A multi‐decadal delay in the onset of corrosive ‘acidified’ waters in the Ross Sea of Antarctica due to strong air‐sea CO2 disequilibrium

Abstract

Antarctic coastal waters have an abundance of marine organisms that secrete the mineral aragonite for growth and survival. Increasing oceanic anthropogenic CO2 uptake will push these waters to a point whereby aragonite will start to geochemically corrode, with direct consequences for the Antarctic ecosystem. Here we combine surface CO2 data in the Ross Sea, Antarctica with a regional ocean/sea‐ice model to better pinpoint the timing of corrosive conditions. Our analysis suggests sea‐ice cover and deep‐water entrainment during winter results in 65% lower storage of anthropogenic CO2 in comparison to atmospheric CO2 equilibrium. This means that instead of corrosive ‘acidified’ waters beginning as early as the winter of 2015, anthropogenic CO2 disequilibrium delays its onset by up to 30 years, giving this Antarctic marine ecosystem a several decade reprieve to corrosive conditions. Our results demonstrate a broader importance of understanding natural oceanic carbon cycle variability for the onset of corrosive conditions.