Reports

Carbon Dioxide Transport by Ocean Currents at 25°N Latitude in the Atlantic Ocean

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Science  27 Oct 1989:
Vol. 246, Issue 4929, pp. 477-479
DOI: 10.1126/science.246.4929.477

Abstract

Measured concentrations of CO2, O2, and related chemical species in a section across the Florida Straits and in the open Atlantic Ocean at approximately 25°N, have been combined with estimates of oceanic mass transport to estimate both the gross transport of CO2 by the ocean at this latitude and the net CO2 flux from exchange with the atmosphere. The northward flux was 63.9 x 106 moles per second(mol/s); the southward flux was 64.6 x 106 mol/s. These values yield a net CO2 flux of 0.7 x 106 mol/s (0.26 ± 0.03 gigaton of C per year) southward. The North Atlantic Ocean has been considered to be a strong sink for atmospheric CO2, yet these results show that the net flux in 1988 across 25°N was small. For O2 the equivalent signal is 4.89 x 106 mol/s northward and 6.97 x 106 mol/s southward, and the net transport is 2.08 x 106 mol/s or three times the net CO2 flux. These data suggest that the North Atlantic Ocean is today a relatively small sink for atmospheric CO2, in spite of its large heat loss, but a larger sink for O2 because of the additive effects of chemical and thermal pumping on the CO2 cycle but their near equal and opposite effects on the CO2 cycle.