Research Overview

Research Overview

The Leigh Lab investigates the role of microorganisms in the biodegradation of environmental contaminants and in biogeochemical cycling. Our research topics include biodegradation of oil and dispersants in Arctic seawater, biodegradation of groundwater contaminants (e.g. sulfolane), the use of plants and microbes to remediate contaminated soils (phytoremediation), methane oxidation in Arctic lakes, and boreal forest ecology. We also organize efforts to foster collaboration between the environmental sciences, arts, and humanities, produces art-science exhibits and performances for the public, and conduct collaborative research on the impacts of these activities on audiences.

Phytochemical controls on boreal forest carbon cycling

Phytochemical controls on boreal forest carbon cycling

 

 

Through field studies at a common tree garden at Kevo Subarctic Research Station near Utsjoki, Finland (managed by the University of Turku), we’re investigating the role of plant secondary compounds in controlling soil microbial processes such as litter decomposition and contaminant biodegradation. Multi-year studies are in progress to understand the soil microbial ecology and litter decomposition of plants with different levels of secondary compounds due to different evolutionary histories of herbivore pressure (e.g. birch from Iceland, Finland, Siberia, and Alaska). We hypothesize that high concentrations of secondary compounds inhibit litter decomposition and build soil C stocks, while also selecting for microbes that target aromatic compounds, which could enhance contaminant biodegradation potential. We’re using next-generation DNA sequencing and stable isotope probing methods to characterize differences in microbial communities, genes, and functions.

The Broader Impacts components of this project includes a major arts-humanities-science exhibit, In a Time of Change: Microbial Worlds.  The exhibit features works created by artist-in-residence Stephanie Rae Dixon (Brooklyn, NY) who joined our research team in Finland, as well as 12 Alaska-based artists and writers working on a variety of other microbiological themes.

Financial support was provided by a grant from the National Science Foundation   DEB-1257424. Additional support was provided by Institutional Development Awards (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20GM103395, from the National Center for Research Resources (NCRR) under grant number 5P20RR016466, from the Ministry of Education, Youth and Sports of the Czech Republic no. LH 14004, and from the Czech Science Foundation under grant number 13-28283S.

Biodegradation of sulfolane in contaminated groundwater

Biodegradation of sulfolane in contaminated groundwater

The second largest contaminated site in Alaska resides beneath the city of North Pole, where hundreds of private drinking water wells have been contaminated with the industrial solvent sulfolane. In collaboration with David Barnes (UAF Institute of Northern Engineering) and Jan Sunner (University of Oklahoma), we’re working to assess biodegradation rates, groundwater flow patterns in discontinuous permafrost, to identify organisms and processes responsible for biodegradation, and to investigate the safety and efficacy of various cleanup systems including household drinking water filtration units.

Funded has been provided by the Alaska Department of Environmental Conservation, Alaska INBRE and USGS NIWR, as well as several URSA grants to support undergraduate research and through fellowship to Ph.D. student Chris Kasanke from Alaska INBRE.

 

Undergraduate researcher Michael Willis collecting groundwater samples

 

Press

Press

Links to recent press and videos featuring our work.

Phytoremediation of petroleum-contaminated soils

Phytoremediation of petroleum-contaminated soils

We’re working to assess the effectiveness and understand the mechanisms underlying phytoremediation (rhizoremediation), the use of plants and associated microbes, for cleanup of petroleum-contaminated soils in Alaska with a focus on rural communities. This includes advanced molecular genetic work on microbial communities, studies of biodegradation processes, plant natural product chemistry, contaminant analyses, and ecological assessments of contaminated sites. We’re also working closely with rural community members to find ways to improve local environmental self-determination, including identifying strategies that foster local engagement, employment, and economic benefit of cleanup activities.

By working closely with regulators (Alaska Department of Environmental Conservation), we initiated a long-term experimental/demonstration site in the rural community of Kaltag, AK, to remediate soil heavily contaminated with diesel that has been relocated from the schoolyard. If successful, this phytoremediation approach may be applied to many other sites across the state.

Funding for this research has been provided by the Alaska Department of Environmental Conservation, Alaska INBRE, USGS NIWR, the Czech Ministry of Education, the UAF BLaST Program, and the National Science Foundation.

Oil spills and spill response chemicals in the Alaska marine environment

Oil spills and spill response chemicals in the Alaska marine environment

 

As the risk of oil spills increases in Alaskan waters, there is a growing need to understand the biodegradation of petroleum as well as the fate and effects of oil spill response products. We are conducting laboratory incubation studies using Arctic (Chukchi Sea) and sub-Arctic (Prince William Sound) seawater as well as the Arctic benthos to assess oil degradation rates and to identify microbial taxa important to biodegradation. We are also investigating two spill response products on the National Contingency Plan (NCP) Schedule that are eligible for use in Alaskan waters and elsewhere: the chemical dispersant Corexit 9500A and Oil Spill Eater II (OSEII), a product marketed as an enzymatic biodegradation agent. Our goals include assessing the degradation of the major surfactant components of Corexit 9500A (with collaborator Jennifer Field of Oregon State University) and characterizing the composition and effectiveness of the lesser-known product OSEII. Because spilled oil can also become entrained in sediments, we are investigating the biodegradation of oil under aerobic and anaerobic conditions in Arctic sediment mesocosms as well. Using molecular microbial community analyses (e.g. 16S rRNA gene sequencing, metagenomics, and metatranscriptomics), we are characterizing shifts in community structure following exposure to oil and/or dispersants to identify taxa important to the biodegradation of petroleum and spill response products in the Alaskan marine environment. Through these studies, we aim to provide fundamental insight into Alaskan marine microbial ecology and to provide timely information to regulators, the oil spill response community, industry, and other stakeholders regarding the fate and effects of oil and spill response products in preparation for future oil spills.

These projects are funded by the Oil Spill Recovery Institute (Cordova, AK),   Alaska INBRE, the Bureau of Ocean Energy Management (BOEM) Coastal Marine Institute and previously by private industry (Shell, ConocoPhillips, Statoil, Alaska Clean Seas) and a Fulbright Award to Thailand.

 

Current research on oil spill response chemicals is in collaboration with Co-PI Dr. Ursel Schuette, Research Scientist, Institute of Arctic Biology, UAF.

 

Former Ph.D student Kelly McFarlin

 

Ph.D. student Taylor Gofstein

PI Leigh with UIC Science Boat Captain Vernon Brower, Utqiagvik (formerly Barrow), AK