[Examination of silicate limitation of primary production by diatoms phytoplankton in the Daihai Lake].

ABSTRACT

The Daihai Lake (40 degrees 29'27"-40 degrees 37'6"N, 112 degrees 33'31"-112 degrees 46'40"E) is a typical inland lake in a semiarid region in Inner Mongolia, China. Based on the geochemistry character of biogenic silica (BSi) in the water-sediments system of the Daihai Lake, the theory of silicate limitation of Primary Production by Diatoms phytoplankton in the Daihai Lake are discussed in this work by interpreting the information of the BSi concentrations, horizontal and vertical distributions and the response relation between BSi and past environmental conditions. It is found that the concentration of Si is very low in overlying water while very high in the sediments. The spatial distribution patters of SiO3(2-) and BSi suggest the Si source of the lake. The geochemistry information of BSi is well archived in the lake sediment profiles, and the geochemistry information of BSi well responses to the past environmental conditions of the Daihai drainage basin. The ratios between Si, and C, N, P in the water-sediment system and the response relation between BSi and past environmental conditions indicate the main reasons for the theory of silicate limitation of Primary Production by Diatoms phytoplankton. Furthermore, the dominant factor for silicate limitation of Primary Production by Diatoms phytoplankton is different in different periods.