Discharge pattern of symbiotic zooxanthellae from corals

珊瑚有虫黄藻（共生鞭毛属）作为共生体。从珊瑚排出虫黄藻与珊瑚白化密切相关。虽然放电可以在非应力条件下发生，但对放电的时间或放电的电池数量知之甚少。我们进行了实地和实验室实验，以澄清珊瑚排出虫黄藻的模式。结果表明：(1)不同珊瑚群落排出的细胞数量不同；(2)白天珊瑚释放的虫黄藻比夜间多；(3)水温越高，电池的排水量越大；(4)高温也抑制了珊瑚组织内虫黄藻的细胞分裂。因此，在高温条件下，珊瑚的白化现象似乎与珊瑚排出的细胞数量增加和珊瑚内部的细胞分裂减少有关。

Corals harbor zooxanthellae (dinoflagellate genus Symbiodinium) as symbionts. Discharge of zooxanthellae from corals is closely linked to coral bleaching. Although discharge can take place under non-stress conditions, little is known about the timing of discharge or the quantity of cells discharged. We performed field and laboratory experiments to clarify the pattern of zooxanthellae discharge from corals. The results revealed that (1) the number of cells discharged varied among coral colonies; (2) the corals tended to release more zooxanthellae during the daytime than during the night; (3) more cells were discharged when the water temperature was high; and (4) high water temperatures also inhibited cell division of zooxanthellae within coral tissues. Thus, it is plausible that an increased number of cells discharged from corals and fewer cell divisions within corals are involved in coral bleaching under high water temperature conditions.