Methane emissions from peat soils are highly variable both in space and time and are influenced by changes in certain biogeochemical controls (i.e. organic matter availability; redox potential) and/or other environmental factors (i.e. soil temperature; water level). Consequently, hot spots (areas with disproportionally high emissions) in wetlands may develop where biogeochemical and environmental conditions are especially conducive for enhancing certain microbial processes such as methanogenesis. Currently, the U.S. Geological Survey employs eddy covariance methods to quantify carbon and methane exchanges over several spatially extensive vegetation communities in the Big Cypress National Preserve (BCNP). While eddy covariance towers are a well-established tool for measuring gas exchange at the ecosystem scale, their extensive footprint (often hundreds of m2) may not provide enough spatial resolution to capture small-scale (i.e. sub meter) variability associated with the presence of hot spots for gas emissions, particularly when gas releases are characterized by rapid ebullition events. In this work, we investigate how different vegetation communities within the footprint of eddy covariance measurements at two different sites in BCNP contribute differently to the overall gas flux, and thus allowing for better characterizing spatial heterogeneities and presence of hot spots for methane gas release in peat soils. Our approach uses a unique combination of ground-penetrating radar, capacitance probes, gas traps, and time-lapse photography to compare to eddy covariance measurements, and demonstrates the importance of multi-scale measurements to properly characterize methane fluxes from subtropical peat soils and potentially assist with refining current terrestrial ecosystem models.
