The Relationships of the Nutrients in the Changjiang River Estuary and the Flow of the Changjiang River Water

Abstract

In the Changjiang estuary, the high concentration area of phosphate (PO₄–P), SiO₃–Si and NO₃–N gradually reduced with the reduction of the area of the Changjiang diluted water from summer, autumn to winter. The seasonal distributions of the nutrients were mainly controlled by the river flow and were also related to the growth and decline of phytoplankton . The conservation of SiO₃–Si and NO₃–N in the estuary in the flood season was poorer than that in the dry season . The behaviour of PO₄–P shows that in addition to biological removal , the buffering of PO₄–P is possible in the estuary. The Changjiang’s annual nutrient transports to the sea were estimated. The investigation shows that the seasonal variations of the nutrient transport closely correlate with that of the flow of the Changjiang River and is confirmed by the investigations in 1997–1998 (Shen et al. in Ambio 32:65–69, 2003; Shen in Acta Geogr Sinica 61:741–751, 2006) and 2004 (Shen et al. in Environ Monitor Assess 184:6491–6505, 2012).