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Magnitude and origin of the anthropogenic CO 2 increase and 13 C Suess effect in the Nordic seas since 1981
Author(s) -
Olsen Are,
Omar Abdirahman M.,
Bellerby Richard G. J.,
Johannessen Truls,
Ninnemann Ulysses,
Brown Kelly R.,
Olsson K. Anders,
Olafsson Jon,
dal Gisle,
Kivimäe Caroline,
Kringstad Solveig,
Neill Craig,
Olafsdottir Solveig
Publication year - 2006
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 - 10.1029/2005gb002669
Subject(s) - water mass , oceanography , north atlantic deep water , environmental science , advection , dissolved organic carbon , thermohaline circulation , geology , physics , thermodynamics
This study evaluates the anthropogenic changes of CO 2 (ΔC ant ) and δ 13 C (Δ δ 13 C ant ) in the Nordic seas, the northern limb of the Atlantic Meridional Overturning Circulation, that took place between 1981 and 2002/2003. The changes have been determined by comparing data obtained during the Transient Tracers in the Ocean, North Atlantic Study (TTO‐NAS) with data obtained during the Nordic seas surveys of R/V Knorr in 2002 and R/V G.O. Sars in 2003 using an extended multilinear regression approach. The estimated Δ δ 13 C ant and ΔC ant and their relationship to each other and to water mass distribution suggest that the Polar Water entering the Nordic seas from the north is undersaturated with respect to the present atmospheric anthropogenic CO 2 levels and promotes a local uptake of C ant within the Nordic seas. In contrast, the Atlantic Water entering from the south appears equilibrated. It carries with it anthropogenic carbon which will be sequestered at depth as the water overturns. This preequilibration leaves no room for further uptake of C ant in the parts of the Nordic seas dominated by Atlantic Water. The upper ocean p CO 2 in these regions appears to have increased at a greater rate than the atmospheric p CO 2 over the last 2 decades; this is reconcilable with a large lateral advective supply of C ant .