Rate-specific responses of prokaryotic diversity and structure to nitrogen deposition in the Leymus chinensis steppe

• Published in: Soil biology & biochemistry Vol. 79; pp. 81 - 90
• Main Authors: Yao, Minjie, Rui, Junpeng, Li, Jiabao, Dai, Yumei, Bai, Yongfei, Heděnec, Petr, Wang, Junming, Zhang, Shiheng, Pei, Kequan, Liu, Chi, Wang, Yanfen, Zhili He, Frouz, Jan, Li, Xiangzhen
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.12.2014; Elsevier
• Subjects: Acidobacteria; Agronomy. Soil science and plant productions; bacteria; bacterial communities; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; China; Community structure; Copiotrophic bacteria; Diversity; eutrophication; Fundamental and applied biological sciences. Psychology; Leymus chinensis; N deposition; nitrogen; Oligotrophic bacteria; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Proteobacteria; respiratory quotient; soil acidification; soil pH; Soil science; species diversity; Steppe ecosystem; steppes; terrestrial ecosystems; Verrucomicrobia; Verrucomicrobium; China, People's Rep., Inner Mongolia; China, People's Rep; China; Community structure; Copiotrophic bacteria; Oligotrophic bacteria; N deposition; Steppe ecosystem; Diversity; Monocotyledones; Perennial plant; Nitrogen; Gramineae; Steppe; Ecosystem; Angiospermae; Bacteria; Prokaryote; Herbaceous plant; Spermatophyta; Soil science; Fodder crop; Oligotrophy; Deposition
• DOI: 10.1016/j.soilbio.2014.09.009
• ISSN: 0038-0717

Serious nitrogen (N) deposition in terrestrial ecosystems causes soil acidification and changes the structure and function of the microbial community. However, it is unclear how these changes are dependent on N deposition rates, other factors induced by N (e.g., pH), and their interactions. In this study, we investigated the responses of soil prokaryotic community structure and stability after a 13-year N addition in the semi-arid Leymus chinensis steppe in Inner Mongolia, China. Our results demonstrated that the prokaryotic community structure changed at the low N addition rate of 1.75 g N m−2 yr−1; however, dramatic changes in microbial abundance, respiratory quotient, and prokaryotic diversity occurred at N addition rates of more than 5.25 g N m−2 yr−1 when the soil pH dropped below 6.0. The two patterns indicated the difference in driving forces for different microbial properties. The N-driven and pH-driven processes are likely the most important mechanisms determining the responses of bacterial community to N. Some copiotrophic/oligotrophic bacteria, e.g., Proteobacteria and Acidobacteria, changed their relative abundances with the N addition continuously even at a low rate, indicating that they were more sensitive to N directly. Some bacterial groups significantly changed their relative abundance at a high N addition rate when pH dropped below 6.0, e.g., Verrucomicrobia and Armatimonadetes, indicating that they were more sensitive to pH below 6.0. N addition altered the prokaryotic community structure through enrichment of copiotrophic bacteria (species adjustment) at low N addition rates and through enrichment of nitrophilous taxa and significant loss of diversity at high N rates. The results also demonstrated that a high N addition diminished the stability of the prokaryotic community structure and activity through reduction in species diversity and bacterial interaction. Overall, this study supported the hypothesis that the responses of prokaryota to N were dependent on deposition rates, and N-driven and pH-driven processes were the important mechanisms to control the shift of the prokaryotic community. •The responses of prokaryota to nitrogen are dependent on deposition rates.•Nitrogen-driven and pH-driven processes are important mechanisms.•Prokaryota changes dramatically when pH drops below 6.0 at high N deposition rates.•High N deposition simplifies the microbial interaction network.•High N deposition diminishes the stability of prokaryotic community structure.