Carbon Fluxes and Potential Soil Accumulation within Greater Everglades Cypress and Pine Forested Wetlands

Methane Gas Ebullition Dynamics From Different Subtropical Wetland Vegetation Communities in Big Cypress National Preserve, Florida Are Revealed Using a Multi‐Method, Multi‐Scale Approach

“…The eddy covariance method was used to compute CH 4 fluxes during this study and additional details for all the processing, filtering, and gap‐filling procedures used to create this data set are fully described in Shoemaker et al. (2021). For brevity, we highlight several important considerations here.…”

“…For brevity, we highlight several important considerations here. CH 4 fluxes were measured using an LI‐7700 open‐path CH 4 analyzer (LI‐COR, Nebraska, USA) and were only conducted at the Site 2 due to (a) CH 4 analyzer cost, (b) safety issues associated with servicing instruments on tall towers, and (c) evidence that methane emissions from Site 1 were small (Shoemaker et al., 2021). Other key instrumentation installed at the Site 2 tower included sensors to measure soil temperature, air temperature, and water level.…”

“…Roughly 17% of values were removed by the unrealistic value, local despike, and u* filters at Site 2. An artificial neural network (ANN) technique was used to gap-fill missing fluxes and estimate random error uncertainty (Anderson et al, 2016) and is fully described in Shoemaker et al (2021). Data were processed using EddyPro software by LI-COR.…”

“…The Raw 10-Hz data were processed into mean half-hourly CH 4 fluxes following protocols which included uncertainty estimates, spiking filters, double coordinate rotations, blocked-average detrending, statistical filters, air density and oxygen corrections, and high-pass filtering (Baldocchi et al, 1988;Finkelstein & Sims, 2001;Tanner & Thurtell, 1969;Tanner et al, 1993;Webb et al, 1980). The mean half-hourly CH 4 fluxes were filtered to remove unrealistic fluxes which were defined as greater than 0.5 and less than −0.2 g C m −2 d −1 (Shoemaker et al, 2021). A local de-spike filter removed half-hourly CH 4 fluxes that were outside three standard deviations within a moving 7-day window, and a friction velocity (u*) threshold of 0.1 m s −1 was used for the Site 2 station (Shoemaker et al, 2015(Shoemaker et al, , 2021.…”

“…The mean half-hourly CH 4 fluxes were filtered to remove unrealistic fluxes which were defined as greater than 0.5 and less than −0.2 g C m −2 d −1 (Shoemaker et al, 2021). A local de-spike filter removed half-hourly CH 4 fluxes that were outside three standard deviations within a moving 7-day window, and a friction velocity (u*) threshold of 0.1 m s −1 was used for the Site 2 station (Shoemaker et al, 2015(Shoemaker et al, , 2021. Roughly 17% of values were removed by the unrealistic value, local despike, and u* filters at Site 2.…”