DeMMO is located in the former Homestake gold mine at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA.
The Homestake Mine was active between 1876 and 2001, reaching a depth of over 8100 ft (2469 m) below land surface, and producing
1,101 metric tons of gold. The site was donated to the state of South Dakota in 2006 and was ultimately developed into a dedicated
DeMMO is a series of boreholes within the facility that intersect fluid-filled fractures spanning depths of 800-4,850 feet.
SURF is hosted in heavily deformed, iron-rich, Paleoproterozoic metasediments that document oceanic volcanism and subsequent
infilling of the marine basin. Both the Precambrian age and iron-rich character of the rocks at SURF affect the chemistry of the
borehole fluids, contributing to the diverse array of microbial inhabitants.
In 2013 the NASA Astrobiology Institute Team Life Underground began work at SURF, characterizing geochemistry, microbiology, and redox
reaction energetics at key sites with an eye toward habitability. DeMMO was officially established in 2016, and routine sampling and
experiments are ongoing. Studies thus far have revealed distinct populations of subsurface microbes, many from wholly uncultivated lineages,
with interesting metabolic strategies tailored to subsurface, rock-associated habitats. Find out what we've learned in more detail by
exploring the links in the Projects section below.
People at DeMMO
DeMMO collaborators come from all over the world, including research groups from
Northwestern University, Desert Research Institute, University of Southern California,
Jet Propulsion Laboratory, and Bigelow Laboratory. Click on the images to learn more about the DeMMO team.
Dr. Maggie Osburn PI Northwestern University
Dr. Magdalena Osburn is a geobiologist interested in understanding interactions between microbes and Earth at DeMMO.
Her work is focused largely the gradient between shallow and deep subsurface environments.
DeMMO is a large and geochemically interesting environment that is particularly rich in novel taxa.
Dr. Osburn queries how microbes persist in this deep continental setting including to what extent they use materials from the geosphere vs. relying on carbon and oxidants from the surface.
Microbial dark matter, uncultivated and unclassified organisms only known from their DNA, constitute the vast diversity of microbial life on Earth and are particularly abundant at DeMMO.
The development of novel cultivation techniques both in the lab and at DeMMO help to understand why these microbes are so hard to grow and ultimately, growing them is a key feature of Osburn lab activity at the moment.
She uses micro-scale imaging and DNA sequencing to identify organisms, reconstruct their genomes, and see how they interact with minerals and one another.
Dr. Osburn is additionally interested in developing lipid biomarker and isotopic approaches to understand biological information preserved in rocks over geological timescales.
Caitlin Casar PhD Candidate Northwestern University
Caitlin is a member of Prof. Maggie Osburn's Isotope Geobiology Lab.
She has been visiting DeMMO regularly since 2016 to collect frature fluids
to monitor fluid chemistry and microbial community composition over time. She deploys
in situ cultivation experiments targeting the rock-hosted biofilm communities at DeMMO.
She uses scanning electron microscopy, 16s rRNA gene amplicon sequencing, and thermodynamic modeling
to characterize biofilm community composition, biomass, and metabolic function.
She carries out lab-based cultivation experiments with minerals to isolate members of the biofilms.
Dr. Lily Momper Postdoctoral Scholar Northwestern University
The major goal of Lily's research is understanding how microbes impact biogeochemical cycling at various spatial and temporal scales
in the terrestrial subsurface. To unravel this complex topic she uses tools such as full genome metagenomic sequencing and aqueous
geochemical analyses. Specifically, she looks at assembled metagenomic DNA from the DeMMO site fluids and reconstruct individual
genomes from them. She can then interrogate the metabolically functional genes from the metagenomes, and the genomes on an individual
basis. Knowing the putative metabolisms and the concentrations of metabolically relevant geochemical species enables her to make predictions
about prevalent bacterial and ardchaeal metabolisms and how they might be interacting with the subsurface environment. This is particularly
exciting in the case of 'microbial dark matter,' microbes for which we have DNA evidence but no cultured representatives. Full or partial
genome sequencing of these uncultivated groups enables her to make predictions about their environmental and ecological role.
Caroline Webster Undergraduate Researcher Northwestern University
Caroline is a third year undergraduate student at Northwestern University studying Earth Science and Environmental Policy.
Since March 2019, she’s been in Prof. Osburn’s geobiology lab and working closely with Lily Momper,
cultivating microbial dark matter using genetically-informed targeted culturing techniques.
Dr. Andrew Masterson Senior Research Associate, IRMS Lab Manager Northwestern University
Dr. Andy Masterson is a Senior Research Associate in the Stable Isotope Facility at Northwestern University.
His work, and the SIF, support method development in Caitlin's DeMMO fluid sampling and anaerobic culturing
techniques, and analyze DeMMO samples for dissolved inorganic carbon and the stable carbon and nitrogen isotopes
of fluid-sourced and cultured biomass.
Dr. Fabrizio Sabba Postdoctoral Scholar Northwestern University
Fab joined the Osburn's Lab 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.
Dr. Brittany Kruger Field Coordinator Desert Research Institute
Dr. Kruger has been involved in the DeMMO effort since its conceptualization in 2015, working closely with Dr. Osburn to design and implement borehole modification and sampling strategies. She has also served as fieldwork coordinator since DeMMO’s establishment, organizing multi-researcher sampling teams and assisting in experiment installation and sample collection.