Glucose-stimulation of natural microbial activity changes composition, structure and engineering properties of sandy and loamy soils
Glucose-stimulation of natural microbial activity changes composition, structure and engineering properties of sandy and loamy soils
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DOI：
10.1016/j.enggeo.2019.105381
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发表时间：
2020-02-01
影响因子：
7.4
通讯作者：
Totsche, Kai Uwe
中科院分区：
文献类型：
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作者：
Ivanov, Pavel;Manucharova, Natalia;Totsche, Kai Uwe
向地下大量输入容易获得的有机物质可能会迅速激活本地微生物群落，从而改变土壤工程特性。我们在实验室实验中进行了超过 30 天的研究，研究了添加葡萄糖（一种容易获得的碳源）对几种壤质和沙质土壤的应力应变特性、矿物学和微观结构的影响。在微生物高度活动期间，直接剪切测试显示摩擦角减少了 15-30%，沙子的内聚力增加。无侧限压缩试验表明，壤土的抗压强度下降了 20-30%。随着微生物活性的下降，应力应变特性部分恢复。随着微生物活性的增加，应力-应变特性的变化与矿物学和成分的变化有关。 X射线衍射结果表明，伊利石-蒙脱石混层矿物中蒙脱石层的比例增加，粘土矿物整体缺陷增多。添加葡萄糖导致微团聚体含量暂时增加（0.1-0.05 mm）。通过扫描电子显微镜观察固体颗粒之间有机物新形成的连接、生物膜的形成以及细胞与矿物表面的直接相互作用。我们的数据表明，微生物介导的过程可能会对土壤的应力应变特性产生不利影响，并危及建筑物的安全。
High inputs of easily available organic matter to the subsurface may quickly activate the native microbial communities, thereby changing soil engineering properties. We studied the effect of glucose addition, an easily available carbon source, on stress-strain properties, mineralogy, and microstructure of several loamy and sandy soils over 30 days in laboratory experiments. During the period of high microbial activity, direct shear tests revealed a reduction of the friction angle of 15-30 % and a raise of cohesion in sands. Unconfined compression tests showed a 20-30 % decrease in the compressive strength of loamy soils. With the decline of microbial activity, the stress-strain properties recovered partially. The alterations of the stress-strain properties with increasing microbial activity were linked to changes in mineralogy and composition. X-ray diffraction showed that the proportion of smectite layers in illite-smectite mixed layer minerals increased, as well as the overall imperfection of clay minerals. Glucose addition resulted in a temporary increase in the content of microaggregates (0.1-0.05 mm). Newly formed linkages of organic matter between solid particles, biofilm formation and direct interaction of cells with mineral surfaces were observed by scanning electron microscopy. Our data show that microbial-mediated processes may adversely influence stress-strain properties of soils and endanger the safety of buildings.