I am a geobiologist. I explore the nature of the interaction between microbial life and earth. Such interactions leave specific chemical signatures that record information on microbial activity, and the environment the microbial communities saw during growth.
My goal is to interpret these signatures to reconstruct an accurate picture of paleo-environments and microbial communities, and their co-evolution through time. To date, I have focused on the sedimentary biogeochemical sulfur cycle and its main metabolic pathways: microbial sulfate reduction and microbial sulfur disproportionation. The extensive record of sedimentary sulfate and sulfide isotopic compositions tracks the evolution of Earth’s surface redox conditions and, by extension, the nature of the sedimentary sulfur biogeochemical cycle. The latter is carried out by a myriad of isotopically selective metabolic pathways that drive its reductive and oxidative branches. Microbial sulfate reduction runs the reductive sulfur cycle, while microbial sulfur disproportionation and microbial sulfide oxidation carry out its oxidative counterpart. Deconstructing the net preserved isotopic signature into its individual metabolic components requires a thorough understanding of the biochemistry of each, and of the environmental information enclosed in their specific sulfur isotopic signatures.
Email: emmabertran [at] fas [dot] harvard [dot] edu
Current mailing address:
Department of Earth and Planetary Sciences, Harvard University
20 Oxford Street, Cambridge, MA 02138