Alan M. Seltzer, University College Dublin, Ireland
2026 Houtermans Award medallist
Alan Seltzer is an Assistant Professor in the School of Earth Sciences at University College Dublin and an affiliated scientist at Woods Hole Oceanographic Institution (WHOI), where he leads an isotope tracer laboratory. His research uses naturally occurring gas isotopes to quantify physical and biogeochemical processes across the Earth system, with applications spanning groundwater hydrogeology, terrestrial paleoclimate, air-sea gas exchange, mantle volatile transport, and nitrogen cycling in aquatic environments.
Alan was first introduced to geochemistry as a high school intern in the soil biogeochemistry laboratory of Jason Neff at the University of Colorado Boulder. He completed a B.A. in Earth Science and Computer Science at Columbia University in 2014, conducting research across multiple laboratories at Lamont-Doherty Earth Observatory. Working with Martin Stute and Joerg Schaefer, he developed a lasting interest in noble gases as physical tracers through a project reconstructing groundwater recharge temperatures in New Zealand since the last ice age.
He pursued his Ph.D. at the Scripps Institution of Oceanography from 2014 to 2019 under the mentorship of Jeff Severinghaus. During his doctoral research, Alan developed a dynamic dual-inlet isotope-ratio mass spectrometry technique to measure dissolved Ar, Kr, and Xe isotopes in groundwater at sub-per-mil precision to resolve gravitational fractionation at the ~0.005‰/amu level as a proxy for paleo-water-table depth. He applied this approach to reconstruct declining groundwater levels in the southwestern United States during the last deglaciation. In parallel, in collaboration with Roberta Hamme and Frank Pavia, he adapted the technique to investigate noble-gas disequilibrium in the deep ocean as a quantitative tracer of air-sea gas exchange.
From 2019 to 2021, Alan was a postdoctoral scholar at WHOI under the mentorship of Peter Barry and Roo Nicholson. Working with Barry, Michael Broadley, David Bekaert, and Bernard Marty, he extended the dynamic noble gas isotope technique to high-precision measurements of Ar, Kr, and Xe isotopes in volcanic gas emissions, enabling new constraints on volcanic gas histories and transport in the coupled solid Earth-atmosphere system. In 2021, Alan joined the scientific staff in WHOI’s Marine Chemistry and Geochemistry Department and established a laboratory focused on noble gas, nitrogen, and oxygen isotopes in groundwater, seawater, air, and volcanic gases. Through collaboration with Bill Jenkins, he expanded oceanic applications of noble-gas tracers for air-sea exchange and glacial meltwater input. More recently, together with his student Katelyn McPaul and colleague Scott Wankel, he has adapted these approaches for high-precision N2 isotope measurements in groundwater, advancing tools to quantify nitrogen cycling in aquatic systems.
Since 2025, Alan has been a faculty member at University College Dublin, where he serves as Assistant Professor of Hydrogeology and Ad Astra Fellow, leading a research programme focused on tracer-based approaches to understanding groundwater systems.
Additional information and a list of publications can be found here.