People in the geomicrobiology group at Appalachian State University
We are an interdisciplinary team of scientists from Appalachian State University, the United States Geological Survey, and other universities in the US. Suzanna Brauer (Biology) and Sarah Carmichael (Geological and Environmental Sciences) are the group's main advisors and administrators.
Primary Faculty
Suzanna Bräuer is a Professor in the Department of Biology at Appalachian State University. She is a microbiologist whose work includes microbial ecology of cave systems (particularly manganese oxidizing bacterial communities), the role of anthropogenic impact on microbial communities, and microbial methane production in peat bogs.
Sarah Carmichael is a Professor in the Department of Geological and Environmental Sciences at Appalachian State University. She studies the mineralogy of manganese ore deposits and the characteristics of manganese biominerals in caves, in addition to her work on cave sediment characterization and the geochemistry of mass extinctions. Her research heavily involves scanning and transmission electron microscopy, X-ray diffraction, and spectroscopic techniques.
Collaborators
Yongli Gao is an Associate Professor in the Department of Geological Sciences at the University of Texas at San Antonio. He is a karst hydrogeologist who specializes in basin-scale hydrologic simulations, sinkhole hazards, and paleoclimate and environmental reconstruction through speleothem geochemistry.
Cara Santelli is an Associate Professor in the Department of Earth Sciences at the University of Minnesota, after spending many years as a Research Geologist and Curator in the Department of Mineral Sciences at the Smithsonian Institution’s National Museum of Natural History. Her work examines the impact of microbial activity on a wide variety of geological processes such as biomineralization and weathering, metal redox transformations, fungal biomineralization processes, environmental geochemistry, and remediation of sites impacted by acid mine drainage pollution.
Students
Students (both graduate and undergraduate) form an integral part of our research team, and are responsible for performing a wide variety of analyses.
Current Students
Former Students
(M.S. Biology - 2012)
MS Thesis Title: Geomicrobiology of Ferromanganese Deposits in Caves of the Upper Tennessee River Basin
Mary Jane received her Ph.D. in Biology from Wake Forest University in 2017, and is now an Assistant Professor of Biology at Hollins University.
She won Appalachian State University's 2013 Cratis Williams Thesis Award, and the American Association of University Women's 2016-2017 AAUW Dissertation Fellowship.
(M.S. Biology - 2016)
MS Thesis Title: Microbial Community Analysis Coupled With Geochemical Studies Reveal Factors Affecting Biotic Mn (II) Oxidation In Situ
Mara recently completed her Ph.D. in Soil Science from Penn State University. She is currently a Project Manager and Scientist at the Soil Health Institute.
(B.S. Geology - 2015)
Josh is now a Professional Geologist (P.G.) who runs his own company, NaturalGeodata, in Henderson County, NC.
(M.S. Biology - 2012)
Bryce's MS investigated the relationship between microbes and sediment chemistry across anthropogenically impacted caves and pristine caves, to see what role that sediment geochemistry vs human impact played in supporting Mn oxidation in cave sediments.
MS Thesis Title: The effects of substrate geochemistry on the distribution of manganese oxidizing bacteria in caves of the Upper Tennesee River Basin
(M.S. Biology - 2024)
For her MS in Biology, Anna-Maria studied the impact of human traffic and artificial lighting on microbial communities in show caves in the southern Appalachians, and performed preliminary microplastics analyses across show caves vs. pristine caves.
MS Thesis Title: Human impact in Appalachian cave systems: How anthropogenic presence leads to the deposition of microplastics and alteration of native microbial cave communities
(B.S. Geology - 2012)
BS Thesis Title: Manganese Oxidation by Fungi in Karst Environments
Leigh Anne is currently working as a hydrogeologist with the Department of Health and Environmental Control in Columbia, South Carolina after receiving her M.S. in Geochemistry at the University of Maryland in 2014.
(M.S. Biology - 2020)
MS Thesis Title: The comparison of manganese (II) oxidizing microbes in two cave systems
Morgan's work on the role of manganese oxidation on different mineral substrates was severely interrupted by COVID-19 lab closures, but instead she found that cave microbial communities were far more varied than we had previously anticipated. She now works as a Laboratories Manager for Stallergenes Greer.





















