[Mixing behavior of nutrients in different seasons at Liaohe Estuary]

The distribution and species of nutrients in the Daliaohe Estuary were studied in April, July and November, 2010. Concentrations of nutrients displayed obviously seasonal variability in the Daliaohe Estuary. Highest concentrations of PO4(3-) -P, DOP, DTP and TP were in April, and the lowest were in July. While the highest PP was in November, the lowest was in July. The contents of NO3(-) -N and NO2(-) -N reached the highest point in July, and the lowest was in April; however, the highest NH4(+) -N, DON and PN were in April and the lowest were in November. The main existing form of TN was NH4(+) -N in April, while in July and November NO3(-) -N was the dominant. The behavior of NO3(-) -N,DIN and TN was conservative in various seasons; the behavior of NO2(-) -N, NH4(+) -N and DON was conservative in April and November, while nonconservative in July, which indicated the exist of the extra source in the interior of the estuary. The SiO3(2-) of the Daliaohe Estuary was conservative, with the highest average concentration in November and the lowest in April.