Deep oceans may acidify faster than anticipated due to global warming. Issue 12 (December 2017)

• Record Type: Journal Article
• Authors: Chen, Chen-Tung; Lui, Hon-Kit; Hsieh, Chia-Han; Yanagi, Tetsuo; Kosugi, Naohiro; Ishii, Masao; Gong, Gwo-Ching
• Is Part Of: Nature climate change. Volume 7:Issue 12(2017)
• Page Start: 890
• Page End: 894
• Publication Date: 2017-12
• Subjects: Climatic changes -- Periodicals; 333.7205
• DOI: 10.1038/s41558-017-0003-y
• Languages: English
• ISSNs: 1758-678X

Abstract

Abstract Oceans worldwide are undergoing acidification due to the penetration of anthropogenic CO2 from the atmosphere1–4 . The rate of acidification generally diminishes with increasing depth. Yet, slowing down of the thermohaline circulation due to global warming could reduce the pH in the deep oceans, as more organic material would decompose with a longer residence time. To elucidate this process, a time-series study at a climatically sensitive region with sufficient duration and resolution is needed. Here we show that deep waters in the Sea of Japan are undergoing reduced ventilation, reducing the pH of seawater. As a result, the acidification rate near the bottom of the Sea of Japan is 27% higher than the rate at the surface, which is the same as that predicted assuming an air–sea CO2 equilibrium. This reduced ventilation may be due to global warming and, as an oceanic microcosm with its own deep- and bottom-water formations, the Sea of Japan provides an insight into how future warming might alter the deep-ocean acidification. Changes in deep-water ventilation could potentially cause acidification from organic matter breakdown. The Sea of Japan has an acidification rate 27% higher at depth than at the surface, showing how reduced ventilation from warming could impact the deep ocean.