Associate Professor School of Biology,Georgia Institute of Technology, Atlanta, GA
Ph.D., 1990 Harvard University, Organismic and Evolutionary Biology; A.B., 1980 University of California,Biology
My research interests fall into the general area of biological oceanography, with an emphasis on the planktonic nitrogen cycle of tropical and subtropical oceans. The availability of nitrogen limits biologicalproduction in many parts of the world ocean, and biological processes play a critical role in supplying this critical plant nutrient to the productive upper water column. My research is very interdisciplinary, drawing on both biological and chemical oceanography, as well as the broader field of biogeochemistry. My lab utilizes the stable isotopes of nitrogen as a natural tracer for biologically mediated transformations of nitrogen, an approach that we complement with focused tracer experiments designed to quantify individual fluxes of N through biologically active pools. My research is both field- and laboratory-based, with one or two major cruises per year. Recent field expeditions have included studies of N2-fixation in the SW Pacific and the Sargasso Sea as well as studies of the biogeochemistry of benthic communities associated with methane hydrates in the Gulf of Mexico.
I grew up in the Army and spent a good part of my childhood in Japan and Okinawa, along with time spent Stateside in places like Arizona, Texas and New York. I got to see and live in a variety of environments ranging from small islands to big deserts, and I developed a real appreciation for oceanic places by the time I entered the University of California at Berkeley. I doubt that I could have chosen a better place for college, but I did so haphazardly based on its reputation and its nearness to the Monterey area, where my family settled after my father retired from the Army. At Berkeley, I studied biology and worked in the lab of Ralph Smith, an invertebrate physiologist who sponsored me as an undergraduate researcher and encouraged me to go on to graduate school. I had a great time at Berkeley and have yet to find a place with as much intellectual energy and excitement.
I moved east to Cambridge, Massachusetts for graduate school, where I worked in Jim McCarthy’s lab at Harvard. I’d always been interested in the ocean, but graduate school was my first real opportunity to work at sea, and I put in a fair of sea time along the way to my degree. My dissertation research focused on using the isotopic composition of nitrogen as a way to trace the sources and sinks of nitrogen in estuarine systems such as Chesapeake Bay and offshore waters in the North Atlantic. As a graduate student, I found that I enjoyed teaching very much and I was a resident tutor in one of the Harvard undergraduate Houses in addition to working as a TA in courses ranging from introductory biology to a survey of atmospheric science.
After completing my dissertation, I remained at Harvard as a member of the faculty until 1998, when I moved south to Georgia Tech. My interests have remained strongly interdisciplinary with a heavy emphasis on nutrient cycling in offshore systems. Members of my lab group are currently working on projects including: a study of the interaction between inorganic nitrogen supply and N2-fixation in Trichodesmium, field experiments to quantify the rate of N2-fixation by unicellular cyanobacteria in the North Pacific subtropical gyre, a multidisciplinary study of the biogeochemistry of cold seeps and methane hydrate systems in the Gulf of Mexico, and a field project to quantify the spread of sewage nitrogen into the planktonic food web of Massachusetts Bay natural stable isotopic tracers. On a day to day basis, much of the work in my lab centers on preparing samples for, maintaining, and running the lab mass spectrometers, but this routine is broken up nicely by research cruises which take us out to sea for anywhere between 2 and 5 weeks at a time.