Nitrogen fertilization has a stronger effect on soil nitrogen-fixing bacterial communities than elevated atmospheric CO2.

Journal Article (Journal Article)

Biological nitrogen fixation is the primary supply of N to most ecosystems, yet there is considerable uncertainty about how N-fixing bacteria will respond to global change factors such as increasing atmospheric CO2 and N deposition. Using the nifH gene as a molecular marker, we studied how the community structure of N-fixing soil bacteria from temperate pine, aspen, and sweet gum stands and a brackish tidal marsh responded to multiyear elevated CO2 conditions. We also examined how N availability, specifically, N fertilization, interacted with elevated CO2 to affect these communities in the temperate pine forest. Based on data from Sanger sequencing and quantitative PCR, the soil nifH composition in the three forest systems was dominated by species in the Geobacteraceae and, to a lesser extent, Alphaproteobacteria. The N-fixing-bacterial-community structure was subtly altered after 10 or more years of elevated atmospheric CO2, and the observed shifts differed in each biome. In the pine forest, N fertilization had a stronger effect on nifH community structure than elevated CO2 and suppressed the diversity and abundance of N-fixing bacteria under elevated atmospheric CO2 conditions. These results indicate that N-fixing bacteria have complex, interacting responses that will be important for understanding ecosystem productivity in a changing climate.

Full Text

Duke Authors

Cited Authors

  • Berthrong, ST; Yeager, CM; Gallegos-Graves, L; Steven, B; Eichorst, SA; Jackson, RB; Kuske, CR

Published Date

  • May 2014

Published In

Volume / Issue

  • 80 / 10

Start / End Page

  • 3103 - 3112

PubMed ID

  • 24610855

Pubmed Central ID

  • PMC4018900

Electronic International Standard Serial Number (EISSN)

  • 1098-5336

International Standard Serial Number (ISSN)

  • 0099-2240

Digital Object Identifier (DOI)

  • 10.1128/aem.04034-13


  • eng