Anthropogenic CO2 and ocean acidification in Argentine Basin Water Masses over almost five decades of observations

Ocean Acidification and Long‐Term Changes in the Carbonate System Properties of the South Atlantic Ocean

“…(2020) we found that under the SSP2‐4.5 the AAIW will become unsaturated in aragonite in ∼30 years (Figure S11 in Supporting Information S1), in line with the predictions of Fontela et al. (2021). This time will be even shorter along the African coast, where aragonite unsaturation is expected in the next 10–20 years (Figure S11 in Supporting Information S1).…”

“…For the SACW, a total unsaturation with respect to aragonite only was observed for the emissions projected under the SSP5‐8.5 in the year 2060, close to the estimates of Fontela et al. (2021) for the Argentine Basin. However, while useful, these projections do not take into account the possible changes that may occur in the biological pump and the ocean circulation, highlighting that a model‐based projection such as the one carried out by Fransner et al.…”

“…A column inventory change of 0.94 ± 0.39 mol C m −2 yr −1 was found from the surface down to 2000 m. This C ant uptake was the major process responsible for the acidification of the upper part of the water column, and rates of −0.0020 ± 0.0007 and −0.0009 ± 0.0009 pH units yr −1 were observed in central and intermediate waters, respectively. Under these conditions, it is expected that the AAIW will become unsaturated in aragonite in ∼30 years under the emissions projected in the SSP2‐4.5, in line with previous previsions (e.g., Fontela et al., 2021; Salt et al., 2015).…”

“…(2015) and Fontela et al. (2021) along the A17 section, but our results show that a similar feature can also be found along the eastern margin. However, as the available data in this region is scarce, and has a low temporal resolution, new observations are necessary to constrain this effect during the 2010s decade.…”

“…(2016) for the AAIW between 1960 and 2015 in the South Atlantic subtropical gyre (−0.18 ± 0.04 μmol kg −1 yr −1 ) and the AOU rate of Fontela et al. (2021) in the Argentine Basin (0.38 ± 0.13 μmol kg −1 yr −1 ). Furthermore, this result is in line with the observed AAIW deoxygenation found by Schmidtko et al.…”