Ma Xiuyan, Song Yanyu, Song Changchun, Wang Xianwei, Wang Nannan, Gao Siqi, Cheng Xiaofeng, Liu Zhendi, Gao Jinli, Du Yu
Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
University of Chinese Academy Sciences, Beijing 100049, China.
Microorganisms. 2021 Dec 2;9(12):2498. doi: 10.3390/microorganisms9122498.
Nitrogen is the limiting nutrient for plant growth in peatland ecosystems. Nitrogen addition significantly affects the plant biomass, diversity and community structure in peatlands. However, the response of belowground microbe to nitrogen addition in peatland ecosystems remains largely unknown. In this study, we performed long-term nitrogen addition experiments in a permafrost peatland in the northwest slope of the Great Xing'an Mountains. The four nitrogen addition treatments applied in this study were 0 g N·m·year (CK), 6 g N·m·year (N1), 12 g N·m·year (N2), and 24 g N·m·year (N3). Effects of nitrogen addition over a period of nine growing seasons on the soil microbial abundance and community diversity in permafrost peatland were analyzed. The results showed that the abundances of soil bacteria, fungi, archaea, nitrogen-cycling genes (H and b-A), and A increased in N1, N2, and N3 treatments compared to CK. This indicated that nitrogen addition promoted microbial decomposition of soil organic matter, nitrogen fixation, ammonia oxidation, nitrification, and methane production. Moreover, nitrogen addition altered the microbial community composition. At the phylum level, the relative abundance of Proteobacteria increased significantly in the N2 treatment. However, the relative abundances of Actinobacteria and Verrucifera in the N2 treatment and Patescibacteria in the N1 treatment decreased significantly. The heatmap showed that the dominant order composition of soil bacteria in N1, N2, and N3 treatments and the CK treatment were different, and the dominant order composition of soil fungi in CK and N3 treatments were different. The N1 treatment showed a significant increase in the Ace and Chao indices of bacteria and Simpson index of fungi. The outcomes of this study suggest that nitrogen addition altered the soil microbial abundance, community structure, and diversity, affecting the soil microbial carbon and nitrogen cycling in permafrost peatland. The results are helpful to understand the microbial mediation on ecological processes in response to N addition.
氮是泥炭地生态系统中植物生长的限制养分。添加氮显著影响泥炭地的植物生物量、多样性和群落结构。然而，泥炭地生态系统中地下微生物对添加氮的响应仍 largely 未知。在本研究中，我们在大兴安岭西北坡的多年冻土泥炭地进行了长期添加氮实验。本研究应用的四种添加氮处理分别为 0 g N·m·年（CK）、6 g N·m·年（N1）、12 g N·m·年（N2）和 24 g N·m·年（N3）。分析了九个生长季的添加氮对多年冻土泥炭地土壤微生物丰度和群落多样性的影响。结果表明，与 CK 相比，N1、N2 和 N3 处理中土壤细菌、真菌、古菌、氮循环基因（H 和 b - A）以及 A 的丰度增加。这表明添加氮促进了土壤有机质的微生物分解、固氮、氨氧化、硝化作用和甲烷产生。此外，添加氮改变了微生物群落组成。在门水平上，N2 处理中变形菌门的相对丰度显著增加。然而，N2 处理中放线菌门和疣微菌门以及 N1 处理中 Patescibacteria 的相对丰度显著降低。热图显示，N1、N2 和 N3 处理以及 CK 处理中土壤细菌的优势目组成不同，CK 和 N3 处理中土壤真菌的优势目组成不同。N1 处理中细菌的 Ace 和 Chao 指数以及真菌的辛普森指数显著增加。本研究结果表明，添加氮改变了土壤微生物丰度、群落结构和多样性，影响了多年冻土泥炭地土壤微生物碳和氮循环。这些结果有助于理解微生物对添加氮响应的生态过程的介导作用。
