Seasonal Variation Features of Nutrients and Influenced Environmental Factors in Weihai Bay
威海湾营养盐季节变化特征及与环境因子的相关性分析

The variation features of nutrients include inorganic nitrogen(DIN),phosphate(PO34--P),and silicate(SiO23--Si) in Weihai Bay were analyzed based on the four investigations during 2006-2007.The results showed that the main form of DIN was NO3--N with the percentage above of 50%.The seasonal variation of nutrients was significant.The concentrations of DIN and PO43--P was higher in autumn and winter than that in spring and summer.However,the seasonal variation of SiO23--Si was contrary to DIN and PO34--P.The concentrations of nutrients in all the seasons were higher than the growth threshold of phytoplankton,except SiO23--Si concentration was lower than the growth threshold of phytoplankton in winter.Si was the limiting factor for the growth of phytoplankton in winter,and P was the potential limiting factor in other seasons.There was a great canonical relationship between nutrients and environmental factors with the maximum coefficient of 0.979 between salinity,pH and NO3--N,PO34--P,SiO23--Si.