Potential degradation effect on paleo-moisture proxies based on the relative abundance of archaeal vs. bacterial tetraethers in loess-paleosol sequences on the Chinese Loess Plateau

doi:10.1016/j.quaint.2016.11.004

	Potential degradation effect on paleo-moisture proxies based on the relative abundance of archaeal vs. bacterial tetraethers in loess-paleosol sequences on the Chinese Loess Plateau
	Liu, Weiguo 1,2; Lu, Hongxuan 1; Wang, Huanye 1; Zhang, Chuanlun 3
刊名	QUATERNARY INTERNATIONAL
	2017-04-29
卷号	436 期号:2017 页码:173-180
关键词	Gdgt Bit R-i/b Degradation Chinese Loess Plateau
DOI	10.1016/j.quaint.2016.11.004
文献子类	Article
英文摘要	Two indices based on the relative abundance of isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) to branched GDGTs (brGDGTs), i.e., the branched and isoprenoid tetraether (BIT) index and the ratio of isoGDGTs to brGDGTs (RI/b) index, have recently been proposed as promising proxies for tracing humidity variations in terrestrial soil deposits. However, the applicability of these proxies in loess paleosol sequences (LPSs) remains unclear on the Chinese Loess Plateau (CLP). In this study, we analyzed BIT, Ri/b and concentrations of related GDGTs in 37 surface soil samples on the CLP. The results showed that the concentrations of brGDGTs correlate positively (strongly or moderately) with soil water content (SWC; r = 0.74) and mean annual precipitation (MAP; r = 0.58), while the concentrations of isoGDGTs correlate negatively (but generally weakly) with SWC (r = 0.31) and MAP (r = 0.45), and consequently, there is a positive relationship between BIT and moisture, and a negative relationship between Rip, and moisture. Despite the sensitivity of BIT and RI/b to moisture variations on the modern CLP, the published records in 3 LPSs consistently show an increasing trend in BIT and a decreasing trend in Ri/b with age, which are insensitive to past changes in Asian summer monsoon intensity. This fact suggests that the two indices might not be sensitive recorders of past hydrological changes in LPSs on the CLP. Further analysis of GDGT concentrations in the Lantian LPS showed strong and negative exponential relationships between isoGDGT concentrations and age but weak relationships between brGDGT concentrations and age, possibly indicating faster degradation of isoGDGTs vs. brGDGTs in the LPSs. The preferential degradation of isoGDGTs vs. brGDGTs may potentially bias the BIT and Rub indices towards higher and lower values, respectively, and thus might be at least partly responsible for the insensitivity of the two proxies for paleohydrologicial reconstructions in LPSs on the CLP. However, it should be noted that the preferential degradation of isoGDGTs vs. brGDGTs cannot affect other paleoproxies which are based only on isoGDGTs or brGDGTs, such as the TEX86 and MBT'/CBT indices. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.
WOS关键词	DIALKYL GLYCEROL TETRAETHERS ; MONSOON PRECIPITATION ; MEMBRANE-LIPIDS ; AIR-TEMPERATURE ; ORGANIC-MATTER ; SURFACE SOILS ; WATER-CONTENT ; EAST-ASIA ; CLIMATE ; RECONSTRUCTIONS
WOS研究方向	Physical Geography ; Geology
语种	英语
WOS记录号	WOS:000399257200016
内容类型	期刊论文
源URL	[http://ir.ieecas.cn/handle/361006/5484]
专题	地球环境研究所_加速器质谱中心
作者单位	1.Chinese Acad Sci, Inst Earth Environm, State Key Lab Loess & Quaternary Geol, Xian 710061, Peoples R China 2.Xi An Jiao Tong Univ, Sch Human Settlement & Civil Engn, Xian 710049, Peoples R China 3.Tongji Univ, State Key Lab Marine Geol, Shanghai 200092, Peoples R China
推荐引用方式 GB/T 7714	Liu, Weiguo,Lu, Hongxuan,Wang, Huanye,et al. Potential degradation effect on paleo-moisture proxies based on the relative abundance of archaeal vs. bacterial tetraethers in loess-paleosol sequences on the Chinese Loess Plateau[J]. QUATERNARY INTERNATIONAL,2017,436(2017):173-180.
APA	Liu, Weiguo,Lu, Hongxuan,Wang, Huanye,&Zhang, Chuanlun.(2017).Potential degradation effect on paleo-moisture proxies based on the relative abundance of archaeal vs. bacterial tetraethers in loess-paleosol sequences on the Chinese Loess Plateau.QUATERNARY INTERNATIONAL,436(2017),173-180.
MLA	Liu, Weiguo,et al."Potential degradation effect on paleo-moisture proxies based on the relative abundance of archaeal vs. bacterial tetraethers in loess-paleosol sequences on the Chinese Loess Plateau".QUATERNARY INTERNATIONAL 436.2017(2017):173-180.