Marisa Repasch, an assistant professor in the Department of Earth and Planetary Sciences at The University of New Mexico (UNM), has received the 2025 Early Career TUNDRA Award. The award, known as Toolik Userdays for Naturally Developing Research Abilities, supports early career scientists with research resources at Toolik Field Station in Alaska.
The TUNDRA Award offers logistical support, accommodations, meals, and field equipment to help researchers conduct pilot studies in Arctic environments. This year, Repasch used the opportunity to carry out fieldwork in the Atigun River watershed alongside collaborators Preston Kemeny from Woods Hole Oceanographic Institution and Marc Dumont from Colorado School of Mines.
Repasch’s research focuses on how erosion, sediment transport, and chemical weathering interact with the global carbon cycle—particularly in Arctic regions affected by permafrost thaw. “This award allowed us to go to the field together for the first time and collect a sample set for a pilot study, which will be used to develop future proposals—and the results may be publishable on their own,” Repasch said. “I also don’t currently have research funding to return to the Arctic for a large project, so the TUNDRA award enabled me to get back to the field with limited resources.”
During their June expedition at Toolik Field Station, Repasch and her team collected river and stream water samples, suspended sediment, bedrock cores, and electrical resistivity data. “The samples and data we collected will be linked to understand how the depth of permafrost thaw influences the depth of chemical weathering—and therefore the oxidation of rock organic carbon and sulfide minerals like pyrite,” Repasch explained. “These processes have important implications for atmospheric CO₂ and water quality.”
This trip marked Repasch’s first direct collaboration with Kemeny. Their complementary expertise led them to submit a proposal to the National Science Foundation aimed at expanding their pilot study into a multi-season investigation of Arctic carbon cycling. “My collaborator Preston has been studying water chemistry in permafrost-affected watersheds since his Ph.D. at Caltech,” Repasch said. “It was a great experience to work together in the field, think about the landscape, and discuss new ideas for this research.”
Samples from their campaign are now being analyzed at UNM’s Center for Stable Isotopes and Analytical Geochemistry Labs. According to Repasch: “It is amazing to be at a university where these state-of-the-art analytical facilities are accessible to both faculty and students. We are fortunate to have these labs staffed by dedicated research scientists who maintain the instruments and ensure high-quality data.”
The project also offers training opportunities for UNM students; Repasch plans involvement for both graduate and undergraduate students during sample analysis phases.
“The findings from this work will help us better model how landscape change in Arctic mountain regions influences the carbon cycle and atmospheric CO₂,” she said. “That has broad implications not just for climate science, but for understanding how Earth’s surface responds to rapid environmental change.”
