Unprecedented data for estimating the carbon budget of the Arctic Ocean

The contribution of algae that grow on the seabed of the Arctic Ocean to its carbon budget has been quantified for the first time. The work carried out by Sentinel North researchers and their international partners is a major step towards refining models for predicting the fluxes of greenhouse gases in both the Arctic and across the globe. 

From insignificant input to notable contribution

Oceans regulate climate by capturing atmospheric carbon and converting it into biomass through primary production. Until very recently, this production in the Arctic Ocean was attributed almost exclusively to phytoplankton and microscopic algae found beneath sea ice. However, unprecedented data now show that seabed algae, which cover over 3 million km² in Arctic coastal areas, also play an important role. It appears that these organisms are responsible for capturing 77 billion kilograms of carbon per year, which is the equivalent of 20% to 35% of the annual primary production by the phytoplankton in this same region.

To measure the carbon capture of seabed algae, the normal sampling methods had to be reviewed. As conventional oceanic research vessels are too large to venture close to the shore, the scientists had to resort to smaller boats and scuba diving to photograph and sample the species that inhabit the area. Combined with satellite images and a new mathematical model, these observations have now made it possible to estimate the contribution of algae in coastal areas to the carbon budget of the Arctic Ocean.

This scientific breakthrough is the fruit of a joint effort involving some twenty scientists from nine countries. In pooling their data on the abundance and distribution of seabed algae, they were able to provide the first portrait of the carbon capture of these organisms in the Arctic Ocean. This unprecedented work even earned the team a place among the 2024 top 10 discoveries of the year compiled by the magazine Québec Science.

What does the future hold for seabed algae?

At a time when the role of seabed algae in the carbon budget of the Arctic Ocean has only just been discovered, the upcoming changes in the climate of this ecosystem could muddy the waters. On the one hand, the shrinking Arctic sea ice will likely increase the surface area of the seafloor exposed to light that could be inhabited by algae. On the other, the thawing of the coastline increases erosion and the amount of sediments found in the ocean, blocking out light and undermining primary production. In this changing context, monitoring the contribution of seabed algae to the carbon budget of the Arctic Ocean, and consequently that of our planet as a whole, is all the more important.

Header photo: Ignacio Garrido