Effect of light intensity on skeletal d13C and d18O in the Porites corals: Light controlled culture experiment

Abstract

Previously we reported (Omata et al., 2005, GCA, v 69, p3007-3016) that annual fluctuation in skeletal carbon stable isotope is result of the mixture of two isotopic disequilibrium processes as kinetic and metabolic isotope effects. To examine these effects, we conducted in vitro culture experiments to examine effects of light intensities on carbon and oxygen isotope variations in Porites spp.
At the result of analysis, compositional changes in carbon and oxygen isotope ratios showed simultaneous transitions, caused by the kinetic fraction due to lack of metabolic fraction. It may represent that metabolic isotope effects increased with increasing light intensity, and the kinetic isotope effects with increasing the growth rate.