US EPA

4154627 

Journal Article 

Redox reactions and weak buffering capacity lead to acidification in the Chesapeake Bay 

Cai, WJ; Huang, WJ; Luther, GW; Pierrot, D; Li, M; Testa, J; Xue, M; Joesoef, A; Mann, R; Brodeur, J; Xu, YY; Chen, B; Hussain, N; Waldbusser, GG; Cornwell, J; Kemp, WM 

2017 

1 

Nature Communications
EISSN: 2041-1723 

8 

1 

Article #369 

English 

28848240 

10.1038/s41467-017-00417-7 

WOS:000408440700006 

is supplemented by 4154628 : Supplementary materials

The combined effects of anthropogenic and biological CO2 inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H2S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. We show that a pH minimum occurs in mid-depths where acids are generated as a result of H2S oxidation in waters mixed upward from the anoxic depths. Our analyses also suggest a large synergistic effect from river-ocean mixing, global and local atmospheric CO2 uptake, and CO2 and acid production from respiration and other redox reactions. Together they lead to a poor acid buffering capacity, severe acidification and increased carbonate mineral dissolution in the USA's largest estuary.