- 學位論文
探討地點、季節與深度對鐘形微孔珊瑚及萼形柱珊瑚的共棲菌相影響
Influences of location, season and depth on coral-associated bacterial composition in Porites lutea and Stylophora pistillata
摘要
珊瑚礁是海洋中生物多樣性最高的生態系之一，當中為生態系關鍵物種的珊瑚，其研究格外受注目。近年來因人類活動導致全球氣候改變，多數研究指出海洋動物會隨著環境改變而遷移到適合生存的環境，但採取固著型生活方式的珊瑚卻難以主動遷移棲地，而可能是以改變其共棲微生物的組成來適應環境上的變動。過往研究已知環境因子的改變，像是溫度，會對珊瑚共棲的微生物族群造成影響，其中珊瑚共棲菌是由珊瑚宿主還是環境主導仍還不夠清楚。台灣位於東亞季風帶上及橫跨熱帶及亞熱帶，並且部分海域為黑潮流經處，有著差異甚大的海洋環境，產生了多樣的珊瑚礁棲地。因此，本研究以調查石珊瑚之菌相在不同珊瑚礁棲地中的差異，希望了解主導珊瑚共棲菌的是宿主還是環境。我們針對台灣亞熱帶（東北角）與熱帶（綠島）兩處，於兩季節（冬末/夏末） 採集兩種台灣常見石珊瑚–萼柱珊瑚 （Stylophora pistillata） 及鐘形微孔珊瑚 （Porites lutea）其中綠島更針對不同深度 （10/40米）進行比較，抽取珊瑚體上的DNA，針對細菌之16S rDNA分析珊瑚共棲菌相組成差異，並結合各項環境參數和珊瑚生理數值，分析與菌相差異的關聯性。根據結果得知珊瑚宿主差異是最主要影響共棲菌相組成的因子，其次為地點之差異，接著是季節與深度等因素。從本研究的結果了解，石珊瑚的共棲菌組成結構可能是由珊瑚宿主主導。另外，藉由了解台灣東北角及綠島珊瑚共棲菌相的差異性，可幫助日後研究不同季風帶之珊瑚共棲體適應環境變動時的策略。
並列摘要
The coral reef ecosystem has the highest biodiversity among all marine ecosystems. Like all the ecosystems suffering from climate change, the coral reef is greatly impacted. Mobile species can migrate but corals can only acclimatize through incorporating with various microorganisms. Previous studies suggested the environmental factors have influences on coral microbiome dynamics. It is still not clear the driving factors of the changes in coral microbiome composition. Taiwan locates at the Tropic of Cancer, across the tropical and subtropical regions, with the Kuroshio Currents which create a diversified marine environment. Therefore, we can test corals in both tropical and subtropical regions to understand the coral microbiome composition in different habitats and seasons and determine the leading factor of the change in the microbiome. In this study, we examined the bacteria community composition of Stylophora pistillata and Porites lutea in 10m and 40m depth from Northern Taiwan and Green Island with two sampling points at the end of summer and winter. The bacterial communities were analyzed using V6-V8 region of the 16S rDNA gene, and analyzed with environmental factors and coral physiology parameters. The major factor that affected the bacterial community is the coral host, the second factor is the location and then seasons and depths. This result suggests the coral microbiome composition is determined by coral host species. The locational difference in the coral bacterial community could help us to understand how the coral microbiome can adapt in different regions.