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Welcome!

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Photo credit: Sophie Lheraud

 

I am a geobiologist. I am driven to understand how microbial metabolisms shape global biogeochemical cycles through time. I view the co-evolution of the geosphere and the biosphere – more specifically that of sedimentary environments and microbial communities – as a composite of three components: environmental conditions, microbial physiology, and enzyme kinetics. I strive to understand the nature of this co-evolution over time and quantify the relative contributions of these components to geochemical records and global biogeochemical cycles. I apply sophisticated microbial isotope models that incorporate enzyme isotope effects modulated by physiology and environment. I calibrate these with molecular-level models, in vitro enzyme work, microbial experiments, environmental observables, and geochemical records.

So far, I have focused on microbial metabolisms that drive cycles essential to the establishment of Earth surface conditions: (1) microbial sulfate reduction (MSR) and microbial sulfur disproportionation (MSD), which are both central to the sulfur (S) cycle and couple S to carbon cycling and organic carbon burial, and (2) biological nitrogen fixation (BNF), which is essential to the nitrogen (N) cycle and is a crucial ecological innovation in Earth history.

You can find a complete C.V. here, and highlights below: CV_EmmaBertran

 

Contact

Email: ebertran [at] princeton [dot] edu

Twitter: [at]emma_bertran

Current mailing address:

Department of Geosciences,

Guyot Hall, Princeton University

Princeton, NJ 08544

 

EDUCATION AND TRAINING

2019  Postdoctoral Fellow, Department of Geosciences, Princeton University.                    

Project: In vitro quantification of the enzyme nitrogenase nitrogen isotope effect and contribution to net biological nitrogen fixation.

Advisor: Dr. Xinning Zhang

 2019  Ph.D. in Earth and Planetary Sciences, Harvard University.

Thesis: Cellular and intracellular insights into the main drivers of biogeochemical sulfur cycling: microbial sulfate reduction and sulfur disproportionation

Faculty Advisor: Prof. David T. Johnston

2014  M.S. in Earth Sciences, McGill University.

Thesis: Deconstructing the Dissimilatory Sulfate Reduction Pathway: Isotope Fractionation of a Mutant Unable of Growth on Sulfate

Faculty Advisor: Prof. Boswell Wing

2010  B.S. in Biology with a minor in Geology, McGill University.

PUBLICATIONS AND PRESENTATIONS

Bertran, E., Ward, L. M., Johnston, D. T. (2020) Draft genome sequence of Desulfobacter hydrogenophilus DSM3380, a psychrotolerant sulfate reducing bacterium Microbiology Resource Annoucements

Ward, L. M., Bertran, E., Johnston, D. T. (2020) Draft genome sequence of Desulfovibrio sulfodismutans ThAc01, a heterotrophic sulfur disproportionating member of the Desulfotobacterota Microbiology Resource Annoucements

Bertran E., Waldeck A., Wing B. A., Halevy I., Leavitt W. D., Bradley A. S., Johnston D. T. (2020) Oxygen isotope effects during microbial sulfate reduction: applications to sediment cell abundances The ISME Journal 

Bertran E., Ward L. M., Johnston D. T. (2020) Draft genome sequence of Desulfofundulus thermobenzoicus subsp. thermosyntrophicus DSM 14055, a moderately thermophilic sulfate reducer Microbiology Resource Annoucements

Bertran E., Ward L. M., Johnston D. T. (2020) Draft genome sequence of Acidianus ambivalens DSM 3772, an aerobic thermoacidophilic sulfur disproportionator Microbiology Resource Annoucements

Waldeck A.R., Cowie B.R., Bertran E., Wing B.A., Halevy I., Johnston D.T. (2019) Deciphering the atmospheric signal in marine sulfate oxygen isotope composition EPSL

Bertran E., Leavitt W. D., Pèllerin A., Zane G. M., Wall J. D., Johnston D. T., Wing B. A. (2018) Deconstructing the dissimilatory sulfate reduction pathway: Isotope fractionation of a mutant unable to grow on sulfate Frontiers in Microbiology 

In press

Ward L. M., Bertran E., Johnston D. T. (2020) Genomic sequence analysis of Dissulfurirhabdus thermomarina SH388 and proposed reassignment to Dissulfurirhabdaceae fam. nov. Microbial Genomics

Ongoing work

Bertran E., Ward L. M., Kaçar B., Johnston D. T. Structural argument for the uniqueness of microbial sulfur disproportionation (in prep)

Bertran E. and Johnston D. T. Intracellular dynamics of sulfite and thiosulfate disproportionation: Insights from a thermodynamically rooted, isotope effect-calibrated model (in prep)

Bertran E., Ward L. M., and Johnston D. T. The Desulfobulbaceae family (in prep)

Invited Talks

Unique approaches for unique insights into the sedimentary biogeochemical sulfur cycle: Understanding the reductive and oxidative branches COG3 Seminar Series, Massachusetts Institute of Technology, Boston, Massachusetts, United States, 2019

Unique approaches for unique insights into the sedimentary biogeochemical sulfur cycle: Understanding the reductive and oxidative branches Division of Biology and Paleo Environment Seminar Series, Lamont-Doherty Earth Observatory, New York, United States, 2019

Conference Talks

Bertran E., Waldeck A., Wing B. A., Halevy I., Leavitt W. D., Bradley A. S., Johnston D. T. A mechanistic understanding of oxygen isotope effects during microbial sulfate reduction Goldschmidt Conference, Boston, Massachusetts, United States, 2018

Bertran E., Waldeck A., Wing B. A., Halevy I., Leavitt W. D., Bradley A. S., Johnston D. T. A mechanistic understanding of oxygen isotope effects during microbial sulfate reduction Geobiology Gordon Research Seminar, Galveston, Texas, United States, 2018

Bertran E., Waldeck A., Wing B. A., Halevy I., Leavitt W. D., Bradley A. S., Johnston D. T. A mechanistic understanding of oxygen isotope effects during microbial sulfate reduction Northeastern Geobiology Symposium, Woods Hole Oceanographic Institute, Woods Hole, Massachusetts, United States, 2018

Bertran E., Waldeck A., Wing B. A., Halevy I., Leavitt W. D., Bradley A. S., Johnston D. T. A mechanistic understanding of oxygen isotope effects during microbial sulfate reduction 5th International Symposium on Microbial Sulfur Metabolism, Vienna, Austria, 2018