Dawn Sumner — a UC Davis geologist, planetary scientist and astrobiologist — is among the 53 scientists newly elected as fellows of the American Geophysical Union, or AGU, for outstanding achievements and contributions to earth and space science.
“I deeply appreciate this international recognition for my work,” said Sumner, a professor in the Department of Earth and Planetary Sciences at the College of Letters and Science. “I feel particularly grateful for my colleagues who think so highly of my work that they were willing to spend the hours of work to build my nomination package. This is one of the best measures of the impact my scientific and mentoring contributions have made to geological sciences — the support of my colleagues.”
AGU announced its 2026 class of fellows on Wednesday, Sept. 23.
Sumner’s research combines insights from modern cyanobacterial communities in ice-covered Antarctic lakes with studies of early Earth and Mars to understand the coevolution of life and planets. She is particularly interested in the effects of oxygenic photosynthesis on microbial evolution, ecological changes, and Earth's surface chemistry.
A lifelong lover of the outdoors and geology, Sumner was first drawn to questions about ancient Earth during her undergraduate days at the California Institute of Technology. At CalTech, she analyzed magnetic signatures in rocks to better understand the history of the oxidation of iron on Earth, which provides clues about the planet’s oxygenation history. She further honed her research interests while pursuing a doctoral degree in geology at the Massachusetts Institute of Technology.
Sumner said the AGU’s recognition is particularly poignant because she gave her first professional talk as a researcher at the 1987 AGU Annual Meeting, when she was a senior in college. That talk used magnetic signatures to demonstrate ancient low latitude glaciation, which later became known as the Neoproterozoic Snowball Earth interval, a time roughly 700 million years ago when the planet was covered in ice.
“That abstract has received almost 50 citations on Google Scholar,” said Sumner, who is also a fellow of the American Association for the Advancement of Science, the California Academy of Sciences and The Geological Society of America. “Thus, AGU has been with me my entire professional career.”
Sumner’s AGU recognition highlights the importance of approaching geosciences as an integrative endeavor that values diversity in all its form.
“Species go extinct if they lack diversity. Earth's surface chemistry is the cumulative effect of every localized reaction on a mineral surface and in a cell. Fields of study that lack diversity in approaches and techniques get stuck in dead end ideas. To me, the interdependencies of Earth and life are exquisitely beautiful, and it is a shame when their diversity is flattened into one or two aspects." — Dawn Sumner
“My research, both past and future,” she added, “balances focusing on processes with significant effects with never forgetting that the things I have ignored may end up being just as important.”
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