Ellen R. M. Druffel

University of California Irvine

2016 Roger Revelle Medal Winner

Ellen R. M. Druffel was awarded the 2016 Roger Revelle Medal at the AGU Fall Meeting Honors Ceremony, held on 14 December 2016 in San Francisco, Calif. The medal is for “outstanding contributions in atmospheric sciences, ­­atmosphere-­ocean coupling, ­­atmosphere-­land coupling, biogeochemical cycles, climate or related aspects of the Earth system.”


Ellen Druffel is an explorer and scientific pioneer. Over her career, she has developed the measurement of radiocarbon (  14C) as a tool for studying timescales of ocean carbon cycling. Her research has paralleled a technological revolution allowing a shift from detecting the occasional flash of radioactive decay in bulk samples to counting individual 14C atoms in single compounds extracted from water or sediments. In both cases, her laboratory’s meticulous attention to detail and development of new methods mean that Ellen’s results are not only trusted for their accuracy but often the first observations of their kind.

Ellen’s early work with Pete Williams at Scripps Institution of Oceanography required painstaking field and laboratory work to document profiles of radiocarbon in the open ocean, including both dissolved and particulate organic matter. Surprisingly, the mean radiocarbon age of dissolved organic carbon was thousands of years, even though its ultimate source is newly photosynthesized carbon. In attempting to explain this mystery, Ellen and her group have fundamentally altered our understanding of ocean organic matter through the recognition that dissolved and particulate matter consist of many distinct, differently aged components. Recent work investigates the roles of black carbon and recycling of sedimentary carbon in explaining old organic carbon.

Another of Ellen’s major contributions is the use of 14C in corals as recorders of past change in ocean ventilation and mixing. The amassed data from her global coral archive provide unique, continuous records of tropical ocean circulation and reveal temporal variations in phenomena such as the El Niño–Southern Oscillation over the past millennium. They also record patterns of uptake of ­­­bomb-­­­produced radiocarbon in the surface oceans that constrain estimates of ­­­ocean-­­­atmosphere exchange CO2 used in global climate models.

Ellen has made major contributions to AGU and its community through her leadership and deportment. Her sense of adventure has led her to explore the oceans, from scuba diving to ocean vessels and deep submersibles, and inspires a new generation of students. Her commitment to the advancement of oceanographic research and to forwarding women’s careers in science has impact far beyond her scientific discoveries.

As a longtime colleague in the Earth System Science Department at the University of California, Irvine, we salute Ellen as a kind and conscientious coworker with a wicked sense of humor. We think she is an adventurous, courageous researcher, like Roger Revelle, and are thrilled that she is this year’s Revelle Medal winner.

—Susan Trumbore, Max Planck Institute of Biogeochemistry, Jena, Germany; and Michael Prather, University of California, Irvine


I am humbled by this honor and am very grateful to AGU and to Michael Prather and Sue Trumbore for their generous citation. It is important to emphasize that our research has relied heavily on collaborations with many colleagues over the past years. I share this honor with them.

Most important is my colleague, Sheila Griffin. Sheila and I have worked together for 38 years, since our time at University of California, San Diego. Sheila has trained our students in laboratory and vacuum line techniques, made ­­­high-­­­precision isotopic measurements, planned and participated in many cruises, designed equipment, run our lab, and is a dear friend. Without Sheila’s contributions, I would not be here tonight.

To my husband, Steve, who has always supported and believed in me, I thank you. You are a terrific husband and a wonderful father to our children, Kevin and Rachel. You fill our lives with inspiration, laughter, and love and put up with my occasional ­­­absentmindedness.

To our students and postdocs, it is your contributions, your blood, sweat, and tears, that have made our research program move forward. And your good-natured banter, which includes rubber chickens and rats, has been particularly heartwarming.

In the early 1990s, I was welcomed into the new Earth System Science group at University of California, Irvine, pioneered by Ralph Cicerone. They provided a fertile, supportive atmosphere for us to learn, to dream, to build, and to grow. I am so grateful to Peter M. Williams, my mentor who taught me how to ask important questions, and to work like the dickens to make difficult measurements. I remember his words, “If this was easy, someone would have done it a long time ago.” I still miss you, Pete. My colleagues Cindy Lee, Lihini Aluwihare, Ann McNichol, Robbie Toggweiler, Rob Dunbar, Brett Walker, Sue Trumbore, John Southon, and Bill Cain have provided inspiration and friendship along the way. Thanks to my parents, who encouraged me to achieve my dream of becoming a scientist.

In 1957, Roger Revelle and Hans Suess published a paper in Tellus wherein they made initial estimates of the buildup of excess CO2 in the atmosphere and ocean by the early 21st century. My group has worked on a small part of this big problem. We are truly fortunate to be able to ask scientific questions and spend time, sometimes lots of time, trying to answer them. Thank you, again, for this honor.

—Ellen R. M. Druffel, University of California, Irvine