Themechanism of soil nitrogen transformation under different biocrusts to warming and reduced precipitation: From microbial functional genes to enzyme activity
Themechanism of soil nitrogen transformation under different biocrusts to warming and reduced precipitation: From microbial functional genes to enzyme activity
复制标题
不同生物结皮下土壤氮素转化对变暖和降水减少的机制：从微生物功能基因到酶活性
DOI：
10.1016/j.scitotenv.2020.137849
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发表时间：
2020-06-20
影响因子：
9.8
通讯作者：
Su, Xue
中科院分区：
文献类型：
--
作者：
Hu, Rui;Wang, Xin-ping;Su, Xue
土壤氮素矿化是一种微生物介导的土壤地球化学过程，受气候变化的强烈影响。然而，很少有信息可用于背后的机制，N矿化的长期变暖加上干旱的生物结壳覆盖的土壤中的反应。我们使用开顶箱来研究土壤氮转化率（氨化，硝化和矿化），酶活性和基因丰度，以应对三年（2016-2018）的变暖和降水减少。暖干胁迫显著降低了苔藓覆盖土壤的氮素转化速率、胞外酶活性和基因丰度。然而，对于蓝藻覆盖的土壤，它抑制了酶的活性，增加了硝化相关基因的丰度，从而提高了硝化速率。各处理对裸地土壤氮素转化和酶活性无明显影响，但降低了基因丰度。生物结皮可以促进氮素转化，而气候变暖引起的苔藓结皮的退化会抑制生物结皮对地下微生物群落的调节作用。此外，地下微生物群落可以通过抑制氨化和硝化相关基因家族，并通过刺激蓝藻覆盖土壤中涉及的硝化相关基因家族，在持续变暖和降水减少的情况下介导氮转化。这项研究提供了一个基础，确定在温带沙漠生态系统中的N循环的关键过程中所涉及的功能基因，我们的研究结果进一步突出了不同的生物结壳生物在温带沙漠中的N循环的重要性，因为地球变得越来越热，越来越干燥。(C)2020由Elsevier B. V.出版
Soil nitrogen (N) mineralization is a microbially-mediated biogeochemical process that is strongly influenced by changing climates. However, little information is available on the mechanisms behind the response of N mineralization to prolonged warming coupled with drought in soils covered by biocrusts. We used open top chambers to investigate the rate of soil N transformation (ammonification, nitrification and mineralization), enzyme activity and gene abundance in response to warming coupled with reduced precipitation over three years (2016-2018). Warming and drought significantly reduced the N transformation rate, extracellular enzyme activity, and gene abundance in moss-covered soil. For cyanobacteria-covered soil, however, it inhibited enzyme activity and increased the abundance of the nitrification-related genes and therefore nitrification rate. Our treatments had no obvious effects on N transformation and enzyme activity, but reduced gene abundance in bare soil. Biocrusts may facilitate N transformation while the degradation of moss crust caused by climate warming will dampen any regulating effect of biocrusts on the belowground microbial community. Furthermore, belowground microbial communities can mediate N transformation under ongoing warming and reduced precipitation by suppressing ammonification- and nitrification-related gene families, and by stimulating nitrification-related gene families involved in cyanobacteria-covered soil. This study provides a basis for identifying the functional genes involved in key processes in the N cycle in temperate desert ecosystems, and our results further highlight the importance of different biocrusts organisms in the N cycle in temperate deserts as Earth becomes hotter and drier. (C) 2020 Published by Elsevier B.V.