Distribution of chlorophyll-a and primary productivity in Yantai Sishili Bay

In May, August and October 2006～2010, thirty integrated surveys of coastal water environment were carried out in Yantai Sishili Bay (YSB) twice per month. Mornitored items included water quality, phytoplankton, surface chlorophyll-a and hydrometeorology. The spacial and temporal distribution of chlorophyll-a and primary productivity in YSB was studied. The results showed that phytoplankton density, chlorophyll-a concentration and primary productivity were generally higher in August; But in 2008,the maximum of phytoplankton density appeared in October, and in 2009 the maximums of both chlorophyll-a concentration and primary productivity appeared in May. In October 2008, the phytoplankton density, the highest during the survey period, reached 51.61×104 cells/L, and significant differences were found among all six sampling sites(P0.01); The lowest value (0.02×104 cells/L) appeared in October 2007. From 2006 to 2009 both chlorophyll-a concentration and primary productivity showed a growing trend, but in 2010 they decreased to a similar level as 2008. In the last five years,phytoplankton density, chlorophyll-a concentration and primary productivity were generally higher in east YSB than in the west. Furthermore, a significant positive correlation was found between primary productivity and chlorophyll-a concentration (R=0.921,P0.01), and a regression equation was developed. It will offer an option to estimate and assess the primary productivity of the coastal waters.