title: The soil microbiome at the Gi-FACE experiment responds to a moisture gradient but not to CO2 enrichment.
abstract: The soil bacterial community at the Giessen free-air CO2 enrichment (Gi-FACE) experiment was analysed by tag sequencing of the 16S rRNA gene. No substantial effects of CO2 levels on bacterial community composition were detected. However, the soil moisture gradient at Gi-FACE had a significant effect on bacterial community composition. Different groups within the Acidobacteria and Verrucomicrobia phyla were affected differently by soil moisture content. These results suggest that modest increases in atmospheric CO2 may cause only minor changes in soil bacterial community composition and indicate that the functional responses of the soil community to CO2 enrichment previously reported at Gi-FACE are due to factors other than changes in bacterial community composition. The effects of the moisture gradient revealed new information about the relationships between poorly known Acidobacteria and Verrucomicrobia and soil moisture content. This study contrasts with the relatively small number of other temperate grassland free-air CO2 enrichment microbiome studies in the use of moderate CO2 enrichment and the resulting minor changes in the soil microbiome. Thus, it will facilitate the development of further climate change mitigation studies. In addition, the moisture gradient found at Gi-FACE contributes new knowledge in soil microbial ecology, particularly regarding the abundance and moisture relationships of the soil Verrucomicrobia.
authors.affiliation: Peel Building, School of Environment & Life Sciences, University of Salford, Salford M5 4WT, UK.
authors.forename: Alexandre B
authors.initials: AB
authors.lastname: de Menezes
authors.affiliation: School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland.|Department of Plant Ecology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Müller
authors.affiliation: School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Clipson
authors.affiliation: School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Doyle
mesh_terms: D000388:Air / Q000032:analysis*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism*; D064307:Microbiota; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D014867:Water / Q000032:analysis* / Q000378:metabolism
chemical_list: D012987:Soil; D014867:Water; D002245:Carbon Dioxide