Collaborative research: Geophysical evaluation of biogenic gasses in peatlands

Biogenic gas emission from northern peatlands, by wicking from vascular plants and by episodic ebullition events, accounts for approximately 7% of the global annual emission of methane to the atmosphere. This proposal involves experiments to apply ground penetrating 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 in Maine (EAR-0242353) show that (1) higher CH4 and CO2 concentrations correlate with high 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 gas content) are frequently observed in the +11 km of surface GPR data collected in this peatland. The experimental objectives are: (1) a laboratory evaluation of the relationship between dielectric permittivity and gas content for a profile of peat cores from the surface to the mineral soil; (2) a cross-hole GPR and surface GPR monitoring experiment, supported by measurements of water levels, hydraulic conductivity and time domain reflectometry, to observe rates of biogenic gas release to the atmosphere; (3) a surface GPR study, supported by in situ measurements of biogenic gas concentration, to estimate the volume of biogenic gas stored in two well studied northern peatlands (Caribou Bog, ME and Glacial Lake Agassiz, MN). Important milestones include (a) a predictive equation for gas content estimation in peat as a function of depth from dielectric permittivity measurements, (b) new insight into the temporal pattern of gas release and ebullition flux from peatlands, and (c) new estimates of the free gas content of peatland carbon reservoirs accounting for the spatial/depth distribution of the gas. Broader Impacts This proposal incorporates educational activities, curriculum development, community outreach and international collaboration within an applied research framework. Honors UnderGraduate (HUG) researchers from the Rutgers-Newark Honors College (HC) will partner with a postdoctoral scientist to obtain the research training required to complete four of the primary research tasks. Each HUG will complete a yearlong senior project on their research and contribute to a publication. The status of Rutgers-Newark as the topranked National US University with respect to campus UG diversity facilitates HUG opportunities to minority students. Students in Earth/Environmental Sciences at Rutgers- Newark frequently express interest in fieldwork experiences. Part of the fieldwork will be conducted by students participating in a new class, Summer Field Camp in Applied Geophysics, developed as part of this project. Community outreach will occur via guided tours, poster boards and presentations on the hydrology, ecology and carbon cycle in Caribou Bog, facilitated by the recently opened 2 km long Orono boardwalk that now provides public access to this bog. Finally, collaboration with a prominent peatland scientist in Europe will draw international attention to our work and provide an opportunity to conduct comparative work on a unique European peat bog