Difference of water and nutrients budgets in estuary of the Yellow River between 80´s and 90´s

Difference of Dissolved Inorganic Nitrogen (DIN) and Dissolved Inorganic Phosphorus (DIP) budgets in the Bohai Sea between 1980s and 1990s related the decrease of the Yellow River discharge is discussed on the basis of observed data. The estuarine circulation in the Bohai Sea had been weakened from 80s to 90s due to the decrease of the Yellow River discharge and the average residence time of fresh water had become longer. DIN concentration increased but DIP concentrations decreased from 80s to 90s in the Bohai Sea. Primary production was regulated mainly by water temperature and DIN concentration in 80s but it was regulated mainly by DIP concentration in 90s. Primary production was larger than decomposition plus bottom release and nitrogen fixation was larger than denitrification in 90s. However, decomposition plus bottom release was larger than primary production and denitrification was larger than nitrogen fixation in 90s in the Bohai Sea.