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Revelle revisited: Buffer factors that quantify the response of ocean chemistry to changes in DIC and alkalinity
Author(s) -
Egleston Eric S.,
Sabine Christopher L.,
Morel François M. M.
Publication year - 2010
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2008gb003407
Subject(s) - alkalinity , ocean acidification , seawater , dissolved organic carbon , chemistry , ocean gyre , dissolution , carbon dioxide , buffer (optical fiber) , environmental chemistry , environmental science , oceanography , ecology , geology , subtropics , biology , telecommunications , organic chemistry , computer science
We derive explicit expressions of the Revelle factor and several other buffer factors of interest to climate change scientists and those studying ocean acidification. These buffer factors quantify the sensitivity of CO 2 and H + concentrations ([CO 2 ] and [H + ]) and CaCO 3 saturation (Ω) to changes in dissolved inorganic carbon concentration (DIC) and alkalinity (Alk). The explicit expressions of these buffer factors provide a convenient means to compare the degree of buffering of [CO 2 ], [H + ], and Ω in different regions of the oceans and at different times in the future and to gain insight into the buffering mechanisms. All six buffer factors have roughly similar values, and all reach an absolute minimum when DIC = Alk (pH ∼ 7.5). Surface maps of the buffer factors generally show stronger buffering capacity in the subtropical gyres relative to the polar regions. As the dissolution of anthropogenic CO 2 increases the DIC of surface seawater over the next century, all the buffer factors will decrease, resulting in a much greater sensitivity to local variations in DIC and Alk. For example, diurnal and seasonal variations in pH and Ω caused by photosynthesis and respiration will be greatly amplified. Buffer factors provide convenient means to quantify the effect that changes in DIC and Alk have on seawater chemistry. They should also help illuminate the role that various physical and biological processes have in determining the oceanic response to an increase in atmospheric CO 2 .