Abstract: Based on the survey data of particulate organic carbon (POC) and dissolved organic carbon (DOC) concentration in Tangxi River from July 2014 to June 2015, its spatial and temporal distribution characteristics were studied, and the source of POC was analyzed combined with correlation of POC, DOC, TOC, POC and C/N. The results showed that DOC annual average mass concentration in Tangxi River water range was between 2.53-3.91 mg/L, DOC accounted for more than 60% of total organic carbon, POC mass concentration ranged from 1.62 to 2.53 mg/L. In the spatial distribution, the DOC concentration annual average value increased gradually from 1# to 5# sampling site, the POC concentration average value changed slightly at each sampling site. In the temporal distribution, DOC and POC concentrations were higher in summer than that in spring and autumn, and the lowest in winter. Result showed that the concentrations of DOC and POC changed in each season.

Key words: POC, DOC, seasonal variation, source, C/N, Tangxi River