along the huge Arctic coastline. Recent findings showed that the ancient permafrost-origin carbon is highly reactive and thus can be rapidly utilized by microorganisms, meaning a possible source of CO2 released back to the atmosphere.
Here is an important question: will the coastal Arctic Ocean be a net sink or source of CO2 in the near future? To answer this important question, we will conduct extensive field observations in the delta of the Mackenzie and the Southern Beaufort Sea where the Mackenzie river influence is significant, the Mackenzie river being the second largest river of North America. The project will provide the first quantitative assessment that includes the role of permafrost carbon and groundwaters, which might be considered for stakeholders.