DOI: 10.1111/gbi.12279
Scopus记录号: 2-s2.0-85045670402
论文题名: Tracing the fate of steroids through a hypersaline microbial mat (Kiritimati, Kiribati/Central Pacific)
作者: Shen Y. ; Thiel V. ; Duda J.-P. ; Reitner J.
刊名: Geobiology
ISSN: 1472-4677
EISSN: 1472-4669
出版年: 2018
卷: 16, 期: 3 起始页码: 307
结束页码: 318
语种: 英语
英文关键词: eukaryotes
; mat-seal effect
; organic biomarkers
; preservational pathways
; pyrolysis
; taphonomy
Scopus关键词: bacterium
; biomarker
; burial diagenesis
; eukaryote
; hypersaline environment
; lake
; lipid
; microbial activity
; microbial mat
; organic matter
; preservative
; pyrolysis
; steroid
; taphonomy
; Kiribati
; Kiritimati
; Line Islands
; Pacific Ocean
; Pacific Ocean (Central)
; Eukaryota
Scopus学科分类: Earth and Planetary Sciences: General Earth and Planetary Sciences
; Environmental Science: General Environmental Science
; Agricultural and Biological Sciences: Ecology, Evolution, Behavior and Systematic
英文摘要: Eukaryotic steranes are typically absent or occur in very low concentrations in Precambrian sedimentary rocks. However, it is as yet unclear whether this may reflect low source inputs or a preservational bias. For instance, it has been proposed that eukaryotic lipids were profoundly degraded in benthic microbial mats that were ubiquitous prior to the advent of vertical bioturbation in the Cambrian (“mat-seal effect”). It is therefore important to test the microbial turnover and degradation of eukaryotic steroids in real-world microbial mats. Here we assessed steroid inventories in different layers of a microbial mat from a hypersaline lake on Kiritimati (Central Pacific). Various eukaryote-derived C27-C30 steroids were detected in all mat layers. These compounds most likely entered the mat system as unsaturated sterols from the water column or the topmost mat, and were progressively altered during burial in the deeper, anoxic mat layers over c. 103 years. This is reflected by increasing proportions of saturated sterols and sterenes, as well as the presence of thiosteranes in certain horizons. Sterol alteration can partly be assigned to microbial transformation but is also due to chemical reactions promoted by the reducing environment in the deeper mat layers. Notably, however, compounds with a sterane skeleton were similarly abundant in all mat layers and their absolute concentrations did not show any systematic decrease. The observed decrease of steroid/hopanoid ratios with depth may thus rather indicate a progressive “dilution” by lipids derived from heterotrophic bacteria. Further, pyrolysis revealed that steroids, in contrast to hopanoids, were not sequestered into non-extractable organic matter. This may lead to a preservational bias against steroids during later stages of burial. Taken together, steroid preservation in the microbial mat is not only controlled by heterotrophic degradation, but rather reflects a complex interplay of taphonomic processes. © 2018 John Wiley & Sons Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/85011
Appears in Collections: 影响、适应和脆弱性
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作者单位: Department of Geobiology, Geoscience Centre, Georg-August-Universität Göttingen, Göttingen, Germany; ‘Origin of Life’ Group, Göttingen Academy of Sciences and Humanities, Göttingen, Germany
Recommended Citation:
Shen Y.,Thiel V.,Duda J.-P.,et al. Tracing the fate of steroids through a hypersaline microbial mat (Kiritimati, Kiribati/Central Pacific)[J]. Geobiology,2018-01-01,16(3)