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Biogeochemistry and the Subsurface Biosphere

Our laboratory undertakes a number of studies of natural and built environments using genomic tools to describe microbial community functions, and geochemistry approaches to measure their consequences.

Serpentinite Biogeochemistry
Serpentinites represent a vector for the transport of deeply sourced carbon and reducing power from the mantle into the biosphere. Our ongoing work is tracking the composition and source of carbon-bearing compounds in marine and terrestrial serpentinizing environments, and the ways in which microbial populations impact the flux of these compounds. Recently, we have also examined sulfur biogeochemistry in serpentinites, as the transport of sulfur (and paleo-seawater) during the weather of oceanic crust and its' accretion onto the continents represents a mechanism connecting marine and terrestrial environments.

Biology meets Subduction
An international team of researchers, using seed funding from the Deep Carbon Observatory has studied the flux of volatiles (H2O, CO2, etc) from above subduction zones. Work in Central America showed that a substantial proportion of carbon previously assumed to be buried in the deep Earth was actually "trapped" in the forearc region. Ongoing work is investigating the links between volatiles and the deep biosphere in Central and South America.

Evolutionary Ecology in Extreme Environments

Extreme environments challenge microbial physiology by shaping adaptations to cope with variations in energy flow, nutrient acquisition, cell survival, and biomolecular repair. We investigate microbial adaptations to environmental extremes (pH, pressure, temperature) by studying naturally occurring extreme environments. We study how microbial interactions within these communities, including horizontal gene transfer shape genome composition and evolution. Further, we compare biotic and abiotic processes in these systems to develop reliable biosignatures to apply to both terrestrial (modern and early Earth) and extraterrestrial environments.

Groundwater Microbiology and Environmental Health

Extreme environments challenge microbial physiology by shaping adaptations to cope with variations in energy flow, nutrient acquisition, cell survival, and biomolecular repair. We investigate microbial adaptations to environmental extremes (pH, pressure, temperature) by studying naturally occurring extreme environments. We study how microbial interactions within these communities, including horizontal gene transfer shaping genome composition and evolution.

Saginaw Bay Septics
In rural areas, septic systems are a major mechanism of on-site wastewater treatment. However, in Michigan, there is no unified state-wide septic code and therefore these systems exist in various states of upkeep and regulation. The signatures of failing septic systems can overlap with our sources of environmental contamination such as agriculture, industry, and municipal wastewater overflow. Our work will combine high resolution microbiology and geochemical studies with detailed maps of septic systems in Bay County, MI to develop novel, high-fidelity indicators of septic field contamination. We will also study how septic field inputs impact local groundwater ecosystems.

Environmental Change and the Groundwater Microbiome
Groundwater flow pathways where water is exchanged between the Earth's surface and subsurface span from days to millennia. Microbial communities in groundwater adapt to both in situ conditions such as pressure, temperature, and oxidation-reduction potential (ORP) as well as perturbations at the Earth's surface such as contamination and land use changes. We are investigating the composition and function of groundwater microbial communities along shallow and deep flow pathways to explore how surface signals propagate and persist into the subsurface. The work will intensively sample aquifers of various depth of mid-Central Michigan to to explore these hypotheses.