台灣西南海域活動構造冷泉系統微生物組成之研究

研究冷泉環境中釋放的甲烷對全球碳循環的影響，需要詳細了解微生物群落在不同沉積物環境中的分佈和能力。在本研究中，我們對從台灣西南海域冷泉系統中收集的沉積物岩心進行了基因豐度與微生物多樣性分析。在過去十年中，ROV 或潛水艇等深海技術的進步，使科學家能夠透過進行現地採樣和現地測量來詳細探測冷泉生態系統。這些現地調查顯著增加了我們對生物多樣性的微小變化，以及冷泉生態系統內部之間的生物地球化學活動的了解。我們分析了台灣西南海域甲烷冷泉環境及其他環境條件下的微生物群落結構和組成。冷泉微生物組成複雜多樣，地點間的多樣性大於岩心深度。豐度和族群結構不僅反映了當地地球化學的梯度，而且還受海底特徵或位置的控制。缺氧環境中甲烷的氧化主要由厭氧甲烷氧化 ANME-1b 驅動。此外也發現現了高豐度的 SRB，透過 mcrA 和 dsrB 基因的豐度之間的關係可以確定其與厭氧甲烷氧化菌的關係。總體而言，本研究表明，基因定序與基因豐度的量化和地球化學特徵相結合，將能夠透漏富含甲烷的海洋沉積物中結構複雜的微生物群落，特定群體的詳細分佈和潛在代謝能力。

關鍵字

甲烷；冷泉；甲烷氧化菌

並列摘要

Studying the impacts of methane released from cold seep environments on global carbon cycling would require detailed insights into the distributions and capacities of microbial communities at different environments of sediment. In this study, we conducted gene abundance and diversity analyses for sediment cores retrieved from cold seep systems off southwestern Taiwan. In the last decade, the improvement in deep-sea technologies such as remotely operated vehicles or submersibles enabled the scientist to explore seep ecosystems in detail by performing focused sampling and in situ measurements. These in situ investigations have significantly increased our knowledge of the small scale variability of biodiversity and of biogeochemical activities within and between seep ecosystems. Here we show that the microbial community structure and composition in the local methane seepage other environmental conditions offshore southwestern Taiwan. The composition of microbes in the cold seep is complex and diverse, and the diversities between sites are greater than in depth within the site. Its abundance and composition not only reflect the gradient of the local geochemistry but also controlled by the characteristics or location of the seabed. The oxidation of methane in hypoxic environment was largely driven by archaeal anaerobic methane oxidizers-1b (ANME-1b). Besides, the communities found high abundances of SRB groups reviewed by a clear relationship between the abundance of mcrA and dsrB gene. Overall, this study demonstrates that the sequencing coverage combined with the quantification of gene abundance and geochemical characterization would enable to reveal the detailed distributions and potential metabolic capabilities of specific groups from complexly structured microbial communities in methane-rich marine sediments.