Isotopenfraktionierung im Sauerstoffzyklus der Erde / Isotope Fractionation occuring in the Oxygen Cycle

Abstract

The present data on isotope fractionation factors involved in the oxygen cycle are reviewed. Physical models for the isotope fractionation of respiratory processes and photosynthesis on land as well are discussed. The consistency of all data is examined on the basis of a 2 box model (atmosphere and an ocean surface layer containing 90% of marine biomass). From this balance, the O₂ exchange rate between the two reservoirs results as 1/3 of the marine production. This seems to be too low and therefore indicate that either one figure is bad or the isotope exchange between CO₂ and O₂ is more important than expected.