동해 울릉분지 가스하이드레이트 부존지역에서의

Abstract

Gas hydrate has an importance as new alternative energy in the future and it is necessary to understand microorganism activity related to the production and consumption of the gas hydrate and methane biogeochemical cycle. In this study, we investigated origin and composition of sedimentary organic matter related to the production of gas hydrate in the gas hydrate-bearing core sediment(St.12-2) and non bearing core sediment(St.21) using carbon and nitrogen stable isotope ratio and C/N ratio. In addition, the methane related biomarker abundances and their 13C isotopic signatures were determined in the sediment of both cores. Our study showed that the core sediment at St.12-2 has higher concentration of each AOM biomarker than St.21. Also, the biomarker peaks are coincided with bacteria community structure of delta-proteobacteria in 12-2 core, demonstrating that sulfate-methane transition zone should be corresponded to the sediment core depth (130cm~180cm). In 12-2 core, the stable carbon isotope of methane indicates mostly biogenic origin. Archaeol / sn-2-hydroxyarchaeol ratio shows that in this interval, ANME-1 consortium was dominated in the corresponding interval.