![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
Most shallow-water coelenterates, such as the hard corals, soft corals, and gorgonians, contain symbiotic algae, zooxanthellae, which are the nonmotile “vegetative” forms of dinoflagellates included in the genus Symbiodinium. The zooxanthellae play an important part in the nutrition and calcification of their hosts. They may also contribute defensive chemicals which assist the host in surviving predation and the intensive competition for space on coral reefs. The zooxanthellae contribute considerable organic matter to the sediments, some of which may serve as thalasso-biogeochemical markers. A wide variety of sterols are found in zooxanthellae. Some have been used as tracers to identify predators on coelenterates. The sterol patterns of zooxanthellae isolated from various hosts vary and indicate the occurrence of many different species of the genus Symbiodinium. The chemistry of the algal symbiont in the host differs from that of the motile form grown in axenic culture.