Photo of Reid Clark
Professional Scientist II, Stable Isotope Lab • Stable isotope gas chromatography-mass spectrometry

Prounouns: he/him

Stable Isotope Lab


Reid collaborates with a small team of professional scientists to routinely diagnose, troubleshoot, and repair a fleet of dual-inlet and continuous flow isotope-ratio mass spectrometers to produce accurate and precise datasets for over 20,000 air sample measurements annually. The carbon and oxygen isotope measurements of atmospheric carbon dioxide and methane are used in a 30+ year partnership between INSTAAR and the NOAA Global Monitoring Labtratory using NOAA's Global Greenhouse Gas Reference Network to study the sources and sinks in the modern-day carbon cycle. 

The INSTAAR Stable Isotope Lab (SIL) has been measuring isotopes of atmospheric methane since 1998, and is the largest methane isotope dataset in the world. Reid has served as the day-to-day lead of the methane istotope dataset since late-2020.

Prior to his time at INSTAAR, Reid worked in a team of researchers investigating marine sediment paleoclimate archives as analogs to modern-day anthropogenic climate change. He utilized inductively coupled plasma mass spectrometry and scanning electron microscopy of foraminifera to infer past changes in ocean temperature, acidity, and salinity due to large-scale carbon cycle perturbations during the early Eocene.  


  • B.S. (Earth & Planetary Sciences): University of California Santa Cruz


  • Magna cum laude, University of California Santa Cruz
  • Highest Honors, Department of Earth & Planetary Sciences

Selected publications

Michel, S.E., Clark, J.R., Vaughn, B.H., Crotwell, M., Madronich, M.,Moglia, E., Neff, D., Mund, J. (2022), University of Colorado, Institute of Arctic and Alpine Research (INSTAAR). Stable Isotopic Composition of Atmospheric Methane (13C) from the NOAA GML Carbon Cycle Cooperative Global Air Sampling Network, 1998-2021. Version: 2022-12-15