17O in Bioapatit as paleo-CO2-barometer
Mineralogy, Petrology and Geochemistry
Final Report Abstract
In this project, we studied the triple O isotope composition of a large and comprehensive set of bioapatite samples from marine and land-living vertebrates. For the marine vertebrates we were able to identify a signature of isotopically anomalous atmospheric O2 in the bioapatite. A strong metabolic signature of inhaled air O2 is observed in marine mammal, which is result of their high water efficiency. Although they live in water, they are short on freshwater. The comprehensive dataset for land-living mammals demonstrates the variability within communities and the variation in triple O isotope compostion in different climatic regions. Finally, we observed a signature of lower Δ’17O of air O2 for Jrassic and Triassic land-living vertebrates. This lower Δ’17O is attributed to an elevated CO2 mixing ratio at that time. Our finding is in good agreement to proxy data.
