科研之友
微信
新浪微博
Facebook
分享链接
摘要
All forest fire events generate some quantity of charcoal, which may persist in sods for hundreds to thousands of years. However, few studies have effectively evaluated the potential for charcoal to influence specific microbial communities or processes To our knowledge, no studies have specifically addressed the effect of charcoal on ammonia-oxidizing bacteria (AOB) in forest soils Controlled experiments have shown that charcoal amendment of fire-excluded temperate and boreal coniferous forest sod increases net nitrification, suggesting that charcoal plays a major role in maintaining nitrification for extended periods postfire. In this study, we examined the influence of fire history on gross nitrification, mtrification potential, and the nature and abundance of AOB Soil cores were collected from sites in the Selway-Butterroor wilderness area in northern Idaho that had been exposed twice (in 1910, 1934) or three times (1910, 1934, and 1992) in the last 94 yr, allowing us to contrast sods recently exposed to fire to those that experienced no recent fire (control). Charcoal content was determined in the O horizon by hand-separation and in the mineral soil by a chemical digestion procedure Gross and net nitrification, and potential rates of nitrification were measured in mineral soil. Analysis of the AOB community was conducted using primer sets specific for the ammonia mono-oxygenase gene (amoA) or the 16S rRNA gene of AOB Denaturing gradient gel electrophoresis was used to analyze the AOB community structure, while AOB abundance was determined by quantitative polymerase chain reaction Recent (12-yr-old) wildfire resulted in greater charcoal contents and nitrification rates compared with sites without fire for 75 yr, and the more recent fire appeared to have directly influenced AOB abundance and community structure. We predicted and observed greater abundance of AOB in soils recently exposed to fire compared with control soils. Interestingly, sequence data revealed that Clusters 3 and 4, and not Cluster 2, of genus Nitrosospira dominated these forest soils, with a shift toward Cluster 3 in recently burned sues
- 出版日期2010-8
