Environmental controls on bacterial tetraether membrane lipid distribution in soils
Environmental controls on bacterial tetraether membrane lipid distribution in soils
复制标题
DOI：
10.1016/j.gca.2006.10.003
复制
发表时间：
2007-02-01
影响因子：
5
通讯作者：
Damste, Jaap S. Sinninghe
中科院分区：
文献类型：
--
作者：
Weijers, Johan W. H.;Schouten, Stefan;Damste, Jaap S. Sinninghe
近年来，在泥炭沼泽和土壤中发现了一类新型的支链甘油二烷基甘油四醚（GDGT）膜脂。它们由具有4-6个连接到正烷基链的甲基和烷基链中的0 - 2个环戊基部分的组分组成。这些分支的膜脂是由一组迄今未知的厌氧土壤细菌产生的。在这项研究中，我们分析了134个土壤样品的分支膜脂含量从全球分布的90个地点，研究控制不同的分支GDGT异构体的相对分布的环境因素。我们的研究结果表明，环戊基部分的相对量，表示在环化率的支链四醚（CBT），主要是有关土壤的pH值（R（2）= 0.70），而不是温度（R（2）= 0.03）。甲基支链的相对量，表示在支链四醚（MBT）的甲基化指数，是正相关的年平均气温（MAT）（R（2）= 0.62），并在较小程度上，负相关的土壤pH值（R（2）= 0.37）。然而，如果将这两个参数结合起来，则似乎MBT的变化在很大程度上由MAT和pH值解释（R（2）= 0.82）。这些结果表明，土壤衍生GDGT膜脂的相对分布可用于古环境研究，以估计过去的年度MAT和土壤pH值。All rights reserved.
Over the last years a novel group of branched glycerol dialkyl glycerol tetraether (GDGT) membrane lipids has been discovered in peat bogs and soils. They consist of components with 4-6 methyl groups attached to the n-alkyl chains and 0 to 2 cyclopentyl moieties in the alkyl chain. These branched membrane lipids are produced by an as yet unknown group of anaerobic soil bacteria. In this study we analysed the branched membrane lipid content of 134 soil samples from 90 globally distributed locations to study the environmental factors controlling the relative distribution of the different branched GDGT isomers. Our results show that the relative amount of cyclopentyl moieties, expressed in the cyclisation ratio of branched tetraethers (CBT), is primarily related to the pH of the soil (R(2) = 0.70) and not to temperature (R(2) = 0.03). The relative amount of methyl branches, expressed in the methylation index of branched tetraethers (MBT), is positively correlated with the annual mean air temperature (MAT) (R(2) = 0.62) and, to a lesser extent, negatively correlated with the pH of the soil (R(2) = 0.37). If both parameters are combined, however, it appears that the variation in the MBT is largely explained by both MAT and pH (R(2) = 0.82). These results suggest that the relative distribution of soil-derived GDGT membrane lipids can be used in palaeoenvironmental studies to estimate past annual MAT and soil pH. (c) 2006 Elsevier Inc. All rights reserved.