Distribution of tetraether lipids in agricultural soils – differentiation between paddy and upland management
Distribution of tetraether lipids in agricultural soils – differentiation between paddy and upland management
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DOI：
10.5194/bg-13-1647-2016
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发表时间：
2015-10
期刊：
影响因子：
4.9
通讯作者：
Cornelia Mueller-Niggemann;S. Utami;A. Marxen;K. Mangelsdorf;T. Bauersachs;L. Schwark
中科院分区：
文献类型：
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作者：
Cornelia Mueller-Niggemann;S. Utami;A. Marxen;K. Mangelsdorf;T. Bauersachs;L. Schwark
抽象的。稻田几乎占全球耕地的五分之一，为世界一半以上的人口提供主食。与此同时，它们是甲烷的主要来源，因此对目前地球大气变暖起到了重要作用。然而，尽管它们在碳和其他元素的循环中具有明显的重要性，但在稻田中茁壮成长的微生物在生物分子方面的特征还不够充分。几乎没有关于人类通过不同的管理类型(例如，影响土壤或水的氧化还原条件、种植的植物)改变水稻土壤中自然微生物群落的生物分子的信息。在这里，我们测定了不同土地利用类型对作为微生物群落结构分子指示剂的甘油二烷基甘油四醚(GDGTS)在稻田(周期性淹水)和邻近旱地(非淹水)土壤中的分布的影响，并进一步比较了森林、灌丛和沼泽土壤。为了区分不同地区对GDGT分布格局的影响，我们收集了热带(印度尼西亚、越南和菲律宾)和亚热带(中国和意大利)地点的土壤样本。我们发现，异戊二烯GDGT(IGDGT)和分枝GDGT(BrGDGT)的分布差异主要受管理类型的控制，其次受气候变化的影响。一般而言，旱地土壤中的古细菌酚含量高于水稻土，而水稻土中GDGT-0的含量则更为丰富。水稻土的GDGT-0/考古酚比值表明产甲烷古生菌的存在增强，是其他土壤的3-27倍，并随着水稻种植周期的增加而增加。旱地、灌丛和森林土壤中86个碳组成的四醚指数(TEX86)是水稻土的1.3倍，这可能是由于土壤温度的差异。在所有土壤中，brGDGT占优势，从亚热带土壤到热带土壤，brGDGT的相对丰度逐渐增加。与旱地土壤相比，水稻土中较高的分枝四醚(BIT)值，以及亚热带气候土壤中较高的BIT值，表明不同的管理和气候条件对brGDGT的数量有影响。在酸性土壤中，支链四醚环化率(CBT)值与土壤pH值有很好的相关性。然而，在中性到碱性土壤中，水稻和旱地管理土壤之间的CBT没有相关性，而是存在偏移。这被解释为表明土壤水分对这些土壤中的CBT施加了额外的控制。与旱地土壤相比，水稻土中支链四醚的修正甲基化指数(MBT‘)和由此计算出的温度(TMC)较低，这归因于管理诱导(例如，通过淹水增加土壤水分)对年平均土壤温度(MST)的影响。
Abstract. Rice paddies constitute almost a fifth of global cropland and provide more than half of the world's population with staple food. At the same time, they are a major source of methane and therewith significantly contribute to the current warming of Earth's atmosphere. Despite their apparent importance in the cycling of carbon and other elements, however, the microorganisms thriving in rice paddies are insufficiently characterized with respect to their biomolecules. Hardly any information exists on human-induced alteration of biomolecules from natural microbial communities in paddy soils through varying management types (affecting, e.g., soil or water redox conditions, cultivated plants). Here, we determined the influence of different land use types on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs), which serve as molecular indicators for microbial community structures, in rice paddy (periodically flooded) and adjacent upland (non-flooded) soils and, for further comparison, forest, bushland and marsh soils. To differentiate local effects on GDGT distribution patterns, we collected soil samples in locations from tropical (Indonesia, Vietnam and Philippines) and subtropical (China and Italy) sites. We found that differences in the distribution of isoprenoid GDGTs (iGDGTs) as well as of branched GDGTs (brGDGTs) are predominantly controlled by management type and only secondarily by climatic exposition. In general, upland soil had higher crenarchaeol contents than paddy soil, which by contrast was more enriched in GDGT-0. The GDGT-0 ∕ crenarchaeol ratio, indicating the enhanced presence of methanogenic archaea, was 3–27 times higher in paddy soils compared to other soils and increased with the number of rice cultivation cycles per year. The index of tetraethers consisting of 86 carbons (TEX86) values were 1.3 times higher in upland, bushland and forest soils than in paddy soils, potentially due to differences in soil temperature. In all soils brGDGT predominated over iGDGTs with the relative abundance of brGDGTs increasing from subtropical to tropical soils. Higher branched vs. isoprenoid tetraether (BIT) values in paddy soils compared to upland soils together with higher BIT values in soils from subtropical climates indicated effects on the amounts of brGDGT induced by differences in management as well as climate. In acidic soils cyclization ratio of branched tetraethers (CBT) values correlated well with soil pH. In neutral to alkaline soils, however, no correlation but an offset in CBT between paddy and upland managed soils was detected. This is interpreted as indicating soil moisture exerting an additional control on the CBT in these soils. Lower modified methylation index of branched tetraether (MBT′) values and temperatures calculated from this (TMC) in paddy soils compared to upland soils are attributed to a management-induced (e.g. enhanced soil moisture via flooding) effect on mean annual soil temperature (MST).