| Summary: | 碩士 === 國立臺灣大學 === 海洋研究所 === 99 === Association with thermally tolerant zooxanthellae (Symbiodinium) is one of the mechanisms for reef-building corals to survive the rising seawater temperature under the impact of future climate change. Previous studies have indicated that certain coral species can withstand extreme temperature fluctuations at unusual habitats (such as tidal pools, intertidal regions, etc) by hosting thermally tolerant clade of Symbiodinium sp. (D1a; S. trenchi). In this study, Platygyra verweyi were sampled from 1-3 m depth at 10 sites in Kenting reef, southern Taiwan between July 2008 and November 2009. Among the 10 sites, four of them lie along the warm water discharge from the outlet of the 3rd nuclear power plant of Taiwan Power Corporation, where average seawater temperature is 1.0-3.0ºC higher than that compared to adjacent reefs sites. A noncoding intergenic region between COI and the formylmethionine transfer RNA gene (IGR) of the mitochondrial genome and the region of ITS1, 5.8S, and partial ITS2 ribosomal DNA showed there is no population subdivision in P. verweyi of Kenting reef. Molecular phylotyping showed P. verweyi to be associated with Symbiodinium D1a and C3, either solely or in combination in the areas of warm water discharge. While in those sites away from the outlet, this coral species associated only with subclade C3. The proportion of subclade C3 gradually decreased and D1a became dominant while the sites closer to the source of warm water discharge. The result indicated anthropogenic constant elevated seawater temperature might have influenced the Symbiodinium composition in P. verweyi at the Outlet of Kenting reef.
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