(1958- ) American Aqueous Geochemist
Environmental geology commands the most interest and concern of all of the fields in Earth science today. A large part of this field is the chemical system formed by the interaction of rocks, fluids, and gases. It not only affects issues like water quality and pollution control, but air quality and the greenhouse effect. These complex interactions are the mainstay of the field of aqueous geochemistry, of which Susan Brantley is one of the premier experts. She studies the chemical processes and compositional control of natural waters both at the surface of the Earth as well as deeper in the crust. This research is conducted both with laboratory experimentation as well as in field areas from the deserts of Peru to the glaciers of Iceland. Experimental work involves dissolution studies of certain minerals under a variety of conditions to simulate weathering as well as subsurface process. Brantley has produced two important volumes on this work, including Geochemical Kinetics of Mineral-Water Reactions in the Field and in the Lab and Chemical Weathering Rates of Silicate Minerals. She is especially interested in feldspars, including the effect of coatings, and the release of trace components. However, she has also conducted dissolution studies on many other minerals including olivine, antho-phyllite, and pyroxene among others. Another interesting aspect of this research is the study of the effect of bacteria on weathering. Bacteria and other microbes are situated right at the interface between the fluid and the mineral surfaces where all weathering and other fluid-rock interactions take place. She has documented the removal of iron from the silicate mineral surfaces by long-lived bacteria colonies. This field of biogeochem-istry is one of the most promising directions in geology. It not only has implications for environmental sciences but for material sciences and possibly even for the medical field. Bacteria can enhance dissolution or stabilize surfaces as well as provide a buffering control on the composition of fluids.
In addition to this experimental and detailed mineral research, Brantley and her students have conducted some interesting field projects. The field projects are typically designed to complement the experimental research. She does research on the hydrogeochemistry of active volcanoes. Several of these volcanoes have included Volcan Poas in Costa Rica, Grimsvotn in Iceland, and Ol’Doinyo Lengai in Tanzania. The Costa Rica research was completed on the chemistry of La-guna Caliente, one of the most acidic natural waters in the world with pH consistently below zero. Brantley is also studying the carbon dioxide flux from the geysers and other geothermal features of Yellowstone National Park, Wyoming. A similar study documents the degassing of the volcanic field in Campi Flegrei in Italy.
Susan Brantley was born on August 11, 1958, in Winter Park, Florida. She attended Princeton University, New Jersey, where she earned a bachelor of arts degree in chemistry (magna cum laude) in 1980. In 1980-81, Brant-ley was a Fulbright Scholar in Peru. She also completed her graduate studies at Princeton University, where she earned a master of arts and a Ph.D. degree in geological and geophysical sciences in 1983 and 1987, respectively. Brantley was a National Science Foundation Graduate Student Fellow and an IBM Student Fellow for much of her graduate career. In 1986, she joined the faculty at Pennsylvania State University at University Park, where she remains as of 2002. She became the director of the Center for Environmental Chemistry and Geochemistry in 1998 and the director for the Biogeochemical Research Initiative for Education in 1999. In 1995, Brantley was a visiting scientist at both the U.S. Geological Survey in Menlo Park, California, and Stanford University, California.
Susan Brantley is still in the early stages of a productive career. She is an author of some 78 scientific publications in international journals, professional volumes, and conference proceedings. Many of these papers are seminal studies on ge-omicrobiology and processes of aqueous geochemistry and appear in the best of journals including the high-profile journal Nature. She is also an editor of two professional volumes. Brantley has received several honors and awards in recognition of her research contributions to the geologic profession. She received the Presidential Young Investigator Award through the National Science Foundation (1987-1992), the David and Lucile Packard Fellowship (1988-1993), and the Wilson Research Award from Pennsylvania State University (1996).
Brantley has performed outstanding service to the profession at this point in her career. She served as councilor for the Geochemical Society as well as a member of several committees. She also served on committees and panels for the Na tional Research Council, the National Academy of Sciences, and the National Science Foundation. She served in several editorial capacities including editor for both Chemical Geology and Geofluids as well as assistant editor for Chemical Geology.
