Research in the Wilkins Lab is focused on understanding the linkages and feedbacks between microbial populations and biogeochemical processes across a range of subsurface systems. Our work encompasses everything from physiological interrogations of microbial pure cultures to multi-omics investigations of microbial assemblages sampled from the field. We couple these microbial analyses to geochemical and hydrologic datasets to enable a more complete understanding of subsurface biogeochemistry
Linking biogeochemistry and hydrology
The East River outside of Crested Butte, western Colorado (Photo credit: Lawrence Berkeley National Laboratory)
Just outside of Crested Butte, CO, the East River catchment represents a pristine upland watershed where our research team – in collaboration with scientists at the Lawrence Berkeley National Laboratory and other researchers in the School of Earth Sciences here at OSU – is investigating linkages between seasonal hydrology and biogeochemical processes in the riverbed. This ecosystem is a hotspot of microbial activity in upland catchments, with implications for solute transformations and export from the watershed. Via an award from the US Department of Energy, we are coupling high resolution microbial analyses (metagenomics) with geochemical and hydrologic tools to better understand how the microbiome in the riverbed hyporheic zone responds to seasonal changes in the extent of down-welling river water and up-welling groundwater.
Deep shale biogeochemistry
Moving deeper into the subsurface, we are currently studying how bacteria interact with their environment in deep shale environments. Much of eastern Ohio is underlain by the Marcellus and Utica shale formations, and is currently the focus of intensive energy extraction. Work by our group – in collaboration with the Wrighton Lab at OSU and the Mouser Lab at the University of New Hampshire has revealed the development of microbial communities following hydraulic fracturing in the shales. The Wilkins Lab is using high-pressure incubation apparatus to simulate in situ conditions in the laboratory to study key isolated microorganisms. Enrichments and isolations are coupled with genomic tools to understand how shale-dwelling microbial populations develop and persist in hydraulically fractured shale formations.
A site in eastern Ohio undergoing hydraulic fracturing
Critical redox processes in wetland soils and sediments
We are also interested in biogeochemical cycling in prairie pothole wetlands in the upper Midwest US, and southern Canada. Many of these wetland systems contain extremely high levels of dissolved organic carbon and sulfur species, making them ideal places to study linkages between the carbon and sulfur cycles. Work by our group has revealed extremely high rates of microbial activity in these systems, resulting in large methane fluxes to the atmosphere. Current work is assessing the role that microbial viruses and reactive oxygen species play in ecosystem functioning.
Prairie pothole lake outside of Jamestown, ND
Metal transformations in aquifer systems
Metal contamination (both anthropogenic and natural) is a critical issue affecting water quality worldwide. Our research team is working in systems affected by human mining activities (uranium in Colorado) and natural metal mobilization (arsenic in Ohio) to understand the microbial potential for metal transformations and determine strategies for bioremediation where appropriate.