干旱区生态环境知识资源中心(Arid): Xeropreservation of Functionalized Lipid Biomarkers in Hyperarid Soils in the Atacama Desert.

Arid

报告编号	N180001603
	Xeropreservation of Functionalized Lipid Biomarkers in Hyperarid Soils in the Atacama Desert.
	Wilhelm, M. B; Davila, A. F; Williams, A; Eigenbrode, J. L; Parenteau, M. N; Jahnke, L. L; Liu, X; Summons, R. E; Wray, J. J; Stamos, B. N; O’Reilly, S. S.
英文摘要	Our understanding of long-term organic matter preservation comes mostly from studies in aquatic systems. In contrast, taphonomic processes in extremely dry environments are relatively understudied and are poorly understood. We investigated the accumulation and preservation of lipid biomarkers in hyperarid soils in the Yungay region of the Atacama Desert. Lipids from seven soil horizons in a 2.5 meter vertical profile were extracted and analyzed using GC-MS ( Gas Chromatography-Mass Spectrometry) and LC-MS (Liquid Chromatography-Mass Spectrometry). Diagnostic functionalized lipids and geolipids were detected and increased in abundance and diversity with depth. Deeper clay units contain fossil organic matter (radiocarbon dead) that has been protected from rainwater since the onset of hyperaridity. We show that these clay units contain lipids in an excellent state of structural preservation with functional groups and unsaturated bonds in carbon chains. This indicates that minimal degradation of lipids has occurred in these soils since the time of their deposition between more than 40,000 and up to 2 million years ago. The exceptional structural preservation of biomarkers is likely due to the long-term hyperaridity that has minimized microbial and enzymatic activity, a taphonomic process we term xeropreservation (i.e. preservation by drying). The degree of biomarker preservation allowed us to reconstruct major changes in ecology in the Yungay region that reflect a shift in hydrological regime from wet to dry since the early Quaternary. Our results suggest that hyperarid environments, which comprise 7.5 percent of the continental landmass, could represent a rich and relatively unexplored source of paleobiological information on Earth.
英文关键词	Preserving (conservation) Lipids Biomarkers Arid lands Soils Drying Clays Atacama desert Organic materials Fatty acids Microorganisms Molecular structure Mass spectroscopy Chromatography Paleobiology Mars (planet) Chile
出版年	2016
语种	英语
国家	United States
来源学科分类	57 - Medicine & Biology
URL	http://r.cnki.net/KCMS/detail/detail.aspx?DbCode=KJBG&dbname=KJBGW&filename=5b2aea8231c97d0b6414e216
来源机构	National Aeronautics and Space Administration
资源类型	科技报告
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/274037
推荐引用方式 GB/T 7714	Wilhelm, M. B,Davila, A. F,Williams, A,et al. Xeropreservation of Functionalized Lipid Biomarkers in Hyperarid Soils in the Atacama Desert.,2016.