Water Resources Research Act Program

Details for Project ID 2020MD179B

Developing an isotopic fingerprint for methane from Maryland wetlands

Institute: Maryland
Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $35,000 Total Non-Federal Funds: $70,000

Principal Investigators: James Farquhar

Abstract: The research proposed here focuses on developing an isotopologue fingerprint for methane from the Delmarva Bays freshwater wetlands. Isotopologues are the variants of molecules differing only in their isotopic composition. Given that two stable isotopes exist for carbon (12C and 13C) and also for Hydrogen (H and D), there there are 10 possible isotopologues for the 5 atom methane molecule. Using recently acquired state-of-the-art instrumentation at the University of Maryland, we plan to measure ratios for 5 of these isotopologues – 12CH4, 13CH4, 12CH3D, 13CH3D, 12CH2D2 – in samples of methane. Information provided by these measurements made for methane from incubation experiments and field sampling of Delmarva Bays freshwater wetlands will be used to trace chemical and physical processes, including mixing, and to provide a fingerprint to trace this source in future studies of the regional methane budget. The work with different temperature incubations will provide a controlled look at the methane isotopologue fingerprint and its dependence on temperature for the natural and the restored sites. Work with oxygen will provide a controlled look at the dependence on methane oxidation. Field sampling of the two sites for different seasons will provide ground truth for the incubations. Together, the findings will provide the first information for isotopologue fingerprints of methane from Maryland wetlands and also a starting point for larger study of wetlands and characterization of methane emissions from wetlands in our region. Our work will fingerprint the range of compositions of wetland methane for Delmarva Bay samples in controlled and natural conditions, allowing us to understand at a new level, the microbial processes and microbial community activity that respond seasonally to changes in environmental conditions. The isotopologue tracer is complementary to molecular biological techniques and provides information about biological and chemical transformation and proportions of methane produced and consumed. The research will support a postdoctoral investigator (PI Haghnegahdar) and an undergraduate intern (Nicole Hultquist). It will add synergies to parallel projects by a recently matriculated Ph.D. student (Rumya Ravi) and be incorporated into the broader education and outreach activities of the UMD Panorama Laboratory. The information we acquire is directly relevant to Federal and State missions related to geochemical processes occurring in wetlands and their connections to climate. It will also be the first step in a larger effort by the team of researchers affiliated with the UMD Panorama Laboratory to characterize the regional methane budget and the relationship between natural and human activities related to methane.