臺灣墾丁海域維氏腦紋珊瑚的宿主族群遺傳與共生藻組成

Host genetic and Symbiodinium composition in brain coral, Platygyra verweyi in Kenting, southern Taiwan

藍家宏(Chia-Hung Lan)

指導教授 ： 陳昭倫

國立臺灣大學/理學院/海洋研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.10570

摘要

未來造礁珊瑚能倖免於全球氣候暖化的海洋，與耐熱型共生藻共生被視為有潛力的重要機制之一。研究顯示珊瑚藉由與耐熱型共生藻D1a共生能在溫度變動極大的環境，如潮池、潮間帶等地區中存活。本研究從2008年7月到2009年11月間，採集南台灣墾丁十個地點 1至3米海域的維氏腦紋珊瑚（Platygyra verweyi）。在這十個地點中，有四個點的海水溫度比起周圍珊瑚礁環境平均高了1.0到3.0ºC，與台電核三廠溫水排放口的距離有關。族群遺傳利用粒腺體基因的非編碼區(noncoding region)及核醣體的轉錄區間(ITS)進行分析,結果顯示不同地點的族群並沒有分化的現象。共生藻系群分析結果顯示維氏腦紋珊瑚在溫水排放的地點與D1a及C3系群共生藻單獨或是同時共生,但沒有溫水影響的地點則主要與C3系群共生藻共生。當珊瑚在越接近溫水排放口時，C3系群共生藻的比例越低，最後變成以D1a系群共生藻為主。結果指出人為造成的海水溫度上升可能影響了維氏腦紋珊瑚在墾丁出水口海域的體內共生藻組成。

關鍵字

維氏腦紋珊瑚 ； D1a系群共生藻 ； 耐熱型 ； 溫水排放

並列摘要

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.

並列關鍵字

Platygyra verweyi ； Symbiodinium D1a ； heat-tolerance ； thermal water discharge

參考文獻

Abrego D, Ulstrup KE, Willis BL, van Oppen MJH (2008) Species-specific interactions between algal endosymbionts and coral hosts define their bleaching response to heat and light stress. Proc Royal Soc London B, 275, 2273-2282.

Arnason E, Palsson S (1996) Mitochondrial cytochrome b DNA sequence variation of Atlantic cod, Gadus morhua, from Norway. Mol Ecol, 5, 715-724

Ayre DJ, Dufty S (1994) Evidence for restricted gene flow in the viviparous coral Seriatopora hystrix on Australia's Great Barrier Reef. Evolution, 48(4), 1183-1201.

Baird AH, Bhagooli R, et al. (2009) Coral bleaching. The role of the host. Trends Ecol Evol, 24, 16-20.

Baker AC (2003a) Flexibility and specifcity in coral-algal symbiosis: diversity, ecology, and biogeography of Symbiodinium. Annu Rev Ecol Syst, 34, 661-689.