THE QUANTIFICATION OF BIOGAS EMISSIONS FROM A GROUNDWATER-DEPENDENT ECOSYSTEM THROUGH NOVEL FIELD AND LABORATORY METHODS

Anthropogenic and natural greenhouse gases have increased our planets energy budget by trapping insolation and diminishing our atmosphere’s ability to reflect incoming light. The combination of these perpetuating mechanisms that deteriorate the habitability of our planet call for an understanding of their fundamental operation scientifically. Currently, there is a lack of quantification to the hydrogeologic sensitivities (groundwater level, soil textures, waters chemical condition, precipitation quantities, soil and air temperature) that contribute to the fluctuating emissions from wetlands. Focusing on nitrous oxide production rates within a groundwater-dependent ecosystem in Gunsan South Korea, novel methods have been applied to instruments such as soil kinetic cells and closed static gas chambers within a palustrine wetland to measure the emission rates of N₂O and N₂ gases from the field site. A total of 246 gas, 73 water, 42 soil, and 52 kinetic-cell samples were collected. During sample collection, field parameters of pH, conductivity, dissolved oxygen, redox potential, soil and air temperature, as well as groundwater levels were measured daily during a pre-monsoon, monsoon, and post-monsoon periods over a 4-week field survey conducted in summer, 2021. Preliminary results showed N₂O gas production rates vary with hydrologic and chemical conditions of the wetland and are positively correlated with precipitation. Novel field, laboratory, and modeling techniques developed by this study are applicable to other greenhouse gases and may pose a practical method for assessing soil contamination such as vapor intrusion by volatile organic carbon substances in the subsurface.