| Abstrakt: |
To better understand the role of the dissolved organic carbon (DOC) transported by hydrological processes in soil respiration in tropical rainforests, we measured: (1) the DOC flux in rainfall, throughfall, litter leachate, and surface soil water (0-20 cm), (2) the seasonality of δ13CDOC in each hydrological process, and δ13C in leaves, litter, and surface soil, and (3) soil respiration in a tropical rainforest in Xishuangbanna, southwest China. The results showed: the surface soil intercepted 94.4 ± 1.2 % of the annual litter leachate DOC flux and is a sink for DOC. The throughfall and litter leachate DOC fluxes amounted to 6.81 % and 7.23 % of the net ecosystem exchange, respectively, indicating that the DOC flux through hydrological processes is a key component of the carbon budget, and may be a key link between hydrological processes and soil respiration in the tropical rainforest. The difference in δ13C among the soil, soil water (at 0-20 cm), throughfall, and litter leachate indicated that DOC is transformed in the surface soil. The variability in soil respiration is more dependent on the hydrologically transported DOC flux than on the soil water content (at 0-20 cm), and is more sensitive to the soil water DOC flux (at 0-20 cm) than to the soil temperature, which suggests that soil respiration is more sensitive to the DOC flux in hydrological processes, especially the soil water DOC flux, than to soil temperature or soil moisture. [ABSTRACT FROM AUTHOR] |
