Distribution and annual variation of chlorophyll a in summer in the sea area of the Yangshan Deepwater Port

Based on the data taken from the surveyings conducted in the sea area around Yangshan Deepwater Port project in August from 2001 to 2006(except 2002),the variations of chlorophyll a have been analyzed.The average concentrations decreased significantly in the first three years,but increased slightly in the following two years.The maximum concentration was 2.61 mg/m3 in 2001,while the minimum was only 1.27 mg/m3 in 2004.The variations of chlorophyll a in the area of dockland and seaway were consistant with that of the whole area,but it slightly differed in the East China Sea Bridge area,which decreased gradually in the first four years and increased from 2006.The benthic concentration reduced faster but increased slower than the concentation of the surface.And the former was higher than the latter in 2001,while it was just opposite to that from 2003 to 2006.Moreover,the annual variation of chlorophyll a went along with the abundance of phytoplankton,but there was no obvious correlation between them.