干旱区生态环境知识资源中心(Arid): Variation of branched tetraethers with soil depth in relation to non-temperature factors: Implications for paleoclimate reconstruction

Arid

DOI	10.1016/j.chemgeo.2021.120211
	Variation of branched tetraethers with soil depth in relation to non-temperature factors: Implications for paleoclimate reconstruction
	Pei, Hongye; Zhao, Shijin; Yang, Huan; Xie, Shucheng
通讯作者	Yang, H (corresponding author), China Univ Geosci, Sch Geog & Informat Engn, Hubei Key Lab Crit Zone Evolut, Wuhan 430074, Peoples R China.
来源期刊	CHEMICAL GEOLOGY
ISSN	0009-2541
EISSN	1872-6836
出版年	2021
卷号	572
英文摘要	Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that have been extensively used as tools for paleoclimate reconstruction. Temperature and pH were thought to be two major factors affecting the distributions of brGDGTs; however, the effects of other factors on the distribution of brGDGTs and related temperature and pH proxies in soil environments remain unclear. Here, we investigated iso- and br-GDGT distributions in three soil profiles (SPs) developed on bedrocks consisting of hornfels (HP), granite (GP), and basalt (BP), respectively. The downward environmental factors in these SPs differ, thus providing a chance to evaluate their effects on the distribution of brGDGTs. In the three SPs, the methylation degree for 5-methyl and total brGDGTs (MBT?5ME and MBT?), respectively, varied significantly downwards despite minor changes in soil temperature, highlighting a non-temperature effect. The depth-dependence of these proxies appears to be caused by the oxygen level. The MBT? for 5- or 6-methyl brGDGTs (MBT?5ME and MBT?6ME), or total brGDGTs (MBT?), increased as the oxygen level decreased, suggesting tetramethylated brGDGTs (Ia, Ib, and Ic) would increase in abundance with decreased oxygen level. The two pH proxies, CBT and IR6ME, both decreased at lower oxygen levels. Such regulation of brGDGT compositions in response to oxygen availability could be explained by the changing bacterial communities that have different oxygen preferences. The possible oxygen level impact on the distribution of GDGTs could result in brGDGT-inferred temperature skewed towards higher values and pH towards lower values with decreased oxygen level. This finding may also have implications for the mechanism of soil aridity impact on the brGDGT-based proxies in semi-arid and arid regions, which is of profound importance for paleotemperature and hydroclimate reconstruction in loess-paleosol sequences. Increasing soil aridity could lead to changes in brGDGT-based proxies similar to that observed at the higher oxygen level, i.e., lower MBT?, higher CBT, and higher IR6ME. As soil aridity is generally associated with better aeration and higher oxygen level, we argue that changes in oxygen level might be the real cause of the bias in brGDGT-based proxies in soils from semi-arid and arid regions.
英文关键词	Soil profiles Oxygen level GDGTs Proxies Paleoclimate reconstruction
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000643802900003
WOS关键词	DIALKYL GLYCEROL TETRAETHERS ; BACTERIAL COMMUNITY STRUCTURE ; CHINA IMPLICATIONS ; INTACT POLAR ; MEMBRANE-LIPIDS ; ENVIRONMENTAL VARIABLES ; PARTICULATE MATTER ; OXYGEN ; PH ; CORE
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/349831
作者单位	[Pei, Hongye; Zhao, Shijin; Xie, Shucheng] China Univ Geosci, Sch Earth Sci, State Key Lab Biogeol & Environm Geol, Wuhan 430074, Peoples R China; [Yang, Huan] China Univ Geosci, Sch Geog & Informat Engn, Hubei Key Lab Crit Zone Evolut, Wuhan 430074, Peoples R China
推荐引用方式 GB/T 7714	Pei, Hongye,Zhao, Shijin,Yang, Huan,et al. Variation of branched tetraethers with soil depth in relation to non-temperature factors: Implications for paleoclimate reconstruction[J],2021,572.
APA	Pei, Hongye,Zhao, Shijin,Yang, Huan,&Xie, Shucheng.(2021).Variation of branched tetraethers with soil depth in relation to non-temperature factors: Implications for paleoclimate reconstruction.CHEMICAL GEOLOGY,572.
MLA	Pei, Hongye,et al."Variation of branched tetraethers with soil depth in relation to non-temperature factors: Implications for paleoclimate reconstruction".CHEMICAL GEOLOGY 572(2021).