The session was one of the largest in the conference comprising 34 oral presentations, split into three 3-hour blocks, and 16 poster presentations. Presenters and attendees included a broad cross-section of practitioners in the field, from institutions in Europe, North America and Asia in early to senior career positions, also gathering many of Carl’s former and current collaborators.

“Carl has been instrumental in developing these wonderfully complex computer codes that allow integration of geochemical processes over time and space,” noted Eric Oelkers (KAUST). Pierre Regnier (Université Libre de Bruxelles) reminisced how Carl “guided him to apply complex reactive transport models to estuarine systems,” while Sue Brantley (Penn State) lauded “Carl’s receptiveness to ideas and work with [others] on ideas and [translating] them into models.”

The session showcased the breadth of topics that the reactive transport approach is applied to and the maturity the discipline has reached. As Carl noted in his session-opening keynote address, this serves as an indication that reactive transport is now an essential tool for the analysis of coupled physical, chemical, and biological processes in Earth systems, including Subsurface Energy and Water and the Critical Zone. Christophe Tournassat (Université d’Orléans and Berkeley Lab) pointed out how “[Carl] has paved the way” on many of the topics reactive transport is being used for.

Carl Steefel is an EESA Senior Scientist and serves as the Geochemistry Department Head. He is an AGU Fellow (2018), received the Berkeley Lab Director’s Award for Exceptional Scientific Achievement in 2020, and an R&D 100 Award for the reactive transport software CrunchFlow/CrunchTope in 2017.