Current DateSeptember 19, 2021

The increasing acidification of the Arctic Ocean worries scientists

According to a new study, the acidification of the Arctic Ocean over the century will be greater than expected. As a result, the adaptation of marine life is less obvious than one might think. About 30% of the carbon dioxide (CO2) released by human activities is absorbed by the ocean. This process effectively limits the magnitude of the climatic disturbance linked to anthropogenic greenhouse gas emissions. However, it also causes acidification of water, the deleterious effects of which on the living are no longer to be demonstrated.

Due to its low horizons of saturation in aragonite and calcite, the Arctic is the area most affected by this phenomenon. However, according to new work, the amount of CO2 absorbed by the basin over the century promises to be greater than previously thought. Also, its acidification has been revised upwards – with strong implications for the regional ecosystem.

So far, models have shown notable divergence in the extent of CO2 capture by Arctic waters. Using observational data, the scientists were nevertheless able to show that the most realistic models were those with the highest absorptions. They correspond to a higher capacity for deep water formation and are associated with an increased transport of CO2 from the surface to the interior of the ocean.

Thus, by considering the bias of certain models, it was possible to reduce the uncertainty on future projections. The average scenario is now found above its median value before correction of the bias. More specifically, carbon capture has been revised upwards by around 20%. “Our results suggest that it will be more difficult than expected for arctic organisms to adapt to ocean acidification,” said Lester Kwiatkowski, one of the co-authors of the paper.

“This leads to considerably enhanced acidification, particularly between 200 and 1000 meters deep,” explains Jens Terhaar, lead author of the study. “This depth range is an important refuge area for many marine organisms”.

It will be recalled that more acidic water mainly affects calcifying organisms. Indeed, the latter end up no longer being able to form their calcareous skeleton. This is the case, for example, with corals, molluscs, sea urchins and even starfish. Ultimately, the entire marine food web ends up being affected. In the Arctic, living things are also facing global warming twice as fast as the world average. Recently, a temperature of 38 ° C was recorded in this respect beyond the polar circle. A record.

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