Global grassland diazotrophic communities are structured by combined abiotic, biotic, and spatial distance factors but resilient to fertilization

Autor(en): Maximilian Nepel, Roey Angel, Elizabeth T. Borer, Beat Frey, Andrew S. MacDougall, Rebecca L. McCulley, Anita Risch, Martin Schütz, Eric W. Seabloom, Dagmar Wöbken
Abstrakt: Grassland ecosystems cover around 37% of the ice-free land surface on Earth and have critical socioeconomic importance globally. As in many terrestrial ecosystems, biological dinitrogen (N₂) fixation represents an essential natural source of nitrogen (N). The ability to fix atmospheric N₂ is limited to diazotrophs, a diverse guild of bacteria and archaea. To elucidate the abiotic (climatic, edaphic), biotic (vegetation), and spatial factors that govern diazotrophic community composition in global grassland soils, amplicon sequencing of the dinitrogenase reductase gene—nifH—was performed on samples from a replicated standardized nutrient [N, phosphorus (P)] addition experiment in 23 grassland sites spanning four continents. Sites harbored distinct and diverse diazotrophic communities, with most of reads assigned to diazotrophic taxa within the Alphaproteobacteria (e.g., Rhizobiales), Cyanobacteria (e.g., Nostocales), and Deltaproteobacteria (e.g., Desulforomonadales) groups. Likely because of the wide range of climatic and edaphic conditions and spatial distance among sampling sites, only a few of the taxa were present at all sites. The best model describing the variation among soil diazotrophic communities at the OTU level combined climate seasonality (temperature in the wettest quarter and precipitation in the warmest quarter) with edaphic (C:N ratio, soil texture) and vegetation factors (various perennial plant covers). Additionally, spatial variables (geographic distance) correlated with diazotrophic community variation, suggesting an interplay of environmental variables and spatial distance. The diazotrophic communities appeared to be resilient to elevated nutrient levels, as 2–4 years of chronic N and P additions had little effect on the community composition. However, it remains to be seen, whether changes in the community composition occur after exposure to long-term, chronic fertilization regimes.
Organisation(en): Department für Botanik und Biodiversitätsforschung, Department für Mikrobiologie und Ökosystemforschung
Externe Organisation(en): Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft, University of Guelph, University of Kentucky, University of Minnesota, Twin Cities
Journal: Frontiers in Microbiology
Band: 13
Anzahl der Seiten: 12
ISSN: 1664-302X
DOI: https://doi.org/10.3389/fmicb.2022.821030
Publikationsdatum: 03-2022
Peer-reviewed: Ja
ÖFOS 2012: 106026 Ökosystemforschung, 106022 Mikrobiologie, 106012 Evolutionsforschung, 106042 Systematische Botanik
Schlagwörter
ASJC Scopus Sachgebiete: Microbiology (medical), Microbiology
Sustainable Development Goals: SDG 15 – Leben an Land, SDG 13 – Maßnahmen zum Klimaschutz
Link zum Portal: https://ucris.univie.ac.at/portal/de/publications/global-grassland-diazotrophic-communities-are-structured-by-combined-abiotic-biotic-and-spatial-distance-factors-but-resilient-to-fertilization(82aa7aed-1906-4ed1-b4f1-e5f16f84cd2e).html