Millennial-age glycerol dialkyl glycerol tetraethers (GDGTs) in forested mineral soils: 14C-based evidence for stabilization of microbial necromass

doi:10.5194/bg-18-189-2021

GSTDTAP > 资源环境科学

DOI	10.5194/bg-18-189-2021
	Millennial-age glycerol dialkyl glycerol tetraethers (GDGTs) in forested mineral soils: 14C-based evidence for stabilization of microbial necromass
	admin
	2021-01-29
出版年	2021
国家	欧洲
领域	气候变化 ; 资源环境
英文摘要	Understanding controls on the persistence of soil organic matter (SOM) is essential to constrain its role in the carbon cycle and inform climate–carbon cycle model predictions. Emerging concepts regarding the formation and turnover of SOM imply that it is mainly comprised of mineral-stabilized microbial products and residues; however, direct evidence in support of this concept remains limited. Here, we introduce and test a method for the isolation of isoprenoid and branched glycerol dialkyl glycerol tetraethers (GDGTs) – diagnostic membrane lipids of archaea and bacteria, respectively – for subsequent natural abundance radiocarbon analysis. The method is applied to depth profiles from two Swiss pre-Alpine forested soils. We find that the Δ14C values of these microbial markers markedly decrease with increasing soil depth, indicating turnover times of millennia in mineral subsoils. The contrasting metabolisms of the GDGT-producing microorganisms indicates it is unlikely that the low Δ14C values of these membrane lipids reflect heterotrophic acquisition of 14C-depleted carbon. We therefore attribute the 14C-depleted signatures of GDGTs to their physical protection through association with mineral surfaces. These findings thus provide strong evidence for the presence of stabilized microbial necromass in forested mineral soils.
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来源平台	European Geosciences Union
引用统计
文献类型	科技报告
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/314097
专题	资源环境科学气候变化
推荐引用方式 GB/T 7714	admin. Millennial-age glycerol dialkyl glycerol tetraethers (GDGTs) in forested mineral soils: 14C-based evidence for stabilization of microbial necromass,2021.