A. Hope Jahren

2005 James B. Macelwane Medal Winner

Johns Hopkins University

A. Hope Jahren received the James B. Macelwane Medal at the AGU Fall Meeting Honors Ceremony, which was held on 7 December 2005 in San Francisco, Calif. The medal is given for significant contributions to the geophysical sciences by a young scientist of outstanding ability.


It is a great honor to introduce A. Hope Jahren as a recipient of this distinguished award. Hope is an exceptional young scientist who has established an international reputation as a leader in the new field of geobiology. By integrating sophisticated biological techniques and concepts into geological inquiry, Hope is making forefront advances that are en route to a reform in how we view the field of paleoclimatology.

Hope has established this place for herself in the Earth sciences because of her unique interdisciplinary background studying soils, plants, geology, and stable isotopes. She is also highly creative and imaginative. These talents, combined with her hardworking nature, have resulted in a path of remarkable productivity.

Hope’s post-undergraduate experience began with a Fulbright award to Norway in 1992 that subsequently led her to focus her Ph.D. research on biomineralization processes in plants. From her resulting dissertation, she published many papers on isotopic studies of plant biominerals, and this experience clearly shaped her thinking. While editing a book on biomineralization in 2003, I realized that Hope is probably the only person who has done stable isotope work on plant biominerals per se.

During her time at Georgia Tech [Atlanta, Ga.], Hope pioneered the use of carbon isotopes in ancient plant fossils to give information about paleoatmospheres. There were skeptics, but she knew her work had uncovered important findings. She went on to diagnose the second known major methane hydrate release event (117 million years ago), thus establishing methane hydrate release as an episodic event in Earth’s history. These papers led to the GSA Donath Medal.

After relocating to Johns Hopkins [Baltimore, Md.], most of her time was spent on the Axel Heiberg locale, a 45-million-year-old fossil forest [in Canada’s Arctic islands] where her group did field work for three summers. Using stable isotopes, she made findings that startled the community by quantifying the temperature, humidity, weather patterns, and dominant methanogenic soil biological pathways of the site’s ancient paleoclimate.

Building on her background and findings, Hope is now moving the geobiology field ahead yet again. She is combining molecular biochemical techniques with stable isotope techniques in ways that will revolutionize paleontology. To do this, she received another Fulbright award to spend a year at the Botanical Institute of the University of Copenhagen [Denmark] learning DNA extraction, purification, amplification, and sequencing-only a few people have received Fulbrights to two countries. Upon returning, she has become the first person to measure stable isotopes on the DNA of multicellular organisms. Even more remarkably, she is also the first person to extract, sequence, and perform stable isotope analysis on DNA from paleosols.

Hope has well earned her reputation as an intellectual leader in geobiology, and new work has her on a path to become a world authority over the next 10 years. Her contributions are all the more remarkable when one considers the disciplinary breadth and communication that this kind of research requires; and the urgency of advancing paleoenvironmental science to a focus on genetic information combined with insights from stable isotopes.

Finally, it is always great to see these awards go to wonderful people such as Hope. She is a delightfully clever person with a fun sense of humor. As you might expect, she is also a compassionate teacher. It gives me great pleasure to present her to you as a very worthy recipient of this year’s James B. Macelwane Medal.

—PATRICIA M. DOVE, Virginia Polytechnic Institute and State University, Blacksburg


I am honored to be a recipient of the 2005 James B. Macelwane Medal, and glad to have this opportunity to thank the many people who provided me with opportunities, encouragement, and motivation these many years. There are many special people who went out of their way to help me grow at various points in my journey. To my teachers and mentors at the University of Minnesota-Larry Edwards, Chris Paola, David Kohl-stedt-I am grateful for the encouragement and attention you gave to me. To the CICERO [Center for International Climate and Environmental Research-Oslo] group at the University of Oslo [Norway], thank you for letting me come home and use my language. To my advisors and mentors at the University of California, Berkeley: Terry Chapin, Pam Matson, Ron Amundson, Raymond Jeanloz, Jim Kirchner, all of whom helped me in different ways.

To my young colleagues at Georgia Tech-Joe Montoya, Trish Dove, Dana Hartley, Phillippe Van Capellen, Lars Stixrude, Kavita Philips-I am glad you were there while I was there. To my colleagues at the University of Copenhagen: Ole Seberg, Gitte Petersen, John Mundy, and Eske Willerslev, who patiently taught me the art of molecular biology and phylogeny.

To the faculty of the Johns Hopkins University, especially Steve Stanley, David Veblen, Dimitri Sverjensky, Peter Olson, and Lynn Roberts-I value your support and encouragement every day. To my brilliant coauthors Nan Crystal Arens [Hobart and William Smith Colleges, Geneva, N.Y.] and Leo Sternberg [University of Miami, Coral Gables, Fla.]. I am fortunate to share and shape your ideas, as you do mine.

Along this road, I have received mentoring from so many: Isabel Montañez, Crayton Yapp, Sam Savin, Yang Wang, Libby Stern, Carolina Lithgow-Bertelloni, Greg Retallack, Cinzia Cervato, Lynn Walter, Andy Elby, Tim Bralower, Phil Meyers, Cathy Skinner, Bill Schlesinger, Steve Macko, and so many more. I have had the great fortune to work with talented and dedicated students: Maggie Neff, Amy Abdallah, Steve Porter, Scott Werts, Stephanie Harbeson, Lev Horodyskyj, Jon Wilson, Lori Cabena, Moses Rifkin, Kristen Sanford, and more my pride in you grows every year. I have worked side by side for more than 10 years now with the best scientist I know: my technician Bill Hagopian [Johns Hopkins University]. I would not, and could not, do this work without him.

I hold dear the regard my friends and family have given me along the way. I love my two guys, aged 18 months and 408 months, who comprise one focus of my newly elliptical life. Thank you again. Thank you sincerely.

—A. HOPE JAHREN, Johns Hopkins University, Baltimore, Md.