Organic carbon availability limiting microbial denitrification in the deep vadose zone
Organic carbon availability limiting microbial denitrification in the deep vadose zone
复制标题
有机碳的有效性限制了深渗流区的微生物反硝化
DOI：
10.1111/1462-2920.14027
复制
发表时间：
2018-03-01
影响因子：
5.1
通讯作者：
Liu, Binbin
中科院分区：
文献类型：
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作者：
Chen, Shuaimin;Wang, Fenghua;Liu, Binbin
深渗流区的微生物在减缓硝酸盐淋滤方面发挥着重要作用；然而，由于采样困难，关于微生物反硝化机制的信息有限。我们通过实验研究了沿土壤剖面收集到 10.5 米深的土壤中影响反硝化作用的因素。缺氧预孵化后，反硝化率适度增加，N2 O/(N2 O + N2 )比值下降，而大多数层的微生物丰度和多样性没有显着变化。所有研究层中有机碳的可用性增加，反硝化速率显着增强，反硝化基因的丰度同时提高，地下层的程度高于表层，这表明深层渗流带碳严重缺乏。假单胞菌属和芽孢杆菌属由许多先前已被确定为土壤中反硝化菌的物种组成，是对碳添加做出反应的主要分类群。总的来说，我们的结果表明，深渗流区反硝化作用有限并不是因为反硝化菌的缺乏，而是因为碳利用率较低而导致反硝化菌丰度较低。
Microbes in the deep vadose zone play an essential role in the mitigation of nitrate leaching; however, limited information is available on the mechanisms of microbial denitrification due to sampling difficulties. We experimentally studied the factors that affect denitrification in soils collected down to 10.5 meters deep along the soil profile. After an anoxic pre-incubation, denitrification rates moderately increased and the N2 O/(N2 O + N2 ) ratios declined while the microbial abundance and diversity did not change significantly in most of the layers. Denitrification rate was significantly enhanced and the abundance of the denitrification genes was simultaneously elevated by the increased availability of organic carbon in all studied layers, to a greater extent in the subsurface layers than in the surface layers, suggesting the severe scarcity of carbon in the deep vadose zone. The genera Pseudomonas and Bacillus, which are made up of a number of species that have been previously identified as denitrifiers in soil, were the major taxa that respond to carbon addition. Overall, our results suggested that the limited denitrification in the deep vadose zone is not because of the lack of denitrifiers, but due to the low abundance of denitrifiers which is caused by low carbon availability.