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Variations of dissolved silicate (DSi) flux in the Yangtze River have caused great concern among scientists. Analysis of spatial and temporal variations of DSi indicates that the distribution of DSi concentration (DSiC) is closely related to the occurrence of bedrocks in the river cathchment. On average, the upper Yangtze River and Dongting and Poyang Lake of the middle Yangtze basin serve as the major DSi sinks, retaining 3.39×10⁴t y⁻¹, 5.59×10⁴ and 2.51×10⁴t y⁻¹. The middle and low Yangtze River remains DSi sources, emitting 2.85×10⁴ and 2.48×10⁴t y⁻¹, respectively. Geochemical data at Datong hydrological station recorded the flux of nutrients entering into the sea during the flood season, i.e. 74% for DSi, 73% for DIN (Dissolved Inorganic Nitrate) and 68% DIP (Dissolved Inorganic Phosphate). The yearly DSiC and flux show a sharp decrease since 1950s. The mean DSiC was 109.47, 91.09, and 77 …