Collaborative research: Geophysical evaluation of biogenic gasses in peatlands

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0510370 0510545 0510004Slater Glaser ReeveBiogenic gas emission from northern peatlands, by wicking from vascular plants and byepisodic ebullition events, accounts for approximately 7% of the global annual emissionof methane to the atmosphere. This proposal involves experiments to apply groundpenetrating radar (GPR) for (1) estimating the amount of biogenic gas stored in peatlands,(2) determining the spatial distribution of biogenic gas within the peat, and (3)monitoring biogenic gas release to the atmosphere. Data from a large northern peatland inMaine (EAR-0242353) show that (1) higher CH4 and CO2 concentrations correlate withhigh velocity/high attenuation zones in cross-borehole GPR data as well as shadow zones(loss of reflections) in surface GPR data, (2) shadow zones (indicative of high gascontent) are frequently observed in the +11 km of surface GPR data collected in thispeatland. The experimental objectives are: (1) a laboratory evaluation of the relationshipbetween dielectric permittivity and gas content for a profile of peat cores from the surfaceto the mineral soil; (2) a cross-hole GPR and surface GPR monitoring experiment,supported by measurements of water levels, hydraulic conductivity and time domainreflectometry, to observe rates of biogenic gas release to the atmosphere; (3) a surfaceGPR study, supported by in situ measurements of biogenic gas concentration, to estimatethe volume of biogenic gas stored in two well studied northern peatlands (Caribou Bog,ME and Glacial Lake Agassiz, MN). Important milestones include (a) a predictiveequation for gas content estimation in peat as a function of depth from dielectricpermittivity measurements, (b) new insight into the temporal pattern of gas release andebullition flux from peatlands, and (c) new estimates of the free gas content of peatlandcarbon reservoirs accounting for the spatial/depth distribution of the gas.Broader ImpactsThis proposal incorporates educational activities, curriculum development, communityoutreach and international collaboration within an applied research framework. HonorsUnderGraduate (HUG) researchers from the Rutgers-Newark Honors College (HC) willpartner with a postdoctoral scientist to obtain the research training required to completefour of the primary research tasks. Each HUG will complete a yearlong senior project ontheir research and contribute to a publication. The status of Rutgers-Newark as the toprankedNational US University with respect to campus UG diversity facilitates HUGopportunities to minority students. Students in Earth/Environmental Sciences at Rutgers-Newark frequently express interest in fieldwork experiences. Part of the fieldwork will beconducted by students participating in a new class, Summer Field Camp in AppliedGeophysics, developed as part of this project. Community outreach will occur via guidedtours, poster boards and presentations on the hydrology, ecology and carbon cycle inCaribou Bog, facilitated by the recently opened 2 km long Orono boardwalk that nowprovides public access to this bog. Finally, collaboration with a prominent peatlandscientist in Europe will draw international attention to our work and provide anopportunity to conduct comparative work on a unique European peat bog.