Comparison of the August - September 1991 and 1979 Surface
Partial Pressure of CO2 Distribution in the Equatorial Pacific Ocean Near 150°W.

C. Goyet and E. T. Peltzer
Marine Chemistry and Geochemistry Department
Woods Hole Oceanographic Institutiton
Woods Hole, MA 02543

Marine Chemistry (1994) 45: 257-266.

Received: 16 April 1993.
Accepted: 4 October 1993.


The partial pressure of CO2 (pCO2) in the surface seawater and marine air from 17°S to 22°N near 151°W (WOCE leg P-16c) during the period from August 31 to September 29, 1991, were measured continually. The surface seawater pCO2 showed large latitudinal variation with a maximum of 425 µatm near the equator. These results are compared with pCO2 measurements in 1979, in the same area and same months. The short-scale (temporal and spatial) variations in surface seawater pCO2 (±6.1 µatm) do not allow us to unequivocally quantify the variation in delta-pCO2 (pCO2sea - pCO2air) between the years 1979 and 1991 due to oceanic uptake of fossil fuel CO2. However, the data suggest that this ocean area might be a stronger source of CO2 for the atmosphere than may be expected from results of ocean models.


We thank the captain and the crew of the R/V Thomas Washington for their cooperation during the sampling cruise; the National Science Foundation and in particular N. Andersen for their support; F. J. Millero and P. G. Brewer for their helpful comments on an earlier version of the manuscript; R. Weiss for his 1979 data set and for many stimulating discussions; and C. S. Wong and R. Feely for their constructive reviews. This work was supported by the Department of Energy under grant DE-FG-02ER60980 and National Aeronautics and Space Administration grant NAGW-2431.

This is contribution number 8198 from the Woods Hole Oceanographic Institution.

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