Batch cultures of P. donghaiense were maintained in 0.22 filtered and autoclaved seawater (30 psu) with K medium, and grown under cool white fluorescent light at an irradiance of 100 μmol quanta m-2 s-1 with a 14:10 h light: dark cycle at 25 ℃. Tripicated experiments at 19, 22, 25 and 28 ℃ were performed in 2 L acid-washed and autoclaved polycarbonate bottles containing 1.6 L medium. To obtain stable metabolic activity of cells, P. donghaiense at each temperature were cultured and semi-continuously diluted daily for approximately 20 days before samplings.