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Based on the results of water sample measurements of nutrient concentrations at th e Datong Station of the Changjiang River from 1998 to 1999, combined w ith historical data of water quality, seasonal variations of nutrient concentrations and nutrient transports are discussed.The following results have been obtained: (1) the fluxes of the nitrate nitrogen, ammonium nitrogen and nitrite nitrogen increased by time-series from 1962 to 1990 , even if runoff volume had a little variation; (2) the concentrations and fluxes of the dissolved inorganic nitrogen (DIN) and dissolved in organic phosphorus (DIP) increased notably with time, but those of the dissolved silicon (DSI) decreased pronouncedly; and (3) the concentration s and fluxes changed synchronously with time between the Datong Station a nd the Changjiang Estuary.
Based on the results of water sample measurements of nutrient concentrations at th Datong Station of the Changjiang River from 1998 to 1999, combined w ith historical data of water quality, seasonal variations of nutrient concentrations and nutrient transports are discussed. Following results have been (2) the fluxes of the nitrate nitrogen, ammonium nitrogen and nitrite nitrogen increased by time-series from 1962 to 1990, even if runoff volume had a little variation; (2) the concentrations and fluxes of the dissolved inorganic nitrogen ) and dissolved in organic phosphorus (DIP) increased not with time, but those of the dissolved silicon (DSI) decreased pronounced; and (3) the concentration s and fluxes changed synchronously with time between the Datong Station a nd the Changjiang Estuary.