Effects of temperature and salinity on growth of Gyrodinium instriatum

The effects of temperature and salinity on the growth of the red tide dinoflagellate Gyrodinium instriatum were examined under the laboratory conditions.Exposed in 28 different combinations of temperature(15～30 ℃) and salinity(0～35),G.instriatum was exhibited the maximum growth at a combination of 20 ℃ and a salinity of 25.The optimum growth was observed at temperatures ranging from 20 to 25 ℃ and at salinities from 20 to 25.The resistance to low and high temperatures was increased under optimum salinity and vice versa.The organism could not grow at the salinity of 0 at all temperatures,but grew at the salinity of 10 at temperatures between 20 and 25 ℃.It is noteworthy that G.instriatum is an euryhaline organism and can live under low salinity.It might be the important reason why its blooms generally occurred in the estuaries with low salinity.