Date of Award

Fall 2010

Project Type


Program or Major

Earth Science: Geochemical Systems

Degree Name

Master of Science

First Advisor

Ruth Varner


Despite leading to a potentially significant positive climate feedback, the processes controlling wetland methane fluxes remain relatively poorly understood. Automated chambers were employed in a temperate peatland site to quantify the timing and magnitude of methane ebullition (bubbling), one of the three pathways for wetland methane flux. The resulting datasets offer high temporal coverage of both components of this flux pathway, allowing for the first analysis of ebullition variability on seasonal, synoptic and diel timescales. The seasonal peak in ebullition occurred in August, likely due to high methane production rates and low methane solubility, both driven by temperature. Synoptic scale variability was driven by hydrostatic pressure variations due to water table position. A daily pattern in ebullition was identified, with peaks at night. Several potential mechanisms for this pattern were explored. The cumulative contribution of ebullition to total methane flux during the summer was estimated to be 2--12%.