Spatial Pattern of Dissolved Organic Carbon and its Specific Ultraviolet Absorbance under Different Scales in a Wetland Complex on the Eastern Tibetan Plateau

Abstract

The concentration of dissolved organic carbon (DOC) and the specific ultraviolet absorbance (SUVA) ofpeat, soil, and water samples collected from the Zoige wetlands on the eastern Tibetan Plateau in August2008 were determined. The DOC concentration was 36.34 ± 15.27 mg L-1, falling in the range of the DOCconcentration in wetlands of other regions. However, the mean SUVA of the DOC was 0.55 ± 0.33 Lmg-1m-1, showed a comparatively low aromaticity among wetlands. Significant variations of DOCconcentration and their SUVA were both found under different spatial scales. The results showed that boththe concentration and aromaticity of the DOC are influenced by the water table in the peatland. Thesignificant difference of the DOC concentration among the three types of wetland showed the influence ofplant growth on the DOC in the soils, and the SUVA indicated the different sources of the DOC in thedifferent wetlands. The results also indicated that the DOC concentrations in stream water are consistentto the proportion of peatlands in the corresponding catchment.