Marshall L. Otter
Office Tel: 508-289-7462
Lab Tel: 508-289-7762
Ph.D., Geochemistry, University of Cape Town, South Africa, 1990
B.A., Geology, Humboldt State University, Arcata, California, 1980
I was introduced to stable isotopes in the mid-1980’s while studying the geochemistry of diamonds at the University of Cape Town. We combusted diamond fragments using a glass vacuum line and analyzed the resulting CO2 gas for δ13C on a dual-inlet VG 602 mass spectrometer. In the early 1990’s, I was involved with early efforts at in-situ δ13C microanalysis of diamonds using SIMS technology at the University of Edinburgh. In the mid-1990’s, I managed the stable isotope division at Geochron Laboratories, a commercial lab in Massachusetts, where we analyzed virtually any material for δ13C, δ15N, δ18O, δ2H and δ34S. In the late 1990’s, I did a brief stint at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston analyzing doubly-labeled water (i.e., urine) for δ18O and δ2H, and also CO2 in breath for δ13C, using a Europa 20-20 continuous-flow system.
In 2000, I accepted my current position here at the MBL Stable Isotope Laboratory where, until recently, we have concentrated on analyzing bulk organics for δ5N and δ13C using automated Finnigan Delta S and Europa 20-20 systems. In 2006, we purchased two new GV Instruments Isoprime mass spectrometers and a variety of automated sample preparation/purification units that allow us to analyze a greater variety of ecological sample materials for δ13C, δ15N,δ34S, δ18O and δ2H. I now split my time between production work (i.e., running routine analyses) and method development on our new instruments.