Lead
Characterization of atmospheric oxygen based on high precision, multi-collector isotope ratio mass spectrometry.

Lay summary
This project allows us to purchase a dedicated mass spectrometer with a wide geometry for simultaneous recording of mass to charge ratios from 32 to 36 with highest precision. The fact that the masses from 32 through to 36 are measured simultaneously allows us to perform high precision measurements of all isotopologues of atmospheric molecular oxygen, including Δ17O (a 17Oexcess value determined from a 17O/16O to a scaled 18O/16O value) as well as Δ35 and Δ36. This instrument gives us the opportunity to to determine the isotopic composition of atmospheric oxygen among others. This composition carries a mixed signal originating from fractionations associated with the terrestrial biosphere exchange, stratospheric O2 and CO2 isotope exchange and evapotranspiration. We expect further constraints on the strongly variable terrestrial biosphere uptake from these measurements.