The Zhang laboratory seeks to understand microbial nutrient and energy transfer in past and present environments.  Our interdisciplinary approach, which draws inspiration from culture-based microbiology, molecular microbial ecology, and stable isotope geochemistry, is imbued by strong consideration of microbial metabolism at cellular and community scales and involves research in both laboratory and field settings.

Metalloproteins are a central theme in our research as they catalyze nearly all energy transfers in biology. Despite their importance, much remains to be understood about what controls metalloprotein activity in the environment. This fundamentally limits our ability to address changes in climate, elemental cycling, and the energy landscape. We believe that viewing metalloprotein activity in the context of broader metabolic fluxes within and between cells will aid in resolving long-standing questions in microbial biogeochemistry.


Current investigations fall under the following areas:

-        Benthic marine N2 fixation, focusing on the physiological diversity and environmental sensitivities of nitrogen fixers inhabiting the vast benthic realm, relatively understudied compared to pelagic N2 fixation.  In a project generously funded by the Simons Foundation, we use culture and field studies to answer questions such as, "Why and when do benthic diazotrophs fix N2?"; "Are the environmental responses of benthic nitrogen fixers fundamentally different from pelagic nitrogen fixers?" ; "Does benthic N2 fixation contribute substantively to marine fixed N inventories? Will climate change alter this?"

 -       Biological nitrogen fixation by canonical Mo and alternative V, and Fe-only nitrogenase metalloenzymes, focusing on determining the distribution of and controls on the activity of different nitrogenases in modern and ancient ecosystems using model organisms and communities.

-       Microbial trace metal acquisition, focusing on how metal acquisition strategies are adapted to an organism’s environment and physiology.

 -       Hydrogen stable isotopes and microbial metabolism, focusing on (a) the environmental application of lipid hydrogen stable isotope measurements to reconstruct microbial metabolism and (b) the molecular basis of H fractionation in bacterial lipids and other macromolecular classes.

 -       Microbial methane cycling, focusing on how dynamic redox conditions affect methane emissions by altering the activity of key microbial functional groups in wetland systems.