Burger, Friedrich A.; Frölicher, Thomas L. (2023). Drivers of surface ocean acidity extremes in an Earth system model. Global biogeochemical cycles, 37(9) American Geophysical Union 10.1029/2023GB007785
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Oceanic uptake of anthropogenic carbon causes acidification, a process that describes the increase in hydrogen ion concentrations ([H+ ]) and decrease in calcium carbonate mineral saturation states (Ω). Of particular concern are ocean acidity extreme (OAX) events, which pose a significant threat to many calcifying marine organisms. However, the mechanisms driving such extreme events are not well understood. Here, we use high-frequency output from a fully-coupled Earth system model of all processes that influence the surface ocean temperature and carbon budgets and ultimately [H+] and Ω anomalies to quantify the driving mechanisms of the onset and decline of high [H+] and low Ω extreme events. We show that enhanced temperature plays a crucial role in driving [H+] extremes, with increased net ocean heat uptake being the dominant driver of the event onset in the subtropics. In the mid-to-high latitudes, decreased downward vertical diffusion and mixing of warm surface waters during summer, and increased vertical mixing with warm and carbon-rich subsurface waters during winter are the main drivers of high [H+] extreme event onset. In the tropics, increases in vertical advection of carbon-rich subsurface waters are the primary driver of the onset of high [H+ ] extremes. In contrast, low Ω extremes are driven in most regions by increases in surface carbon concentration due to increased vertical mixing with carbon-rich subsurface waters. Our study highlights the complex interplay between heat and carbon anomalies driving OAX events and provides a first foundation for more accurate prediction of their future evolution.
Item Type: |
Journal Article (Original Article) |
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Division/Institute: |
08 Faculty of Science > Physics Institute > Climate and Environmental Physics 10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR) 08 Faculty of Science > Physics Institute |
UniBE Contributor: |
Burger, Friedrich Anton, Frölicher, Thomas |
Subjects: |
500 Science > 530 Physics 500 Science > 550 Earth sciences & geology |
ISSN: |
0886-6236 |
Publisher: |
American Geophysical Union |
Funders: |
[42] Schweizerischer Nationalfonds ; [222] Horizon 2020 |
Projects: |
Projects 0 not found. Projects 820989 not found. Projects 862923 not found. |
Language: |
English |
Submitter: |
Friedrich Anton Burger |
Date Deposited: |
16 Aug 2023 13:27 |
Last Modified: |
16 Feb 2024 00:25 |
Publisher DOI: |
10.1029/2023GB007785 |
BORIS DOI: |
10.48350/185498 |
URI: |
https://boris.unibe.ch/id/eprint/185498 |