Long-term elevated CO2 shifts composition of soil microbial communities in a Californian annual grassland, reducing growth and N utilization potentials

Sihang Yang, Qiaoshu Zheng, Mengting Yuan, Zhou Shi, Nona R. Chiariello, Kathryn M. Docherty, Shikui Dong, Christopher B. Field, Yunfu Gu, Jessica Gutknecht, Bruce A. Hungate, Xavier Le Roux, Xingyu Ma, Audrey Niboyet, Tong Yuan, Jizhong Zhou, Yunfeng Yang

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


The continuously increasing concentration of atmospheric CO2 has considerably altered ecosystem functioning. However, few studies have examined the long-term (i.e. over a decade) effect of elevated CO2 on soil microbial communities. Using 16S rRNA gene amplicons and a GeoChip microarray, we investigated soil microbial communities from a Californian annual grassland after 14 years of experimentally elevated CO2 (275 ppm higher than ambient). Both taxonomic and functional gene compositions of the soil microbial community were modified by elevated CO2. There was decrease in relative abundance for taxa with higher ribosomal RNA operon (rrn) copy number under elevated CO2, which is a functional trait that responds positively to resource availability in culture. In contrast, taxa with lower rrn copy number were increased by elevated CO2. As a consequence, the abundance-weighted average rrn copy number of significantly changed OTUs declined from 2.27 at ambient CO2 to 2.01 at elevated CO2. The nitrogen (N) fixation gene nifH and the ammonium-oxidizing gene amoA significantly decreased under elevated CO2 by 12.6% and 6.1%, respectively. Concomitantly, nitrifying enzyme activity decreased by 48.3% under elevated CO2, albeit this change was not significant. There was also a substantial but insignificant decrease in available soil N, with both nitrate (NO3 ) (−27.4%) and ammonium (NH4 +) (−15.4%) declining. Further, a large number of microbial genes related to carbon (C) degradation were also affected by elevated CO2, whereas those related to C fixation remained largely unchanged. The overall changes in microbial communities and soil N pools induced by long-term elevated CO2 suggest constrained microbial N decomposition, thereby slowing the potential maximum growth rate of the microbial community.

Original languageEnglish (US)
Pages (from-to)1474-1481
Number of pages8
JournalScience of the Total Environment
StatePublished - Feb 20 2019


  • Annual grassland
  • Elevated CO
  • GeoChip
  • MiSeq sequencing
  • Microbial communities

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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