Methane emissions from wetlands are an important component of the global carbon budget. Changes in temperature and hydrology (e.g., water depth, hydroperiod, soil saturation) that are expected from climate change will affect belowground processes such as methanogenesis and methanotrophy, which will impact methane fluxes from wetlands. The prairie pothole region (PPR) in central North America covers 800,000 km2 and consists of millions of depressional wetlands that each have significant potential to emit methane. Six years of bi-weekly methane flux measurements were conducted during the snow-free period in six temporarily and seasonally ponded (‘temporary group’) and six semipermanently and permanently ponded (‘permanent group’) wetlands located at a prairie grassland site in North Dakota, USA.
Results/Conclusions
Methane flux rates increased with increasing temperature and water depth, and were especially high when conditions were warmer and wetter than average. Methane flux rates from permanent wetlands were less sensitive to changes in water depth and temperature compared to temporary wetlands, which was likely due to higher sulfate concentrations in permanents inhibiting methane production. While the predicted increase in temperature with climate change will likely increase methane emission from PPR wetlands, differences in hydrology and chemistry among these wetlands could moderate (or compound) these increases.