Excessive input of anthropogenic reactive nitrogen (Nr) to forested ecosystems is associated with increased rates of denitrification and possible emission of the potentially harmful greenhouse gas nitrous oxide (N 2 O).Denitrification is performed by heterotrophic bacteria, and Dissolved Organic Matter (DOM) is thus required for the process to proceed. Only a fraction of DOM is however assumed to be readily available for the bacteria. In a N- saturated subtropical forest in South China (Tie Shan Ping) potential denitrification rates and growthpotential have been investigated in the framework of a study on N2 O emissions. Spatial variations were found, displaying higher denitrification rates at the unsaturated hill slope (recharge zone) as compared to the more hydromorphic groundwater discharge zone. Thesefindings were explained by the denitrifiers being C - limited, which was especially evident at the groundwater discharge zone. Itwas hypothesized that the reduced transport of DOM from the densely vegetated hill slope to the groundwater discharge zone was attributed to rapid mineralization along the flow path. This would result in only the more recalcitrant fraction ofDOM remaining in solution for transportation to the groundwater discharge zone. The objective of this present study was to test this hypothesis by investigating differences in chemical characteristics and biodegradability of the DOM between the hill slope and thegroundwater discharge zone. Soil-water samples collected along a topographic gradient, using suction lysimeters, were subject to both biological-, chemical-, and structural analyses. Measured biodegradability, using a batch experimental setup, suggested thatthe DOM from the groundwater discharge zone was far more biodegradable than the DOM from the hill slope. This was further corroborated with the structural characterization, using UV- Vis Absorbency and Fluorescence Spectroscopy, indicating small amount of more aromatic, and alow ratio of Humic to Fulvic acids in the DOM from the groundwater discharge zone as compared to the samples from the hill slope. This would imply that the attenuation of DOM along the flow path in Tie Shan Ping could not be attributedto mineralization. Instead, the loss of less biodegradable DOM is suggested to be explained by selective adsorption of themore aromatic, higher molecular weight, hydrophobic constituents of DOM to the clay-rich and organic-poor soils of the hill slope.