Seasonal dynamics of chromophoric dissolved organic matter in Poyang Lake, the largest freshwater lake in China

•CDOM showed more terrigenous characteristics with higher aromaticity and lower DOC in the rising and flood season than in the dry and retreating season.•CDOM from the five main input rivers to the lake can exceed 50% in the rising season.•Flooding causes wetlands to contribute a higher abundance of CDOM and DOC with lower aromaticity to the lake.•Support vector regression can predict DOC concentration by estimating the seasonal and spatial variation of CDOM in a large lake.