David Fike
Graduate Student in Geobiology (Geochemistry)

Department of Earth, Atmospheric, & Planetary Sciences
Massachusetts Institute of Technology
77 Massachusetts Ave., 54-812
Cambridge, MA 02139

Phone: (617) 335-6372
E-Mail: dfike@mit.edu

My research focuses on the interplay between evolutionary and environmental change that is recorded by changes in redox conditions and biogeochemical cycling.  I am interested in using stable isotope (and other geochemical) proxies to probe these relationships.  For my thesis, I focused on the Ediacaran Period (~635 – 542 million years ago), using a combination of carbon and sulfur isotopes, supplemented by trace element abundances and organic biomarkers.  This suite of data allowed me to identify progressive stages of ocean oxidation and correlate them to pulses of biological evolution.  Further, the high-resolution dataset that resulted enabled me to develop quantitative models to describe the dynamic carbon and sulfur cycling that characterized Ediacaran time.  

Brief descriptions of several research areas are below:

Evolution and Environmental Change
I am interested in examining geochemical change over periods of intense evolutionary radiation (and also of apparent evolutionary stagnation) to illuminate the causal relationship that links evolutionary and environmental change.  Likely candidates for these high-resolution studies include the Cambrian of Morocco (with Professor Adam Maloof at Princeton) and the Ediacaran-Cambrian of Australia , in collaboration with Professor Roger Summons at MIT.

Isotope Modeling
While at MIT, I was encouraged by the work of Dan Rothman et al. to apply several novel approaches to understanding the carbon and sulfur (and nitrogen, shortly!) biogeochemical cycles.  Using paired isotope measurements (&delta¹³C_carb, &delta¹³C_org, &delta³⁴S_SO4, &delta³⁴S_pyr), I have developed new ways to quantify changes to biogeochemical cycles operating in both steady-state and non-steady-state modes.  Compiled data suggest the latter is the more common mode for global biogeochemical cycles to operate, at least over the interval of many chemostratigraphic studies. 

Mars
During my graduate work, I was fortunate to be able to be part of the Athena Science team as a participating student for NASA's Mars Exploration Rovers.  The discovery of sulfate evaporites on Meridiani Planum by the Opportunity Rover allowed me to combine my interests in planetary science with a portion of my doctorate that examined sulfate evaporites in the Sultanate of Oman.  In the future, I hope to continue my involvement in NASA's exploration of the solar system, analyzing geochemical data that is sent back to Earth and participating in studies of terrestrial 'Mars analog' environments.