Ocean Acidification trends and Carbonate System dynamics in the North Atlantic Subpolar Gyre during 2009–2019

• Main Authors: Curbelo-Hernández, David, Pérez, Fiz F., González-Dávila, Melchor, Gladyshev, Sergey V., González, Aridane G., González-Santana, David, Velo, Antón, Sokov, Alexey, Santana-Casiano, J. Magdalena
• Format: Text
• Language: English
• Published: 2024
• Subjects: Iceland; North Atlantic; Ocean acidification
• Online Access: https://doi.org/10.5194/egusphere-2024-1388; https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1388/

The CO 2 -carbonate system dynamics in the North Atlantic Subpolar Gyre (NASPG) were evaluated between 2009 and 2019. Data was collected aboard eight summer cruises through the CLIVAR 59.5º N section. The Ocean Acidification (OA) patterns and the reduction in the saturation state of calcite ( Ω Ca ) and aragonite ( Ω Arag ) in response to the increasing anthropogenic CO 2 ( C ant ) were assessed within the Irminger, Iceland and Rockall basins during a poorly-assessed decade in which the physical patterns reversed in comparison with previous well-known periods. The observed cooling, freshening and enhanced ventilation increased the interannual rate of accumulation of C ant in the interior ocean by 50–86 % and the OA rates by close to 10 %. The OA trends were 0.0013–0.0032 units yr -1 in the Irminger and Iceland basin and 0.0006–0.0024 units yr -1 in the Rockall Trough, causing a decline in Ω Ca and Ω Arag of 0.004–0.021 and 0.003–0.0013 units yr -1 , respectively. The C ant -driven rise in total inorganic carbon ( C T ) was the main driver of the OA (contributed by 53–68 % in upper layers and >82 % toward the interior ocean) and the reduction in Ω Ca and Ω Arag (>64 %). The transient decrease in temperature, salinity and A T collectively counteracts the C T -driven acidification by 45–85 % in the upper layers and in the shallow Rockall Trough and by <10 % in the interior ocean. The present investigation reports the acceleration of the OA within the NASPG and expands knowledge about the future state of the ocean.