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Rapid decline of the CO 2 buffering capacity in the North Sea and implications for the North Atlantic Ocean
Author(s) -
Thomas Helmuth,
Friederike Prowe A. E.,
van Heuven Steven,
Bozec Yann,
de Baar Hein J. W.,
Schiettecatte LaureSophie,
Suykens Kim,
Koné Mathieu,
Borges Alberto V.,
Lima Ivan D.,
Doney Scott C.
Publication year - 2007
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 - 10.1029/2006gb002825
Subject(s) - oceanography , middle latitudes , water column , north atlantic oscillation , environmental science , carbonate , surface water , seawater , dissolved organic carbon , north atlantic deep water , sea surface temperature , climatology , geology , thermohaline circulation , chemistry , organic chemistry , environmental engineering
New observations from the North Sea, a NW European shelf sea, show that between 2001 and 2005 the CO 2 partial pressure ( p CO 2 ) in surface waters rose by 22 μ atm, thus faster than atmospheric p CO 2 , which in the same period rose approximately 11 μ atm. The surprisingly rapid decline in air‐sea partial pressure difference (Δ p CO 2 ) is primarily a response to an elevated water column inventory of dissolved inorganic carbon (DIC), which, in turn, reflects mostly anthropogenic CO 2 input rather than natural interannual variability. The resulting decline in the buffering capacity of the inorganic carbonate system (increasing Revelle factor) sets up a theoretically predicted feedback loop whereby the invasion of anthropogenic CO 2 reduces the ocean's ability to uptake additional CO 2 . Model simulations for the North Atlantic Ocean and thermodynamic principles reveal that this feedback should be stronger, at present, in colder midlatitude and subpolar waters because of the lower present‐day buffer capacity and elevated DIC levels driven either by northward advected surface water and/or excess local air‐sea CO 2 uptake. This buffer capacity feedback mechanism helps to explain at least part of the observed trend of decreasing air‐sea Δ p CO 2 over time as reported in several other recent North Atlantic studies.