COG3 Seminar: Ruth Varner (University of New Hampshire)

Ruth Varner (University of New Hampshire)
Friday, March 2, 2018 - 10:00am to 11:00am

From Archaea to the Atmosphere: Scaling isotopic emissions and microbes across a permafrost thaw landscape

High latitude peatlands are a significant source of atmospheric methane. This source is spatially and temporally heterogeneous, resulting in a wide range of emission estimates for the atmospheric budget. Increasing atmospheric temperatures are causing degradation of underlying permafrost, creating changes in surface soil moisture, the surface and sub-surface hydrological patterns, vegetation and microbial communities, but the consequences to rates and magnitudes of methane production and emissions are poorly accounted for in global budgets. We combine field observations, multi-source remote sensing data and biogeochemical modeling to predict methane dynamics, including the fraction derived from hydrogenotrophic versus acetoclastic microbial methanogenesis across Stordalen mire, a heterogeneous discontinuous permafrost wetland located in northernmost Sweden. Model simulated methanogenic pathways correlate with sequence-based observations of methanogen community composition in samples collected from across the permafrost thaw landscape. This approach enables us to link below ground microbial community composition with emissions and indicates a potential for scaling across broad areas of the Arctic region.

About the Speaker

Ruth Varner is a Professor of Biogeochemistry in the Earth Systems Research Center of the Institute for the Study of Earth, Oceans, and Space, and in the Department of Earth Sciences. She is also the Director of the Earth Systems Research Center and the Joan and James Leitzel Center for Mathematics, Science, and Engineering Education at the University of New Hampshire. She received a B.S. in Geology from Hartwick College in 1991, an M.S. in Hydrology (1993, UNH) and a Ph.D. in Geochemical Systems (2000, UNH). In recognition of her excellence in research and mentoring, Ruth was awarded the Elizabeth Sulzman Award from the Biogeosciences section of the American Geophysical Union in 2015. At UNH, Ruth was recently awarded the UNH’s Faculty Excellence award for the 2016 Outstanding Associate Professor and has also received the Class of 1940 Professorship for 2016-2018.

Her research experience at UNH began with developing a gas chromatography/cryo-focusing technique to quantify methyl bromide in ambient air samples. This work led to the discovery of soil as a significant biological sink of atmospheric methyl bromide. This research also led to the discovery of freshwater wetlands as a source of methyl bromide and methyl chloride to the atmosphere. Her work at UNH also includes carbon dioxide, methane and nitrous oxide exchange using autochamber technology in terrestrial ecosystems: boreal (BOREAS, NASA), temperate and tropical forests (LBA, NASA). Currently, her research focus is on the measurement of trace gas emissions from agricultural, temperate wetland and permafrost ecosystems with funded projects from the USDA, NSF, and NASA ABoVE. Ruth is also the former Director of the Northern Ecosystems Research for Undergraduates program, an NSF funded REU site.

About this Seminar

The Chemical Oceanography, Geology, Geochemistry, and Geobiology Seminar [COG3] is a student-run seminar series. Topics include chemical oceanography, geology, geochemistry, and geobiology. The seminars take place on Fridays from 10-11am in Building E25, Room 119, unless otherwise noted (term-time only).