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

The concentration of dissolved organic carbon (DOG) and the specific ultraviolet absorbance (SUVA) of peat, soil, and water samples collected from the Zoige wetlands on the eastern Tibetan Plateau in August 2008 were determined. The DOC concentration was 36.34 +/- 15.27 mg L-1, falling in the range of the DOC concentration in wetlands of other regions. However, the mean SUVA of the DOC was 0.55 +/- 0.33 L mg(-1) m(-1), showed a comparatively low aromaticity among wetlands. Significant variations of DOC concentration and their SUVA were both found under different spatial scales. The results showed that both the concentration and aromaticity of the DOC are influenced by the water table in the peatland. The significant difference of the DOC concentration among the three types of wetland showed the influence of plant growth on the DOC in the soils, and the SUVA indicated the different sources of the DOC in the different wetlands. The results also indicated that the DOC concentrations in stream water are consistent to the proportion of peatlands in the corresponding catchment.