Burping wetlands : quantifying greenhouse gas ebullition rates across a range of sediment types and characteristics, water quality variables, and land use

Abstract

Aquatic ecosystems are a source of greenhouse gases (GHG) to the atmosphere. One pathway of this GHG release is ebullition, or bubbling, from aquatic sediments. The contribution of ebullition is often underestimated in global GHG budgets, as it is rarely included in GHG emission measurements. The ebullition pathway can account for up to 67 percent of methane emissions from water bodies. We aim to determine the factors that influence ebullition of methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O), including sediment characteristics, water quality characteristics, and land use. Our study ponds are in urban, agricultural, and woodland areas. We found that N2O flux rates are significantly lower than CH4 and CO2 flux rates across all study ponds. We also found that urban areas have higher GHG flux rates, which is correlated with low organic matter content. Understanding the factors influencing GHG ebullition from aquatic ecosystems will give us a broader understanding of the significance of their contribution to global GHG budgets in a changing climate.