Abstract
To examine the effect of salinity on the voluminal changes of Chlorella and rotifer, their PV (packed volume) were measured at various salinity (0, 10, 20, 30, 40, 50, 60 and 70 psu) . Chlorella regularis and marine rotifer Brachionus rotundiformis acclimated to the seawater of either 20 or 30 psu for 3 days were used for this experiment. When Chlorella was soaked in the artificial seawater of higher salinity, the PV of Chlorella decreased and stabilized after 4h. When the rotifers were soaked in various salinities of the artificial seawater, their PV increased at lower salinities and decreased at higher salinities. The bigger the difference between soaked salinity and acclimated salinity was, the greater stress the rotifers had and eventually stopped swimming. Although both the PVs and swimming ratio of rotifers recovered almost to original volumes 8 h after the salinities were back to 10-30 psu, the ability of the osmoregulation of rotifers acclimated to 30 psu might be stronger than that rotifer acclimated to 20 psu.
