How have microbes shaped and been shaped by evolving environments throughout Earth history?

I am an interdisciplinary geobiologist and geochemist with a deep curiosity about the feedbacks between the biosphere and the geosphere that have shaped the Earth. I am particularly interested in microbes – bacteria, archaea, and simple eukaryotes – which were the earliest forms of life and remain key components of our planet today. These organisms both shape and are shaped by the environment; they adapt and evolve in response to changes in the environment and, in parallel, contribute to chemical processes and geochemical cycles that shape the environment. However, we still do not have a complete understanding of the mechanisms and biological/chemical processes that underpin these interactions. My research centers around these microbial-environmental interactions and aims to better characterize how the biosphere and the environment have coevolved throughout Earth history.

The history of this coevolution is recorded both in the sedimentary and biosignature record and in modern microbes and environments. I use a field based, experimental, and microanalytical techniques (both microscopy and geochemistry) that tap into these modern and ancient records. With these tools, I hope to paint a more complete picture of the chemical conditions in ancient environments, the life that inhabited those environments, and the feedbacks between the biosphere and geosphere that shape the evolution of our planet. I am particularly interested in taphonomy – the study of the fossilization processes – and what taphonomy can tell us about ancient environments, early life, and the biological and abiotic processes that influence Earth system dynamics and evolution.

I have also extended my interests to the search for evidence of life outside of the Earth. On the Mars 2020 team, I became interested in understanding ancient environments on Mars, their past habitability, and their preservation potential. In my research, I continue to ask not only how we can identify and interpret biosignatures on Earth, but also how we will find evidence of past life on Mars, if it ever existed.