Assessment of shallow methane (CH4) gas using stable carbon and hydrogen isotopes in the sediments of the Gunsan Basin, eastern-central Yellow Sea, off the southwest of Korea

Title
Assessment of shallow methane (CH4) gas using stable carbon and hydrogen isotopes in the sediments of the Gunsan Basin, eastern-central Yellow Sea, off the southwest of Korea
Author(s)
이준호; 정갑식; 우한준; 강정원; Urumu Tsunogai
KIOST Author(s)
Lee, Jun Ho(이준호)Woo, Han Jun(우한준)Kang, Jeong Won(강정원)
Alternative Author(s)
이준호; 정갑식; 우한준; 강정원
Publication Year
2016-12-12
Abstract
In the Gunsan Basin, eastern-central Yellow Sea (YS), gas seepages were observed from the uppermost sedimentary layer charged locally with gases that are important indicators of marine resources, environmental changes, and geo-hazards. Methane (CH4) among the gases is the most abundant organic compound in the Earth’s atmosphere, where it acts as a greenhouse gas and thus has implications for global climate change. Headspace CH4 was determined in surface and core sediments in order to understand the C- and H- isotopes signatures in the Gunsan Basin that were collected onboard R/V Onnuri and Eardo in 2013 to 2015. The surface sediments contain 0.2 to 16.9 µ M CH4 that are mostly produced by microbial fermentation of organic materials in shallow depth, as indicated by the light values of δ13CCH4 (– 70.2~-50.7‰ VPDB). CH4 is actively seeping mainly in the western central part of the Gunsan Basin where the underlying sedimentary layers are thick and heavily faulted. In the cores, CH4 is concentrated 1 to 20 μM through the core depths without any relationships to grain size, organic matter contents. Largely different from those, δ13CCH4 ranges in – 62.0~-18.0‰ VPDB (δ2DCH4 range in – 296.0~-144.0‰ VSMOW), that is, strongly mixed CH4 of thermogenic and biogenic origins in the core sediments. The CH4 flux at the sediment-water interface (SWI) using Fick’s first law of diffusion was calculated 2~2ane (CH4) among the gases is the most abundant organic compound in the Earth’s atmosphere, where it acts as a greenhouse gas and thus has implications for global climate change. Headspace CH4 was determined in surface and core sediments in order to understand the C- and H- isotopes signatures in the Gunsan Basin that were collected onboard R/V Onnuri and Eardo in 2013 to 2015. The surface sediments contain 0.2 to 16.9 µ M CH4 that are mostly produced by microbial fermentation of organic materials in shallow depth, as indicated by the light values of δ13CCH4 (– 70.2~-50.7‰ VPDB). CH4 is actively seeping mainly in the western central part of the Gunsan Basin where the underlying sedimentary layers are thick and heavily faulted. In the cores, CH4 is concentrated 1 to 20 μM through the core depths without any relationships to grain size, organic matter contents. Largely different from those, δ13CCH4 ranges in – 62.0~-18.0‰ VPDB (δ2DCH4 range in – 296.0~-144.0‰ VSMOW), that is, strongly mixed CH4 of (중략)
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/24258
Bibliographic Citation
2016 American Geophysical Union (AGU), pp.1 - 2, 2016
Publisher
2016 AGU Fall Meeting
Type
Conference
Language
English
Publisher
2016 AGU Fall Meeting
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