Oxygen isotope fractionation in the ocean surface and 18O/16O of atmospheric O2
Article first published online: 2 NOV 2011
Copyright 2011 by the American Geophysical Union.
Global Biogeochemical Cycles
Volume 25, Issue 4, December 2011
How to Cite
2011), Oxygen isotope fractionation in the ocean surface and 18O/16O of atmospheric O2, Global Biogeochem. Cycles, 25, GB4006, doi:10.1029/2011GB004178., and (
- Issue published online: 2 NOV 2011
- Article first published online: 2 NOV 2011
- Manuscript Accepted: 23 SEP 2011
- Manuscript Received: 4 AUG 2011
- δ17O and δ18O of marine dissolved O2;
- Dole effect;
- oxygen isotope fractionation
 We have recently published a new evaluation of Earth's Dole effect, which was based, in part, on measurements of δO2/Ar, δ17O and δ18O of dissolved argon and oxygen in the ocean surface. In calculations of the oxygen isotope effect due to photosynthesis and respiration (ɛup), gross O2 production (G) was an important factor. However, our estimates of G were based on an approximate equation, and in a recent publication it has been suggested that G obtained with this equation could be underestimated by about 33%. If true, such underestimation of G might lead to different ɛup values. To test this possibility, we have used a new rigorous equation with relevant information on isotopic composition of photosynthetic O2 and recalculated ɛup. Given the uncertainties, the new values do not differ from the previous ones, and therefore, the implications of the strong fractionation in the upper ocean (∼25‰) to the global Dole effect remain as in our original publication.