Detecting anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean

[摘要] Fossil fuel use, cement manufacture and land-use changes are the primarysources of anthropogenic carbon dioxide (CO₂) to the atmosphere, withthe ocean absorbing approximately 30% (Sabine et al., 2004). Ocean uptakeand chemical equilibration of anthropogenic CO₂ with seawater resultsin a gradual reduction in seawater pH and saturation states (Ω) forcalcium carbonate (CaCO₃) minerals in a process termed oceanacidification. Assessing the present and future impact of oceanacidification on marine ecosystems requires detection of the multi-decadalrate of change across ocean basins and at ocean time-series sites. Here, weshow the longest continuous record of ocean CO₂ changes and oceanacidification in the North Atlantic subtropical gyre near Bermuda from1983–2011. Dissolved inorganic carbon (DIC) and partial pressure of CO₂(pCO₂) increased in surface seawater by ~40 μmol kg⁻¹and ~50 μatm (~20%), respectively. Increasing Revellefactor (β) values imply that the capacity of North Atlantic surfacewaters to absorb CO₂ has also diminished. As indicators of oceanacidification, seawater pH decreased by ~0.05 (0.0017 yr⁻¹) andω values by ~7–8%. Such data provide critically neededmulti-decadal information for assessing the North Atlantic Ocean CO₂sink and the pH changes that determine marine ecosystem responses to oceanacidification.

[学科分类] 地球化学与岩石