Welcome to Acta Oceanologica Sinica!

Set as Homepage | Add to favorites

DING Ling,ZHAO Meixun,YU Meng,LI Li,HUANG Chi-Yue. 2017. Biomarker assessments of sources and environmental implications of organic matter in sediments from potential cold seep areas of the northeastern South China Sea. Acta Oceanologica Sinica, 36(10):8－19

Biomarker assessments of sources and environmental implications of organic matter in sediments from potential cold seep areas of the northeastern South China Sea

南海东北部冷泉区沉积物中有机质来源的生物标志物分析与环境指示意义

Received:April 13, 2016

DOI：10.1007/s13131-017-1068-1

Key words:biomarkers organic matter sources TOM MOM anaerobic oxidation of methane South China Sea

中文关键词: 生物标志物有机质来源陆源有机质海源有机质甲烷厌氧氧化南海

基金项目:

Author Name	Affiliation	E-mail
DING Ling	Key Laboratory of Marine Chemistry Theory and Technology(Ocean University of China), Ministry of Education, Qingdao 266100, China Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Ministry of Land and Resources, Qingdao 266071, China
ZHAO Meixun	Key Laboratory of Marine Chemistry Theory and Technology(Ocean University of China), Ministry of Education, Qingdao 266100, China	maxzhao@ouc.edu.cn
YU Meng	Key Laboratory of Marine Chemistry Theory and Technology(Ocean University of China), Ministry of Education, Qingdao 266100, China
LI Li	Key Laboratory of Marine Chemistry Theory and Technology(Ocean University of China), Ministry of Education, Qingdao 266100, China
HUANG Chi-Yue	Department of Earth Sciences, National Cheng Kung University, Tainan 701, Taiwan, China

Hits: 3288

Download times: 1996

Abstract:

Multi-biomarker indexes were analyzed for two piston cores from potential cold seep areas of the South China Sea off southwestern Taiwan. Total organic carbon (TOC) normalized terrestrial (n-alkanes) and marine (brassicasterol, dinosterol, alkenones and iso-GDGTs) biomarker contents and ratios (TMBR, 1/P_mar-aq, BIT) were used to evaluate the contributions of terrestrial and marine organic matter (TOM and MOM respectively) to the sedimentary organic matter, indicating that MOM dominated the organic sources in Core MD052911 and the sedimentary organic matter in Core ORI-860-22 was mainly derived from terrestrial inputs, and different morphologies were the likely reason for TOM percentage differences. BIT results suggested that river-transported terrestrial soil organic matter was not a major source of TOM of sedimentary organic matter around these settings. Diagnostic biomarkers for methane-oxidizing archaea (MOA) were only detected in one sample at 172 cm depth of Core ORI-860-22, with abnormally high iso-GDGTs content and Methane Index (MI) value (0.94). These results indicated high anaerobic oxidation of methane (AOM) activities at or around 172 cm in Core ORI-860-22. However in Core MD052911, MOA biomarkers were not detected and MI values were lower (0.19-0.38), indicated insignificant contributions of iso-GDGTs from methanotrophic archaea and the absence of significant AOM activities. Biomarker results thus indicated that the discontinuous upward methane seepage and insufficient methane flux could not induce high AOM activities in our sampling sites. In addition, the different patterns of TEX₈₆ and U₃₇^K' temperature in two cores suggested that AOM activities affected TEX₈₆ temperature estimates with lower values in Core ORI-860-22, but not significantly on TEX₈₆ temperature estimates in Core MD052911.

中文摘要:

本文对台湾西南部南海冷泉区的2个沉积物岩心进行了多参数生物标志物分析。利用总有机碳标准化的陆源生物标志物（长链正构烷烃）和海源生物标志物（菜子甾醇、甲藻甾醇、长链烯酮和iso-GDGTs）的含量与比值（TMBR，1/P_mar-aq，BIT）指示陆源有机质（TOM）与海源有机质（MOM）对沉积总有机质的相对贡献。结果显示，MD052911岩心以海源有机质为主，ORI-860-22岩心的沉积有机质则主要来自于陆源输入；2个站位不同的地形形态可能是导致陆源有机质比例存在差异的原因。BIT指标的结果显示河流输入的陆地土壤有机质并不是这一区域沉积有机质中陆源有机质的主要来源。甲烷氧化古菌（MOA）的特征生物标志物仅在ORI-860-22岩心172 cm深度处的一个样品中被检测到，且样品有着异常高的iso-GDGTs含量和MI值（Methane Index，0.94）；而在MD052911岩心中并未检测到MOA生物标志物且MI值较低。结果表明，ORI-860-22岩心172 cm深度附近发生了明显的甲烷厌氧氧化过程（AOM）；而MD052911岩心中甲烷氧化古菌对iso-GDGTs贡献较低，不存在明显的甲烷厌氧氧化作用。不连续的甲烷溢出和较低的甲烷通量并不能引起甲烷的厌氧氧化过程。此外，2个岩心不同的TEX₈₆和U₃₇^K'温度分布表明，甲烷厌氧氧化作用导致ORI-860-22岩心较低的TEX₈₆温度，而对MD052911岩心的TEX₈₆温度结果没有明显影响。

HTML View Full Text View/Add Comment Download reader