Acceleration of ocean warming, salinification, deoxygenation and acidification in the surface subtropical North Atlantic Ocean

• Published in: Communications Earth & Environment
• Main Authors: Bates, Nicholas Robert, Johnson, Rodney J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2020
• Subjects: General Earth and Planetary Sciences; General Environmental Science; North Atlantic; Ocean acidification
• Online Access: http://dx.doi.org/10.1038/s43247-020-00030-5; https://www.nature.com/articles/s43247-020-00030-5.pdf; https://www.nature.com/articles/s43247-020-00030-5

Abstract Ocean chemical and physical conditions are changing. Here we show decadal variability and recent acceleration of surface warming, salinification, deoxygenation, carbon dioxide (CO 2 ) and acidification in the subtropical North Atlantic Ocean (Bermuda Atlantic Time-series Study site; 1980s to present). Surface temperatures and salinity exhibited interdecadal variability, increased by ~0.85 °C (with recent warming of 1.2 °C) and 0.12, respectively, while dissolved oxygen levels decreased by ~8% (~2% per decade). Concurrently, seawater DIC, f CO 2 (fugacity of CO 2 ) and anthropogenic CO 2 increased by ~8%, 22%, and 72% respectively. The winter versus summer f CO 2 difference increased by 4 to 8 µatm decade −1 due to seasonally divergent thermal and alkalinity changes. Ocean pH declined by 0.07 (~17% increase in acidity) and other acidification indicators by ~10%. Over the past nearly forty years, the highest increase in ocean CO 2 and ocean acidification occurred during decades of weakest atmospheric CO 2 growth and vice versa.