DSC_1838 Professor Sarah Stewart Johnson (PI)

I’m an assistant professor at Georgetown University and a visiting scientist at NASA’s Goddard Space Flight Center. I’m fortunate to get to work with some amazing people!  At present, my lab includes:

Elena Zaikova
I am a postdoctoral fellow investigating the evolution, adaptation and evidence of activity of microbial communities inhabiting extreme environments like Antarctica. My primary research interests lie in understanding how microbial communities assemble and function, and how they help shape the ecosystem.
unnamed Maëva Millan
I am a postdoctoral fellow working on the chemical and mineralogical composition of the Martian surface using the Sample Analysis at Mars (SAM) experiment onboard the Curiosity rover of the MSL mission. In particular, I am searching for organic molecules and biomarkers on Mars and investigating methods of their preservation in various kind of Martian minerals. In addition to data collected from SAM, I work with Martian analog samples from terrestrial environments. I recently received my Ph.D in specialty Astronomy and Astrophysics in France on a similar project. My daily laboratory experiments are physio-chemical analysis using pyrolysis and wet chemistry coupled to gas-chromatography mass-spectrometry. I try to replicate SAM conditions as closely as possible to help data interpretation and the search of organic matter. Besides work, I love hiking and taking pictures of the beautiful places, landscapes and people I meet during my trips.
DSC00351 Angela Bai
I am a fourth-year undergraduate studying Biology and Business Administration, and I research the ancient microbial communities of Antarctica’s Dry Valleys in order to understand how life can survive in extreme environments. I am fascinated by astrophysics, space, and the diverse paradigms for thinking about life in extraterrestrial contexts. Besides in Regents 511, I can also be found cooking with my Magis Row housemates or geeking out about design and innovation over chai lattes.
Ben Indo1 (1) Ben Johnson
I’m an undergraduate in my final year majoring in Human Science in the School of Nursing Studies. While not an environmental biologist, I make my home in the Johnson lab studying the effects that the prolonged isolation of spaceflight could have on the human microbiome through extraplanetary habitation simulations such as NASA’s HI-SEAS IV project. Hopefully, this will be able to give us a little more information about how to live on other planets safely. Much of the rest of my time is spent in uniform, driving an ambulance for Georgetown EMS or daydreaming about my next travel destination.
Screen Shot 2017-06-10 at 11.19.18 PM Maggie Weng
I am an undergraduate summer research student participating in the Georgetown REU in Environmental Science. I just finished my second year studying Environmental Earth Sciences and Creative Writing at Washington University in St. Louis. During the year I work for Dr. Ray Arvidson doing remote sensing and data analysis of the Martian surface. This summer I will be focusing on studying biosignatures of silica deposits in the Atacama Desert. I am interested in astrobiology and geobiology, including how organisms interact with and shape environmental cycles. When not working, I love writing and reading stories, hiking, and discovering new places.

Lab alums include:

deirdre savannah
Deirdre Collins


IMG_0354 savannah 2015-05-22 15.07.15
Monica Soni Savannah Fuqua Allee Torres