Identification Of Sarcophyton Sp.and Effects Of High Temperature Stress On Symbiotic Biodiversity In Two Corals

(1)Alcyoniidae is an important part of the coral Reef Ecosystem and has strong medicinal value.Alcyoniidae resources are very rich in our country,but,the research on the classification of soft corals is stagnant at present.In the environment of global warming,Coral Reef resources are declining,and the research on the diversity of soft corals is urgently needed.Identification of 26 samples of Sarcophyton spp.which collected from West Island in Sanya City,Ganzhe Island and Dazhou Island Reef Area in Wanning City,Hainan Province,according to the preliminary identification of morphology,and through the analysis of the mshl gene and COI gene sequence of Octocorallia mitochondria.The results showed that Integrating morphological and molecular,this study identified all the collected samples of Sarcophyton as 5 species,which were Sarcophyton cherbonnieri Tixier-Durivault 1958、Sarcophyton crissum Tixier-Durivault 1946、Sarcophyton trocheliophorum Marenzller 1886、Sarcophyton glaucum Quoy&Gaimard 1833 and Sarcophyton ehrenbergi von Marenzller 1886.Sarcophyton cherbonnieri Tixier-Durivault 1958 and Sarcophyton crissum Tixier-Durivault 1946 are new record species in China.This study provided a reference for the identification of Sarcophyton sp.in the Hainan Island,and provided data support for the research on the species identification of Soft Corals in China.(2)Global warming is threatening corals and Coral Reef ecosystems.Zooxanthellae and Bacteria are very important components of coral symbioses.They play a very important role in corals responding to temperature stress.Studying the ability of coral symbioses to cope with changes in the environment is very important for the regeneration and recovery of corals.In this study,High-throughput sequencing technology was used to detect the changes of symbiotic Bacteria and Symbiodinium of Sarcophyton trocheliophorum and Euphyllia ancora after temperature stress.The results show:1)After temperature stress,the abundance of symbiotic bacteria in both Sarcophyton trocheliophorum and Euphyllia ancora decreased.The diversity of the symbiotic Bacteria of Sarcophyton trocheliophorum,and the dominant species became the genus of Delftia and Serratia which related to coral diseases.The diversity of Euphyllia ancora increases,and bacteria in surrounding seawater(such as Alphaproteobacteria)enter the coral symbiotic system.2)Before temperature stress,the symbiotic Symbiodinium of Sarcophyton trocheliophorum consists of C1,C161,C18,C72 and C1C.C45,and the dominant species is C1 with an abundance ratio of about 97%.Euphyllia ancora symbiotic Symbiodinium mainly consists of D17,D5,D2,D3,and D1a.The dominant species is D17 with an abundance of about 60%.After temperature stress,the symbiotic Symbiodinium ofSarcophyton trocheliophorum increased C3,while other components remained unchanged,and C1 remained the dominant species.The composition of the symbiotic Symbiodinium of the Euphyllia ancora is unchanged,the abundance of D5 is decreased,and the abundance of D1a is increased.D17 is still the dominant species.