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Welcome to the Zhang Geomicrobiology and Biogeochemistry Lab

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.

Opportunities for microbe lovers at both graduate and post-doc levels are available!  Postdoc positions are available for benthic N2 fixation, methane,and alternative nitrogenase related projects.  Undergrads interested in gaining research experience should take a look at summer internships in the Zhang lab funded by the Princeton Environment Institute (see 

Please contact for more information.

Contact Information:
Princeton University, Department of Geosciences, M47 Guyot Hall, Princeton NJ 08544
Phone:  (609) 258-2489


Laboratory News

Wednesday, Sep 11, 2019

Researchers in the Zhang Lab began their...

Friday, Aug 9, 2019

Meet the Zhang Group summer interns!

Recent Publications

  • The Siderophore Metabolome of Azotobacter vinelandii

    O. Baars; X. Zhang; F. M.M. Morel; M. R. Seyedsayamdost
    Journal Article

    In this study, we performed a detailed characterization of the siderophore metabolome, or “chelome,” of the agriculturally important and widely studied model organism Azotobacter vinelandii. Using a new high-resolution liquid chromatography-mass spectrometry (LC-MS) approach, we found over 35 metal-binding secondary metabolites, indicative of a...

  • Selenium controls transcription of paralogous formate dehydrogenase genes in the termite gut acetogen, Treponema primitia

    Eric G. Matson; X. Zhang; Jared R. Leadbetter
    Journal Article

    The termite gut spirochete,Treponema primitia,isaCO2-reductive acetogen that is phylogeneticallydistinct from other distantly related and moreextensively studied acetogens such asMoorella ther-moacetica. Research onT. primitiahas revealeddetails about the role of spirochetes in CO2-reductiveacetogenesis, a process important to the...

  • The purple non-sulfur bacterium Rhodopseudomonas palustris produces novel petrobactin related siderophores under aerobic and anaerobic conditions

    O. Baars; F. M.M. Morel; X. Zhang
    Journal Article

    Many bacteria produce siderophores to bind and take up Fe(III), an essential trace metal with extremely low solubility in oxygenated environments at circumneutral pH. The purple non‐sulfur bacterium Rhodopseudomonas palustris str. CGA009 is a metabolically versatile model organism with high iron requirements that is able to grow under aerobic...