Measuring Methane Emission from Fish Ponds with Micrometeorological and Water Equilibrium Methods

Shallow fish ponds comprise over 40% of freshwater ponds in China. They contain large amounts of organic matter, including organic feed material, aquatic grass and waste produced aquatic animals, and may generate large CH4 emissions to the atmosphere. In the study, we measured the CH4 emission in fish ponds in Anhui Province in eastern China using the flux-gradient method, the eddy covariance method and the water-equilibrium method. The two objectives of the study were to (1) quantify the CH4 emission from these ponds, and (2) to identify critical environmental factors that regulate the emission intensity. The preliminary results indicated that the CH4 emission flux was on the order of 0.9 μg m-2 s-1 in the summer, which is much higher than the median value reported for inland lakes (0.05 μg m-2 s-1).