Temperature-ecological amplitude of Karenia mikimotoi and Prorocentrum donghaiense at different light intensities in laboratory culture

Karenia mikimotoi and Prorocentrum donghaiense are the major dominant species in red tides in southeast coastal area of China.To determine the temperature-ecological amplitude of Karenia mikimotoi and Prorocentrum donghaiense,firstly,experiments at four level temperatures（18,22,25,and 28℃）on cell densities and specific growth rates of Karenia mikimotoi and Prorocentrum donghaiense at three light intensities(28.32,75.06,and 111.66μmol m-2s-1)were conducted,and then,a tolerance model between temperature and specific growth rate of the algae was established based on experimental results and Shelford’s law of tolerance;finally,the optimum temperature for algal growth,suitable temperature ranges for algal growth,and tolerance temperature ranges for algal growth were determined respectively according to our existing research results.The results showed the following:（1）Whether Karenia mikimotoi or Prorocentrum donghaiense,there existed an optimum temperature for algal growth(Topt)in the given temperature gradient level under the same light conditions,and when T≤Topt,the cell densities and specific growth rates of Karenia mikimotoi and Prorocentrum donghaiense increased significantly with increase in temperature（ANOVA,P