Dissolved organic carbon (DOC) is the most dynamic component in the carbon pool of terrestrial forest landscapes. The continuous flow of DOC within and outside forest ecosystems is a key pathway for carbon movement, and transport of biogenic elements, heavy metals and organic pollutants. Thus, DOC is an essential part of carbon budget of forest ecosystems. Most studies have examined the composition, dynamic and controlling factors for dissolved organic matter at forest, but little is known about the transport and transform of DOC when it passes through soil. 

Under the supervise of Professor LIU Feng, WANG Min, a Ph.D student from Wuhan Botanical Garden, added ¹³C-labelled litter-derived DOC into different depth soil columns in a 180 °C incubation experiment and quantified the fate of ¹³C-labelled litter-derived DOC in soil (including retention, mineralization and leaching).  

Results showed that soil retention of DOC was likely the dominant mechanism, with minor microbial degradation and minimal leaching. Parallel factor analysis indicated that the component composition of water soluble organic carbon (WSOC) and the leached dissolved organic carbon (LDOC) were mostly comparable between the control and treatment. This indicated that the quality of WSOC and LDOC was more similar to soil carbon rather than the added DOC, which supported the dynamic exchange model. 

The present study was supported by the National Natural Sciences Foundation of China. Related research results entitled "The fate of litter-derived dissolved organic carbon in forest soils: results from an incubation experiment" were published on Biogeochemistry. 

The fate of litter-derived DOC at different soil depths (Image by WBG)