Salt-wedge intrusion and its influence on environmental factors in the Modaomen Channel, Pearl River Estuary
珠江口磨刀门咸潮及其对环境要素变化的影响

In order to investigate the effects of seawater intrusion on environmental factors, an anchor station survey was conducted during the neap tide from January 25 to 26, 2011. During the survey, the dissolved oxygen, PO3-4 and heavy metals (Zn, Cd) had no significant tidal variations. The concentration of NO-2, NH+4 decreased during the survey, while SiO-4, NO-3 in bottom water had concurrent variations with tidal circulation. When the shear stress was higher than 0.226 N·m2, there was significant sediment resuspension from the river bed. The atomic ratios of N, P, Si indicated that the phytoplankton growth was potentially limited by P, however, this condition might be changed by increasing seawater intrusion intensity. The N, P pollutions were still far from being safe for environment, the seawater intrusion was not helpful for pollutants elimination in Modaomen Channel, there was consistently a risk of secondary pollution under the role of tidal circulation.