The goal of this project is to upgrade the department's Isotope Ratio Mass Spectrometer (IRMS) because this instrument has become a central instructional tool in several advanced courses and is now essential for the independent study/research participation programs mentored by three faculty members. The instrument allows students to study ecological, physiological and biochemical phenomena with a modern approach utilizing natural abundances of the stable isotopes of carbon (13C) and nitrogen (15N) as quantitative tracers. The upgrade automates sample analyses and facilitates throughput by students, adds a third detector to facilitate isotopic corrections, allows nitrogen analyses to be undertaken readily, and utilizes a computer-controlled analytical system which transmits data to a departmental network for reduction, statistical analyses, and presentation. The instrument is being supported by an IRMS technician who facilitates student training and use. The upgrade is significant because it extends the instrument into the hands of more students in advanced courses and enhances student-mentor opportunities. The grantee institution is matching the NSF award with an equal sum obtained from non-Federal sources.