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As the permafrost melts, the amount of dissolved organic carbon in the ocean could be multiplied. To further understand this process, an oceanography student spent the summer in the Northwest Territories, witnessing the effects of climate change in real time at the same time.
Under an overhanging cliff, Aude Flamand hits with a pickaxe to sample pieces of ice. Then, she installs a bucket under the ground which melts drop by drop. But after 12 hours of collecting, the cliff collapses, destroying the precious loot. Luckily, the chemist was not below.
With climate change, the landscape is changing rapidly in the Canadian Arctic. To the point of sometimes sabotaging scientific samples in the space of a few days or hours. Aude Flamand learned it the hard way during her stay in the Northwest Territories this summer, as part of her master’s degree in oceanography at the Institut des sciences de la mer de Rimouski (ISMER). The student returned empty-handed from a multi-day scientific expedition by boat. She hoped to sample some coastal cliffs where permafrost is exposed – that layer of soil permanently frozen for at least two years. At the scene, a large amount of permafrost had melted, creating a pool of clay at the foot of the cliffs preventing any advance on foot or by boat – her colleague even lost a boot there forever. As the North is transforming at high speed, the student has embarked on this race against time, set in motion to collect data and educate the world on what is happening.
The fate of permafrost in the oceans
On the thermometer that day, it was 28 ° C. Drops of water and pieces of mud trickle down a large block of clay. On his blog A chemist in the arctic, Aude Flamand indicates the rate of thawing of permafrost. But it is near the sea that this phenomenon, concomitant with erosion, is most spectacular. The student specifies that the coastline can retreat 1.8 meters per year in the Tuktoyaktuk region, and lose up to 30 meters annually in certain sectors of the Beaufort Sea.
“It’s spectacular to see the cliffs engulfed by the ocean and the permafrost melt away,” exclaims Mr.me Flemish. The latter is interested in the consequences of melting permafrost on water chemistry, which can generate cascading effects on ecosystems and the gases emitted into the atmosphere.
When it melts, permafrost releases large amounts of dissolved organic material. “This dissolved organic matter (MOD) has the effect of increasing the turbidity of the water,” explains the student. “If photosynthetic organisms like plankton and algae don’t have access to light, they can’t photosynthesize. This means that there will be less oxygen production and that we will have areas poorer in biodiversity. This MOD can also, by entering into geochemical cycles such as the carbon cycle, release more greenhouse gases into the atmosphere.
“In permafrost, we do not know exactly what this MOD is made of and how it reacts when it is released”, continues the chemist. The student’s project aims in particular to identify the signature of the dissolved organic carbon present in this material and to follow the path of this element in the environment. Is carbon dissolved in water or is it sequestered in sediment? To find out, Aude Flamand has collected more than 150 samples, which she will analyze in the laboratory this winter.
A human experience
Departure from Montreal, stopover in Edmonton, two-week quarantine in Yellowknife, flight to Inuvik, transport by car to Tuktoyaktuk, a small Inuvialuit community sitting on the 69e parallel. Going to Canada’s North is like going to the end of the world and gaining new perspectives. “In Quebec, global warming, we do not see it, it does not affect our daily life, or very little,” observes Aude Flamand, who says she was welcomed with open arms by the community. “When we are there, we see it, we hear the testimonies of the community, which is on the front line. The coast is being eaten by the ocean, but people don’t want to be moved. The water is less salty in the bay, so there are less herring, which the community used to eat, and there are more freshwater fish. “
In Quebec, global warming, we do not see it, it does not affect our daily life, or very little
The Aude Flamand project could also have an interest in the health of the inhabitants of Tuktoyaktuk. Organic matter dissolved in these waters can more easily capture heavy metals and pollutants, she explains. Could thawing permafrost affect the quality of the water supply to local communities?
“I used to do science in my laboratory,” continues the enthusiast. “It showed me the side fun and social science. It showed me that I was in the right field and that it is important for me to communicate what I do, especially with the community. ”
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