Fontela, M., Pérez, F. F., Carracedo, L. I., Padín, X. A., Velo, A., García-Ibañez, M. I., & Lherminier, P. (2020). The Northeast Atlantic is running out of excess carbonate in the horizon of cold-water corals communities. Scientific Reports, 10 (1), 14714. https://doi.org/10.1038/s41598-020-71793-2
The oceanic uptake of atmospheric carbon dioxide (CO2) emitted by human activities alters the seawater carbonate system. The increase of atmospheric CO2 leads to an increase in ocean anthropogenic carbon (Cant) and a decrease in carbonate that is unequivocal in the upper and mid-layers (0–2,500 m depth). In the mid-layer, the carbonate content in the Northeast Atlantic is maintained by the interplay between the northward spreading of recently conveyed Mediterranean Water with excess of carbonate and the arrival of subpolar-origin waters close to carbonate undersaturation. In this study the authors examined the chemical status of the Northeast Atlantic by means of a high-quality database of carbon variables based on the GO-SHIP A25 section (1997–2018). A progression to undersaturation with respect to carbonate could compromise the conservation of the habitats and ecosystem services developed by benthic marine calcifiers inhabiting the mid-layer depth range, such as the cold-water corals (CWC) communities. The authors also stressed that for each additional ppm in atmospheric pCO2 the waters surrounding CWC communities lose carbonate at a rate of − 0.17 ± 0.02 μmol kg−1 ppm−1. The accomplishment of global climate policies to limit global warming below 1.5–2 ℃ will avoid the exhaustion of excess carbonate in the Northeast Atlantic.
Policy relevant message:
Increasing amount of atmospheric CO2 causes alterations of oceanic carbon system, which leads to destructions of cold-water corals. The accomplishment of global climate policies to limit global warming below 1.5–2 ℃ is critical to avoid further alterations of carbon system in the Northeast Atlantic.