Skip to main content

When can ocean acidification impacts be detected from decadal alkalinity measurements?

Author(s): Carter, Brendan R; Frölicher, Thomas L; Dunne, John P; Rodgers, Keith B; Slater, Richard D; et al

To refer to this page use:
Abstract: We use a large initial condition suite of simulations (30 runs) with an Earth system model to assess the detectability of biogeochemical impacts of ocean acidification (OA) on the marine alkalinity distribution from decadally repeated hydrographic measurements such as those produced by the Global Ship‐Based Hydrographic Investigations Program (GO‐SHIP). Detection of these impacts is complicated by alkalinity changes from variability and long‐term trends in freshwater and organic matter cycling and ocean circulation. In our ensemble simulation, variability in freshwater cycling generates large changes in alkalinity that obscure the changes of interest and prevent the attribution of observed alkalinity redistribution to OA. These complications from freshwater cycling can be mostly avoided through salinity normalization of alkalinity. With the salinity‐normalized alkalinity, modeled OA impacts are broadly detectable in the surface of the subtropical gyres by 2030. Discrepancies between this finding and the finding of an earlier analysis suggest that these estimates are strongly sensitive to the patterns of calcium carbonate export simulated by the model. OA impacts are detectable later in the subpolar and equatorial regions due to slower responses of alkalinity to OA in these regions and greater seasonal equatorial alkalinity variability. OA impacts are detectable later at depth despite lower variability due to smaller rates of change and consistent measurement uncertainty.
Publication Date: 18-Apr-2016
Citation: Carter, Brendan R., Thomas L. Frölicher, John P. Dunne, Keith B. Rodgers, Richard D. Slater, and Jorge L. Sarmiento. "When can ocean acidification impacts be detected from decadal alkalinity measurements?" Global Biogeochemical Cycles 30, no. 4 (2016): 595-612. doi:10.1002/2015GB005308.
DOI: doi:10.1002/2015GB005308
ISSN: 0886-6236
EISSN: 1944-9224
Pages: 595 - 612
Type of Material: Journal Article
Journal/Proceeding Title: Global Biogeochemical Cycles
Version: Final published version. This is an open access article.

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.