A study on dissolved organic carbon and nitrogen nutrients under Chinese fir plantation: Relationships with soil nutrients Effects of water gradient on soil enzyme activity and active organic carbon composition under Carex lasiocarpa marsh Attenuation of solar ultraviolet radiation and analysis of attenuators in typical macrophytic, algal lake zones of Lake Taihu Transport characteristics of dissolved organic carbon in different soil horizons in natural Castanopsis carlesii forest Active soil organic matter and its relationship with soil quality Origin, property and flux of dissolved organic matter in forest ecosystems Effects of nitrogen deposition on critical fractions of soil organic carbon in terrestrial ecosystems