title: Elevated CO₂ influences microbial carbon and nitrogen cycling.
abstract: BACKGROUND
  Elevated atmospheric CO₂ (eCO₂) has been shown to have significant effects on terrestrial ecosystems. However, little is known about its influence on the structure, composition, and functional potential of soil microbial communities, especially carbon (C) and nitrogen (N) cycling. A high-throughput functional gene array (GeoChip 3.0) was used to examine the composition, structure, and metabolic potential of soil microbial communities from a grassland field experiment after ten-year field exposure to ambient and elevated CO₂ concentrations.
  
  
  RESULTS
  Distinct microbial communities were established under eCO₂. The abundance of three key C fixation genes encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), carbon monoxide dehydrogenase (CODH) and propionyl-CoA/acetyl-CoA carboxylase (PCC/ACC), significantly increased under eCO₂, and so did some C degrading genes involved in starch, cellulose, and hemicellulose. Also, nifH and nirS involved in N cycling were significantly stimulated. In addition, based on variation partitioning analysis (VPA), the soil microbial community structure was largely shaped by direct and indirect eCO₂-driven factors.
  
  
  CONCLUSIONS
  These findings suggest that the soil microbial community structure and their ecosystem functioning for C and N cycling were altered dramatically at eCO₂. This study provides new insights into our understanding of the feedback response of soil microbial communities to elevated CO₂ and global change.
authors.affiliation: State Key Laboratory of Applied Microbiology, Ministry-Guangdong Province Jointly Breeding Base, South China, Guangdong Institute of Microbiology, Guangzhou, China. xumy@gdim.cn
authors.forename: Meiying
authors.initials: M
authors.lastname: Xu
authors.forename: Zhili
authors.initials: Z
authors.lastname: He
authors.forename: Ye
authors.initials: Y
authors.lastname: Deng
authors.forename: Liyou
authors.initials: L
authors.lastname: Wu
authors.forename: Joy D
authors.initials: JD
authors.lastname: van Nostrand
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Hobbie
authors.forename: Peter B
authors.initials: PB
authors.lastname: Reich
authors.forename: Jizhong
authors.initials: J
authors.lastname: Zhou
mesh_terms: D001419:Bacteria / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D058448:Biota; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D056186:Metagenomics; D046228:Microarray Analysis; D009584:Nitrogen / Q000378:metabolism*; D012988:Soil Microbiology
chemical_list: D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen