ABSTRACT We request funds to purchase a mass spectrometer for stable isotope studies using 13C and lSN. The Europa 20/20 instrument combines a high precision mass spectrometer with a gas chromatograph-thermal conductivity detector and automated sample inlet system that permits analysis of 66 samples for both mass and isotopic composition. The instrument would eliminate the use of 14C, a radioactive isotope, for ongoing time-series measurements of primary production and so free us from the high costs of disposal from a remote oceanic site. In addition, it would permit concurrent analysis of both primary production and nitrogen cycling. The new instrument would replace our current instrument for 15N analysis, an emission spectrometer, to provide increased sensitivity and automated sample preparation. Savings would also accrue from measuring the sample mass (carbon & nitrogen) and isotope composition on a single sample rather than from multiple samples and separate analyses as is currently required. Our existing courses to train foreign scientists in established methods for global change research would be modified to include instruction in stable isotope techniques.
