TY - JOUR
T1 - Anaerobic oxidation of methane in coastal sediment from Guishan Island (Pearl River Estuary), South China Sea
AU - Wu, Zijun
AU - Zhou, Huaiyang
AU - Peng, Xiaotong
AU - Jia, Nan
AU - Wang, Yuhong
AU - Yuan, Linxi
N1 - Funding Information:
We thank the shipboard scientists, captain, and crew of the R/V Haijian 83 for their excellent support during the South China Sea cruise in March, 2006. We thank Dr Liu Jinzhong for his assistance in analyzing the stable carbon isotopes of methane and CO2. We would also like to thank Dr Tina Treude and an anonymous reviewer for their very helpful comments on the manuscript. This research was supported by the National Basic Research Project (Grant No. G200007850), National Natural Science Foundation of China (Grant No. 40803020) and the Opening Foundation of State Key Laboratory of Marine Geology, Tongji University (Grant No. MG0807).
PY - 2008
Y1 - 2008
N2 - The concentrations of CH4, SO42-, ΣCO2 and the carbon isotope compositions of ΣCO2 and CH4 in the pore-water of the GS sedimentary core collected from Guishan Island (Pearl River Estuary), South China Sea, were determined. The methane concentration in the pore-water shows dramatic changes and sulfate concentration gradients are linear at the base of the sulfate reduction zone for the station. The carbon isotope of methane becomes heavier at the sulfate-methane transition (SMT) likely because of the Raleigh distillation effect; 12CH4 was oxidized faster than 13CH4, and this caused the enrichment of residual methane δ13C and δ 13C-ΣCO2 minimum. The geochemical profiles of the pore-water support the existence of anaerobic oxidation of methane (AOM), which is mainly controlled by the quality and quantity of the sedimentary organic matter. As inferred from the index of δ13C-TOC value and TOC/TN ratio, the organic matter is a mix of mainly refractory terrestrial component plus some labile alga marine-derived in the study area. A large amount of labile organic matter (mainly labile alga marine-derived) is consumed via the process of sedimentary organic matter diagenesis, and this reduces the amount of labile organic matter incorporated into the base of the sulfate reduction zone. Due to the scarcity of labile organic matter, the sulfate will in turn be consumed by its reaction with methane and therefore AOM takes place. Based on a diffussion model, the portion of pore-water sulfate reduction via AOM is 58.6%, and the percentage of ΣCO2 in the pore-water derived from AOM is 41.4%. Thus, AOM plays an important role in the carbon and sulfur cycling in the marine sediments of Pearl River Estuary.
AB - The concentrations of CH4, SO42-, ΣCO2 and the carbon isotope compositions of ΣCO2 and CH4 in the pore-water of the GS sedimentary core collected from Guishan Island (Pearl River Estuary), South China Sea, were determined. The methane concentration in the pore-water shows dramatic changes and sulfate concentration gradients are linear at the base of the sulfate reduction zone for the station. The carbon isotope of methane becomes heavier at the sulfate-methane transition (SMT) likely because of the Raleigh distillation effect; 12CH4 was oxidized faster than 13CH4, and this caused the enrichment of residual methane δ13C and δ 13C-ΣCO2 minimum. The geochemical profiles of the pore-water support the existence of anaerobic oxidation of methane (AOM), which is mainly controlled by the quality and quantity of the sedimentary organic matter. As inferred from the index of δ13C-TOC value and TOC/TN ratio, the organic matter is a mix of mainly refractory terrestrial component plus some labile alga marine-derived in the study area. A large amount of labile organic matter (mainly labile alga marine-derived) is consumed via the process of sedimentary organic matter diagenesis, and this reduces the amount of labile organic matter incorporated into the base of the sulfate reduction zone. Due to the scarcity of labile organic matter, the sulfate will in turn be consumed by its reaction with methane and therefore AOM takes place. Based on a diffussion model, the portion of pore-water sulfate reduction via AOM is 58.6%, and the percentage of ΣCO2 in the pore-water derived from AOM is 41.4%. Thus, AOM plays an important role in the carbon and sulfur cycling in the marine sediments of Pearl River Estuary.
KW - Anaerobic oxidation of methane (AOM)
KW - Pore-water
KW - South China Sea
KW - Sulfate reduction
UR - http://www.scopus.com/inward/record.url?scp=63249105468&partnerID=8YFLogxK
U2 - 10.1007/s12040-008-0078-y
DO - 10.1007/s12040-008-0078-y
M3 - Article
AN - SCOPUS:63249105468
SN - 0253-4126
VL - 117
SP - 935
EP - 943
JO - Journal of Earth System Science
JF - Journal of Earth System Science
IS - 6
ER -
