Changes in Nitrogen-Fixing and Ammonia-Oxidizing Bacterial Communities in Soil of a Mixed Conifer Forest after Wildfire
Changes in Nitrogen-Fixing and Ammonia-Oxidizing Bacterial Communities in Soil of a Mixed Conifer Forest after Wildfire
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DOI：
10.1128/aem.71.5.2713-2722.2005
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发表时间：
2005-05
影响因子：
4.4
通讯作者：
C. Yeager;D. Northup;Christy C. Grow;S. M. Barns;C. Kuske
中科院分区：
文献类型：
--
作者：
C. Yeager;D. Northup;Christy C. Grow;S. M. Barns;C. Kuske
本研究旨在探讨森林火灾对土壤中两类重要的氮循环细菌--固氮菌和氨氧化菌的影响。nifH和amoA PCR扩增子的序列和末端限制性片段长度多态性（T-RFLP）分析进行未燃烧，中度烧伤，严重烧伤的混合针叶林土壤的DNA样品。PCR结果表明，火烧迹地土壤生物量和固氮、氨氧化物种比例低于未火烧迹地。占主导地位的nifH序列类型的数量是更大的火灾影响的土壤中，和nifH序列，最密切相关的孢子形成类群梭菌和类芽孢杆菌在燃烧的土壤中更丰富。在氨氧化社区的T-RFLP模式，终端限制性片段（TRFs）代表amoA集群1，2，或4亚硝化螺旋体属。占主导地位（80至90%），在未燃烧的土壤中，而TRFs代表amoA集群3A亚硝化螺菌属。在火灾影响的土壤中占主导地位（65%至95%）。亚硝化螺旋菌属（Nitrosospira spp.）序列类型与土壤pH值（5.6 ~ 7.5）和NH_3-N含量（0.002 ~ 0.976ppm）呈显著正相关。在火灾后14个月收集的受火灾影响的土壤中，微生物生物量的减少和固氮和氨氧化群落的变化仍然很明显。
ABSTRACT This study was undertaken to examine the effects of forest fire on two important groups of N-cycling bacteria in soil, the nitrogen-fixing and ammonia-oxidizing bacteria. Sequence and terminal restriction fragment length polymorphism (T-RFLP) analysis of nifH and amoA PCR amplicons was performed on DNA samples from unburned, moderately burned, and severely burned soils of a mixed conifer forest. PCR results indicated that the soil biomass and proportion of nitrogen-fixing and ammonia-oxidizing species was less in soil from the fire-impacted sites than from the unburned sites. The number of dominant nifH sequence types was greater in fire-impacted soils, and nifH sequences that were most closely related to those from the spore-forming taxa Clostridium and Paenibacillus were more abundant in the burned soils. In T-RFLP patterns of the ammonia-oxidizing community, terminal restriction fragments (TRFs) representing amoA cluster 1, 2, or 4 Nitrosospira spp. were dominant (80 to 90%) in unburned soils, while TRFs representing amoA cluster 3A Nitrosospira spp. dominated (65 to 95%) in fire-impacted soils. The dominance of amoA cluster 3A Nitrosospira spp. sequence types was positively correlated with soil pH (5.6 to 7.5) and NH3-N levels (0.002 to 0.976 ppm), both of which were higher in burned soils. The decreased microbial biomass and shift in nitrogen-fixing and ammonia-oxidizing communities were still evident in fire-impacted soils collected 14 months after the fire.