Chloromethane Degradation in Soils: A Combined Microbial and Two-Dimensional Stable Isotope Approach.
Chloromethane Degradation in Soils: A Combined Microbial and Two-Dimensional Stable Isotope Approach.
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DOI：
10.2134/jeq2017.09.0358
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发表时间：
2018-03
影响因子：
2.4
通讯作者：
Nicole Jaeger;L. Besaury;E. Kröber;A. Delort;M. Greule;K. Lenhart;T. Nadalig;S. Vuilleumier;P. Amato;S. Kolb;F. Bringel;F. Keppler
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作者：
Nicole Jaeger;L. Besaury;E. Kröber;A. Delort;M. Greule;K. Lenhart;T. Nadalig;S. Vuilleumier;P. Amato;S. Kolb;F. Bringel;F. Keppler
氯甲烷（CHCl，methyl chloride）是大气中含量最丰富的挥发性卤代烃，与平流层臭氧消耗有关。全球CHCl收支，特别是土壤中微生物降解CHCl汇，仍然存在很大的不确定性。这些可能通过稳定同位素分析和细菌多样性研究相结合来解决。我们确定了CHCl氢和碳的稳定同位素分馏和CHCl降解过程中的细菌多样性在三种不同性质的土壤（森林，草地和农业土壤），并在不同的温度和顶空混合比的CHCl。氯甲烷降解程度依次为森林>草地>农田土壤。比率范围为0.7至2.5微克/克（干重）。d森林土壤，0.1 - 0.9 μg g干重。d，草地土壤为0.1 ~ 0.4 μg. d随温度升高和CHCl添加量的增加而增加。CHCl的平均稳定富氢因子为-50 ± 13‰，不受温度、混合比或土壤类型的影响。而稳定碳富集因子则取决于CHCl降解速率，范围为-38 ~-11‰。与土壤性质相关的细菌群落组成是独立的CHCl降解或同位素富集。然而，在21个细菌操作分类单位（OTU在97%16S RNA序列同一性水平）中观察到CHCl孵育后丰度增加。这表明，这些细菌类群中的一些，虽然以前没有与CHCl降解，可能发挥作用，在土壤中的微生物CHCl汇。
Chloromethane (CHCl, methyl chloride) is the most abundant volatile halocarbon in the atmosphere and involved in stratospheric ozone depletion. The global CHCl budget, and especially the CHCl sink from microbial degradation in soil, still involves large uncertainties. These may potentially be resolved by a combination of stable isotope analysis and bacterial diversity studies. We determined the stable isotope fractionation of CHCl hydrogen and carbon and investigated bacterial diversity during CHCl degradation in three soils with different properties (forest, grassland, and agricultural soils) and at different temperatures and headspace mixing ratios of CHCl. The extent of chloromethane degradation decreased in the order forest > grassland > agricultural soil. Rates ranged from 0.7 to 2.5 μg g dry wt. d for forest soil, from 0.1 to 0.9 μg g dry wt. d for grassland soil, and from 0.1 to 0.4 μg g dry wt. d for agricultural soil and increased with increasing temperature and CHCl supplementation. The measured mean stable hydrogen enrichment factor of CHCl of -50 ± 13‰ was unaffected by temperature, mixing ratio, or soil type. In contrast, the stable carbon enrichment factor depended on CHCl degradation rates and ranged from -38 to -11‰. Bacterial community composition correlated with soil properties was independent from CHCl degradation or isotope enrichment. Nevertheless, increased abundance after CHCl incubation was observed in 21 bacterial operational taxonomical units (OTUs at the 97% 16S RNA sequence identity level). This suggests that some of these bacterial taxa, although not previously associated with CHCl degradation, may play a role in the microbial CHCl sink in soil.