Jena E. Johnson
Principal Investigator [CV]
I have long been fascinated by how the history and evolution of life on Earth are tied to the evolving climate and surface chemistry of our planet. I majored in Geobiology at Brown University and pursued a PhD in Geobiology at Caltech. My PhD investigated the evolution of photosynthesis and rise of atmospheric oxygen through the manganese mineral record. During the course of my thesis, I recognized the importance of performing laboratory experiments and studying field analogues in order to correctly interpret the rock record. I continued gaining expertise in linking aquatic chemistry with geomicrobiology in a postdoctoral position at the University of Colorado in Boulder. I began a faculty position in the Earth and Environmental Sciences department at U-Michigan in January, 2018.
Here at Michigan, I am focused on understanding how the evolution of life and environments are recorded in chemical signals safeguarded in the geologic record. We are beginning projects to understand the potential geobiological signals hosted in chemical precipitates in the sedimentary record, and studying microbe-mineral interactions that could lead to the formation of these ancient geobiological signals.
Current Lab Members
Isaac has been working with Jena since May 2017 on understanding the origin of iron silicate minerals in the rock record. After completing his honors thesis at the University of Colorado under the guidance of Jena and Alexis Templeton (CU-Boulder), Isaac has begun his role as the Microbe-Mineral lab manager at U-Mich in August, 2018! In addition to keeping the lab running, Isaac will be continuing his work on identifying potential biosignatures of microbially-mediated iron silicate precipitation.
Joining the Microbe-Mineral Lab in Aug, 2019, Alice is exploring whether photoferrotrophy can catalyze the precipitation of iron silicates and determining whether there are potential signatures of that biomediation using a variety of spectroscopic and transmission electron microscopy methods. This research will allow us to understand whether photoferrotrophy was involved in the formation of iron formations. She joins us from Dartmouth College where she obtained her M.S. degree working on extremophilic archaea and what exactly their preservable membrane lipids record about their activity.
Chrissie joined the Microbe-Mineral Lab in Aug, 2019, to investigate the products of microbial iron reduction in a silica-rich environment (like potential reactions during the early diagenesis of iron formation sediments) using transmission electron microscopy and Raman spectroscopy. She previously worked on elemental sulfur storage in bacteria and the silicification of organic-sulfur filaments at Penn State.
After finishing her senior honors thesis in the Microbe-Mineral Lab, Sammy is continuing to work on understanding how differences in the proportions of Fe(II) and Fe(III) in silica-rich but oxygen-free water leads to the precipitation of different iron minerals. She uses colorimetric assays and infrared and Raman spectroscopy to analyze her precipitates. Her driving passion is to compare her synthetic iron clays with similar minerals on ancient Mars and early Earth!