Research On Phytoplankton Nutrient Structure In Jiaozhou Bay

When we can't determinate phytoplankton nutrient content and its composition in natural seawater now, measuring lab-cultured phytoplankton nutrient content and its composition can reflect characteristic of natural phytoplankton nutrient structure to some degree. C, N, P, Si content and composition of different sized phytoplankton dominant species were measured in this paper, then comparing with spot investigation seawater nutrient, different size chlorophyll.a concentration and historical studies, we explored the difference in different sea area, different size, different season phytoplankton nutrient content and its structure. The main conclusions are as follows:Horizontal distribution of layer nutrient concentration is similar to chlorophyll.a concentration in Jiaozhou Bay, which gradually decrease from northwest, eastwest bay to middle, south and out of the bay. Opposition to seasonal variation of chlorophyll.a concentration, nutrient concentration are higher in spring, autumn and lower in winter and summer.Except N content close, C,P,Si content of cultured Sk. Costatum from higher nutrients'Changjiang Estuary is higher than those of Jiaozhou Bay, especially in Si. C, N, P, Si contents in cell of different sized phytoplankton in Jiaozhou Bay increases along with the size increasing, which is the same to the proportion of C, N, and P content in cell, while the percent of Si are small differences among different sized phytoplankton. While the smaller size of Sk. Costatum is apt to absorb Si, the larger size of Ch. curvisetus and Th. nordenskioldi are inclined to absorb N and P. Similar to seawater nutrient concentration, C, N, P, Si content and the dry quality concentrations display the seasonal difference. C, N, P, Si content and the dry quality concentrations of cultured Sk. Costatum in winter are higher, while lower in spring. The ratios of lab-cultured phytoplankton N/P, C/N are closed to suspended particulates, when those of Si/P, Si/N are lower than suspended particulates. Similar to seawater and particulates nutrient structure in Jiaozhou Bay, high contents of C, N and relative low P, Si, high N/P ratios and low Si/P and Si/N ratios in lab-culture phytoplankton, showed that Si was possibly potential influence on phytoplankton growth.