James Farquhar



For the past 10 years, my research has focused on a variety of questions that are broadly connected to sulfur isotopes as well as systems that extend beyond sulfur. Components of our research has focused on (names of former and present group members and close collaborators with these foci listed in parentheses):


The Geological Record


Atmospheric evolution

(Johnston, Zerkle, Eldridge, Harms, Zhelezinskaia)

Sulfide deposits

(Jamieson, Kim, Wing)


Sulfur Cycling in Biological Systems


Metabolic transformations of sulfur

(Johnston, Wing, Zerkle, Oduro, Banker, Hoek)

Using sulfur isotopes to constrain cycling of sulfur in modern systems

lakes, marshes, hydrothermal pools, and sulfidic basins

(Johnston, Zerkle, Kamyshny, Oduro, Hoek, Wu, Mansaray)

Developing tools to investigate the antiquity of biological processes

(Johnston, Wing, Zerkle)

Organic sulfur compounds with an emphasis on DMS and DMSP


Isotope effects - exchange reactions, aqueous oxidation reactions, MIE

(Kim, Eldridge, Kim, Oduro, Harms)




Martian Meteorites

(Franz, Kim)

Composition of juvenile sulfur in solar system materials

(lunar samples, iron meteorites, basaltic achondrites)

(Wing, Antonelli, Franz, Kim, Peters)

Low temperature phases and weathering in meteorites

(Tyra, Franz, Kim)



Atmospheric applications


Atmospheric deposition (environmental studies of nitrate and sulfate)

(Cooney, Wu)

Experimental studies of photochemical mass-independent isotope effects

(Wing, Masterson, Franz)