Response of Arctic marine microalgae to changes of salinity

An algal assemblage collected from the bottom of floe in the Greenland Sea was batchcultured at 1±1℃ and 10 salinity gradients varied from 4 0 to 90 8 for 19 d.The growth for both the algal community and individual populations was characterized by an initial lag phase of six days followed by positive growth.Maximum growth rates were obtained as 0 19/d for the algal community and 0 32 to 0 39 d -1 for individual populations for the whole experiment period,which mostly occurred at the lower salinities.The competition between the algal species and the evolution of the algal assemblages under the salinity changes was checked.After 14 d culture,the dominating algae in the lower salinities were centric diatoms,pennate diatoms and phytoflagellates,while ones in the higher salinities almost belonged to pennate diatoms.It is suggested that the sea ice algal community from the Greenland Sea prefer lower salinities to higher ones,and the decrease in salinity in small ranges could stimulate the growth of sea ice algae.