Abstract:Population growth rate, nutrient consumption, and the chlorophyll a and polysaccharide content of the coccolithophore Pleurochrysis sp. —— isolated from a bloom in a shrimp pond near Xiangshan Bay China——were studied as a function of temperature, irradiance, and salinity. The environmental parameters include two temperatures (low, 7℃; high, 25℃), two irradiance levels (low, <2 μE•m-2s-1；high, 100 μE•m-2s-1), and four salinities (5, 15, 30, 45). At low temperature-low irradiance, Pleurochrysis sp. survived but did not grow, and at high temperature-low irradiance the cells died. However, Pleurochrysis sp. grew well under high irradiance at both high and low temperatures. Growth curves show that Pleurochrysis sp. has different growth patterns at high and low temperature. At low temperature, the cells experience a lag phase of very slow growth, low nitrogen and phosphorus consumption, and a decrease in Chl-a content, followed by a rapid grow phase with a large consumption of nitrogen and phosphorus, a gradual increase of Chl-a, a higher polysaccharide content than that at high temperature, but no further polysaccharide accumulation. At high temperature, Pleurochrysis sp. grows very fast from the outset with rapid consumption of nitrogen and phosphorus, a slight increase in Chl-a content. Polysaccharides accumulate later during the subsequent stationary growth phase. Pleurochrysis sp. growth pattern was similar in 45, 30, and 15, except at 5.