[Phenomena of pH instant increasing and its effect on dissolved inorganic carbon flux to sea in Yellow River estuary].

Dissolved inorganic carbon (DIC), pH, the partial pressure of CO (pCO2), total alkalinity (TA), dissolved oxygen saturation (DO), chlorophyll a (Chl-a), and NH4+, PO4(3-) were studied in mixing zone of Yellow River estuary from September 2004 to April 2006. The results indicate that pH value is higher than that of freshwater in low salinity area where DIC is non-conservative. NH4+, PO4(3-) sharply decreasing indicates that biogenic respiration is possibly inhibited in early mixing of freshwater and seawater, then pCO2, which is derived from biogenic respiration, swiftly decrease and lead to CaCO3 precipitation in low salinity area, and the pH value will simultaneously increase in this area.