Graduate Students

Caitlin Casar is a fifth-year PhD candidate interested in deep subsurface microbial ecology and its applications to astrobiology. She is currently exploring microbial life living in fracture fluids as deep as 4,850 feet at the Deep Mine Microbial Observatory (DeMMO) at the Sanford Underground Research Facility in Lead, South Dakota. This NESSF funded project focuses on characterization of mineral-hosted biofilm communities through field and laboratory-based cultivation experiments. In her spare time she enjoys coding, graphic design, and entertaining her two cats (Creme Fraiche and Neko). 

Matt Selensky is a graduate student currently researching the geomicrobiology of lava tube cave systems. As part of a NASA-led initiative to study lava tubes as potential havens for life on Mars, he is working to characterize the isotopic and lipid biomarkers of the cave microbial communities throughout Lava Beds National Monument, CA. He also hopes to understand the nutrient cycling present in such caves by performing isotopic labeling experiments in culture. Outside of the lab, Matt loves drawing, checking out concerts around Chicago, and running!

Niloufar Sarvian is a fourth year Ph.D. student in the Earth and Planetary Sciences department studying the causative mechanisms behind the Neoproterozoic Snowball Earth. She uses radiogenic and stable strontium isotopes to investigate the levers of the carbon cycle and the factors that contributed to a worldwide glaciation event. Her work with Maggie involves studying Ca and Sr fractionation in microbially precipitated carbonate rocks. In her spare time, Nilou enjoys playing sports, hanging with pups and learning how to play bass guitar.

Floyd Nichols is a second year PhD student studying lipid preservation in sulfate-dominated lakes in British Columbia. He is working to characterize and quantify lipids from sediment cores in these systems to better understand how biosignatures may have been preserved on Mars when water was present. He also hopes to understand sulfur cycling in these systems by using sulfur and oxygen stable isotopes. In his spare time, Floyd enjoys running, photography, cooking, birdwatching, and drinking coffee with senior citizens.

Undergraduate Students

Caroline Webster is a senior undergraduate focused on helping the Osburn lab grow novel microbes. In addition to her own culture collection Caroline is helping Maggie grown thermophiles and Caitlin characterize a novel species.

Post Doctoral Scholars

Dr. Fabrizio Sabba joined the Osburn’s Lab as a post doc in 2019. His research interests include biological processes for nutrients removal and resource recovery during water and wastewater treatment, with a focus on biofilm processes and N, P and S cycles. He obtained his Ph.D. in Environmental Engineering at the University of Notre Dame in 2017. Fab is involved in cultivating previously uncultivated members of the ‘microbial dark matter.’ He combines geochemical measurements and new genomic information with cultivation strategies to target these unusual groups.

Affiliated Staff

Dr. Andrew Masterson –  Research associate and IRMS lab manager-interested in sulfur isotope and marine biogeochemistry, mass-spectrometry, continuous flow method development, and precision baking.

Dr. Brittany Kruger has been affiliated with the Osburn Lab since 2015, working closely with Dr. Osburn to design and implement borehole modification and sampling strategies in subsurface locations. She has served as Dr. Osburn’s fieldwork coordinator at the Deep Mine Microbial Observatory (DeMMO) since its establishment, organizing multi-researcher sampling teams and assisting in experiment installation and sample collection. Her personal research interests include carbon cycling between the geologic and biologic carbon reservoirs in subsurface environments.


Hannah Dion-Kirschner gradated from Northwestern in 2019 and is currently a graduate student at Caltech. She is interested in using organic geochemistry and geobiology to understand Phanerozoic paleoclimate. Her undergraduate thesis sought to answer questions about Greenland’s Holocene climate using compound-specific isotopes of plant biomarkers. When she’s not in the lab or practicing her instrument, Hannah loves to go swing and blues dancing.

Sohyun Lee is a senior undergraduate student studying earth sciences and environmental policy & culture. Her research project examines lipids in lake sediments. Unfortunately, the challenges presented by Covid-19 have prevented the completion of her lab work in the Osburn Lab. In her free time, she likes to play the piano and take walks along the lake.

Dr. Lily Momper was a post doc working on deep subsurface biosphere questions and is now working in environmental consulting. One of the major obstacles to a clearer understanding of the earliest history of life on Earth is uncertainty in the timing of major biological events. Identifying the births and deaths of major gene pathways will help place those events in context of relevant geochemical events in Earth history, and conversely help to constrain the timing of those events. She uses a combination of culturing, bioinformatics and lipidomics to understand how microorganisms and geochemical conditions have co-evolved through Earth history.

Jamie McFarlin Received her Ph.D. in 2019 candidate dual-advised by Maggie Osburn and Yarrow Axford and is currently a post doc at UC Boulder. She works on reconstructing Quaternary interglacial climate in Greenland from lake records using coupled proxies, in particular chironomid-inferred temperature and compound-specific hydrogen isotopes. Her current focuses include an Eemian temperature and hydroclimate record in northwest Greenland and developing calibration data for modern leaf waxes along the western coast of Greenland. She enjoys sleeping at high latitudes in an orange tent during the summer, distance running, and bluegrass music.

Dana Johnston –  Former Undergraduate, interested in microbial ecology, environmental geochemistry, and dangerous field work. Dana is currently a graduate student at UW Madison studying the microbe-plants-soil system and it’s response to fire.