Methane sink of subterranean space in an integrated atmosphere-soil-cave system.

CH serves as an important greenhouse gas, yet limited knowledge is available in global and regional CH cycling, particularly in widely distributed karst terrain. In this study, we investigated an upland in Puding Karst Ecosystem Research Station, and explored CH concentration and/or flux in atmosphere, soil and cave using a closed static chamber method and an eddy covariance system. Meanwhile, we monitored atmospheric temperature, precipitation, temperature and wind velocity in the cave entrance.