The effect of temperature and nitrogen deprivation on cell morphology and physiology of Symbiodinium

Nutrients and temperature are the major elements in maintaining stable endosymbiotic relationships. The mechanisms and response of cultured Symbiodinium cells in the absence of nitrogen, and at various temperatures are still unclear. The present study investigated the influence of different temperatures and nitrogen-deprivation on free-living Symbiodinium cultures. The physiological responses of free-living Symbiodinium cells cultured at different temperatures during nitrogen deprivation under a 12:12 h light:dark were measured. Symbiodinium cell growth was significantly lower in response to lower temperatures. Transmission electron micrographs (TEMs) revealed the formation of lipid droplets induced by nitrogen deprivation under different temperatures. The results of this study will increase our understanding of adaptive responses occurring in Symbiodinium under environmental stress.