Dynamics of bacterial communities in relation to soil aggregate formation during the decomposition of ¹³C-labelled rice straw

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• 作者：A. Blaud^a ; ¹ ; T.Z. Lerch^b ; ^c ; ^{thomas.lerch@u-pec.fr} ; T. Chevallier^a ; N. Nunan^b ; C. Chenu^b ; A. Brauman^a
• 关键词：Soil bacterial communities structure ; 13C-labelling ; FAME-SIP ; Soil aggregation ; Mineralisation ; Microscale biogeography
• 刊名：Applied Soil Ecology
• 出版年：2012
• 期刊代码：14_09291393
• 类别：abs
• 出版时间：February, 2012
• 卷：53
• 期：Complete
• 页码：1-9
• 文件大小：826 K

摘要

The addition of fresh organic matter is known to modify both microbial community structure and soil aggregation. The objective of this study was to understand the relationship between the dynamics of the soil microbial community structure in relation to that of their habitats during the decomposition of straw. Soil samples, ground (<200 渭m) to remove macroaggregates, were amended with uniformly ¹³C-labelled powdered rice straw (<500 渭m) and incubated for 21 days. Unamended control samples were also incubated under the same conditions. Total C and rice straw C (C_Straw) mineralised or remaining in different soil fractions (0-50, 50-200, 200-2000 and >2000 渭m) were measured. Fatty acid methyl ester (FAME) profiling was used to determine total bacterial community structure and FAME based stable isotope probing (FAME-SIP) was used to characterise the straw degrader communities. The mineralisation rate of the native C and the C_Straw was high. The formation of macroaggregates (>2000 渭m) occurred within 2 days in amended and unamended samples but did so to a greater extent in the amended samples. The C_Straw was mainly located in fractions >200 渭m, where degraders were the most abundant. The ¹³C-FAME profiles followed the same trends as total FAME profiles through time and within soil fractions, suggesting common dynamics between straw degraders and total bacterial communities: Gram-negative were more important in fraction >200 渭m and during the early stages of the incubation while Gram-positive and actinobacteria dominated in fine fractions and at the end of the incubation. Bacterial community structure changed rapidly (within 2 days) in conjunction with the formation of new microbial habitats, suggesting that the relationship between the two is very close.