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Schleuss, Per-Marten ; Widdig, Meike ; Biederman, L. A. ; Borer, E. T. ; Crawley, M. J. ; Kirkman, K. P. ; Seabloom, E. W. ; Wragg, P. D. ; Spohn, Marie:
Microbial substrate stoichiometry governs nutrient effects on nitrogen cycling in grassland soils.
In: Soil Biology & Biochemistry.
Bd. 155
(2021)
.
- 108168.
ISSN 0038-0717
DOI: https://doi.org/10.1016/j.soilbio.2021.108168
Abstract
Human activities have increased nitrogen (N) and phosphorus (P) inputs in terrestrial ecosystems and altered carbon (C) availability, shifting the stoichiometry of microbial substrates in soils, such as the C:N:P ratios of the dissolved organic matter pool. These stoichiometric deviations between microbial biomass and its substrate may control microbial processes of N cycling. We studied the effects of this stoichiometric mismatch using a full factorial N and P addition experiment replicated in six grassland ecosystems in South Africa, the USA, and the UK. We found that N and P addition changed the dissolved organic matter C:N ratio, but not the C:N ratio of the soil microbial biomass. Compared to P addition, N addition decreased microbial N acquisition via non-symbiotic N2 fixation by −55% and increased microbial N release via net N mineralization by +134%. A possible explanation is that the dissolved elements, e.g., dissolved organic C (DOC) and dissolved total N (DN), serve as the main microbial substrate and its C:N ratio defines whether N is scarce or abundant with respect to microbial demands. If N is available in excess relative to microbial demands, net N mineralization increases. In contrast, when N is scarce, immobilization outweighs release decreasing net N mineralization. However, the activity of leucine aminopeptidases, which decompose peptides, was not affected by nutrient additions. Further, C rather than P availability may control the rates of non-symbiotic N2 fixation in the six studied grassland sites. In conclusion, globally increasing nutrient inputs change processes of microbial N acquisition and release in grassland ecosystems and these changes are largely driven by shifts in substrate stoichiometry.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Keywords: | Nitrogen release and acquisition; Net N mineralization; Non-symbiotic N2 fixation; Leucine aminopeptidase activity; Nutrient fertilization; Ecological Stoichiometry; Nutrient Network (NutNet) |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften > Lehrstuhl Bodenökologie Forschungseinrichtungen > Zentrale wissenschaftliche Einrichtungen > Bayreuther Zentrum für Ökologie und Umweltforschung - BayCEER |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften |
| Eingestellt am: | 29 Okt 2024 08:39 |
| Letzte Änderung: | 29 Okt 2024 08:40 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/90876 |