Immediate and long-lasting impacts of the Mt. Pinatubo eruption on ocean oxygen and carbon inventories

Abstract

As a result of anthropogenic activities, the global ocean is losing oxygen and gaining carbon. Observations indicate that the ocean's oxygen inventory has declined by about 2% in the 5 decades following 1960 as the upper ocean warms and stratifies (Ito et al., 2017;Schmidtko et al., 2017). This oxygen loss has major consequences for nutrient cycling, compression of marine ecosystem habitats, and global fisheries (Deutsch et al., 2015;Gruber, 2011;Keeling et al., 2010). Since pre-industrial times, the ocean has absorbed ∼170 Pg of anthropogenic carbon from the atmosphere (Canadell et al., 2021), which is beneficial for the mitigation of anthropogenic warming, but harmful to some organisms through the related decline in pH, known as ocean acidification.These long-term changes in ocean oxygen and carbon are superimposed on large interannual to multi-decadal variability, challenging the attribution of reported trends (