THE HYDROLOGY AND CARBON CYCLE OF FRESHWATER FORESTED WETLANDS, SOUTH EASTERN U.S.A

The environmental variables: soil temperature, water level position and soil redox were measured in conjunction with gross and microbial soil respiration rates and methane emissions along a freshwater tidal gradient in a bottomland forest from May 2015 through January 2016. Soil respiration and methane emission rates were measured with standard static chamber techniques, with chambers situated on sites representative of the hummock and hollow microtopograhy characteristic of these low gradient tidal wetlands. Wetland microtopography was found to significantly influence soil and microbial respiration rates but significant differences in these rates were not measured between similar topographic sites along the tidal gradient. Methane emissions were measured at two locations along the tidal gradient with tidally impacted hollows exhibiting significantly higher emission rates during the growing season than all other sites measured during the study. Elevated CH₄ emissions in tidal hollows are hypothesized to be related to seasonal increases in soil temperature and ebullition during inter tidal periods.