Effects of elevated atmospheric CO2 on rhizosphere soil microbial communities in a Mojave Desert ecosystem

Document Type

Article

Publication Date

3-2011

Publication Title

Journal of Arid Environments

Volume

75

First page number:

917

Last page number:

925

Abstract

The effects of elevated atmospheric carbon dioxide [CO2] on microbial communities in arid rhizosphere soils beneath Larrea tridentata were examined. Roots of Larrea were harvested from plots fumigated with elevated or ambient levels of [CO2] using Free-Air CO2 Enrichment (FACE) technology. Twelve bacterial and fungal rRNA gene libraries were constructed, sequenced and categorized into operational taxonomical units (OTUs). There was a significant decrease in OTUs within the Firmicutes (bacteria) in elevated [CO2], and increase in Basiomycota (fungi) in rhizosphere soils of plots exposed to ambient [CO2]. Phylogenetic analyses indicated that OTUs belonged to a wide range of bacterial and fungal taxa. To further study changes in bacterial communities, Quantitative Polymerase Chain Reaction (QPCR) was used to quantify populations of bacteria in rhizosphere soil. The concentration of total bacteria 16S rDNA was similar in conditions of enriched and ambient [CO2]. However, QPCR of Gram-positive microorganisms showed a 43% decrease in the population in elevated [CO2]. The decrease in representation of Gram positives and the similar values for total bacterial DNA suggest that the representation of other bacterial taxa was promoted by elevated [CO2]. These results indicate that elevated [CO2] changes structure and representation of microorganisms associated with roots of desert plants.

Keywords

Arid rhizosphere soil; Atmospheric carbon dioxide; Bacterial communities; Carbon dioxide—Physiological effect; FACE; Fungal communities; Microbial ecology

Disciplines

Desert Ecology | Geochemistry | Other Earth Sciences | Soil Science

Language

English


Search your library

Share

COinS