Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre and The Cabot Institute, School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
Archaea. 2012;2012:896727. doi: 10.1155/2012/896727. Epub 2012 Nov 22.
Oxic soils typically are a sink for methane due to the presence of high-affinity methanotrophic Bacteria capable of oxidising methane. However, soils experiencing water saturation are able to host significant methanogenic archaeal communities, potentially affecting the capacity of the soil to act as a methane sink. In order to provide insight into methanogenic populations in such soils, the distribution of archaeol in free and conjugated forms was investigated as an indicator of fossilised and living methanogenic biomass using gas chromatography-mass spectrometry with selected ion monitoring. Of three soils studied, only one organic matter-rich site contained archaeol in quantifiable amounts. Assessment of the subsurface profile revealed a dominance of archaeol bound by glycosidic headgroups over phospholipids implying derivation from fossilised biomass. Moisture content, through control of organic carbon and anoxia, seemed to govern trends in methanogen biomass. Archaeol and crenarchaeol profiles differed, implying the former was not of thaumarcheotal origin. Based on these results, we propose the use of intact archaeol as a useful biomarker for methanogen biomass in soil and to track changes in moisture status and aeration related to climate change.
富氧土壤通常是甲烷的汇，因为存在高亲和力的甲烷营养型细菌，能够氧化甲烷。然而，经历水饱和的土壤能够容纳大量的产甲烷古菌群落，这可能会影响土壤作为甲烷汇的能力。为了深入了解这种土壤中的产甲烷菌群，使用气相色谱-质谱联用仪和选择离子监测法，以游离态和共轭态的形式研究了古菌醇的分布情况，将其作为化石和活的产甲烷生物量的指标。在所研究的三种土壤中，只有一个富含有机物的地点含有可量化数量的古菌醇。对地下剖面的评估表明，糖苷头基团结合的古菌醇占主导地位，而不是磷脂，这意味着它来自化石生物量。水分含量通过控制有机碳和缺氧，似乎控制着产甲烷菌生物量的趋势。古菌醇和 crenarchaeol 的分布不同，这意味着前者不是 thaumarcheotal 的起源。基于这些结果，我们建议使用完整的古菌醇作为土壤中产甲烷菌生物量的有用生物标志物，并跟踪与气候变化相关的水分状况和通气变化。
