Namib Desert primary productivity is driven by cryptic microbial community N-fixation

dc.contributor.authorRamond, Jean-Baptiste
dc.contributor.authorWoodborne, Stephan M.
dc.contributor.authorHall, Grant
dc.contributor.authorSeely, Mary
dc.contributor.authorCowan, Don A.
dc.date.accessioned2018-06-27T08:49:39Z
dc.date.available2018-06-27T08:49:39Z
dc.date.issued2018-05-02
dc.description.abstractCarbon exchange in drylands is typically low, but during significant rainfall events (wet anomalies) drylands act as a C sink. During these anomalies the limitation on C uptake switches from water to nitrogen. In the Namib Desert of southern Africa, the N inventory in soil organic matter available for mineralisation is insufficient to support the observed increase in primary productivity. The C4 grasses that flourish after rainfall events are not capable of N fixation, and so there is no clear mechanism for adequate N fixation in dryland ecosystems to support rapid C uptake. Here we demonstrate that N fixation by photoautotrophic hypolithic communities forms the basis for the N budget for plant productivity events in the Namib Desert. Stable N isotope (δ15N) values of Namib Desert hypolithic biomass, and surface and subsurface soils were measured over 3 years across dune and gravel plain biotopes. Hypoliths showed significantly higher biomass and lower δ15N values than soil organic matter. The δ15N values of hypoliths approach the theoretical values for nitrogen fixation. Our results are strongly indicative that hypolithic communities are the foundation of productivity after rain events in the Namib Desert and are likely to play similar roles in other arid environments.en_ZA
dc.description.departmentBiochemistryen_ZA
dc.description.departmentGeneticsen_ZA
dc.description.departmentMammal Research Instituteen_ZA
dc.description.departmentMicrobiology and Plant Pathologyen_ZA
dc.description.librarianam2018en_ZA
dc.description.sponsorshipThe South African National Research Foundation (Grant number: N00113-95565) and the University of Pretoria (Research and Development Programme for J-BR).en_ZA
dc.description.urihttp://www.nature.com/srepen_ZA
dc.identifier.citationRamond, J.B., Woodborne, S., Hall, G. et al. 2018, 'Namib Desert primary productivity is driven by cryptic microbial community N-fixation', Scientific Reports, vol. 8, art. no. 6921, pp. 1-9.en_ZA
dc.identifier.issn2045-2322 (online)
dc.identifier.other10.1038/s41598-018-25078-4
dc.identifier.urihttp://hdl.handle.net/2263/65248
dc.language.isoenen_ZA
dc.publisherNature Publishing Groupen_ZA
dc.rights© The Author(s) 2018. This article is licensed under a Creative Commons Attribution 4.0 International License.en_ZA
dc.subjectDrylandsen_ZA
dc.subjectRainfallen_ZA
dc.subjectNamib Desert, southern Africaen_ZA
dc.subjectSoilsen_ZA
dc.subjectHoten_ZA
dc.subjectCycleen_ZA
dc.subjectPlantsen_ZA
dc.subjectNitrogen fixationen_ZA
dc.subjectEcosystemsen_ZA
dc.subjectCarbonen_ZA
dc.subjectPhotosynthesisen_ZA
dc.subjectEcologyen_ZA
dc.subjectTerrestrialen_ZA
dc.titleNamib Desert primary productivity is driven by cryptic microbial community N-fixationen_ZA
dc.typeArticleen_ZA

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