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

Abstract Carbon 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 av...

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Autores principales:	Jean-Baptiste Ramond, Stephan Woodborne, Grant Hall, Mary Seely, Don A. Cowan
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2018
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/20ba7ddacc0d4eb5afdefd7c70bd76bf
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spelling	oai:doaj.org-article:20ba7ddacc0d4eb5afdefd7c70bd76bf2021-12-02T11:41:04ZNamib Desert primary productivity is driven by cryptic microbial community N-fixation10.1038/s41598-018-25078-42045-2322https://doaj.org/article/20ba7ddacc0d4eb5afdefd7c70bd76bf2018-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-25078-4https://doaj.org/toc/2045-2322Abstract Carbon 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 (δ 15N) 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 δ 15N values than soil organic matter. The δ 15N 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.Jean-Baptiste RamondStephan WoodborneGrant HallMary SeelyDon A. CowanNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-9 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Jean-Baptiste Ramond Stephan Woodborne Grant Hall Mary Seely Don A. Cowan Namib Desert primary productivity is driven by cryptic microbial community N-fixation
description	Abstract Carbon 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 (δ 15N) 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 δ 15N values than soil organic matter. The δ 15N 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.
format	article
author	Jean-Baptiste Ramond Stephan Woodborne Grant Hall Mary Seely Don A. Cowan
author_facet	Jean-Baptiste Ramond Stephan Woodborne Grant Hall Mary Seely Don A. Cowan
author_sort	Jean-Baptiste Ramond
title	Namib Desert primary productivity is driven by cryptic microbial community N-fixation
title_short	Namib Desert primary productivity is driven by cryptic microbial community N-fixation
title_full	Namib Desert primary productivity is driven by cryptic microbial community N-fixation
title_fullStr	Namib Desert primary productivity is driven by cryptic microbial community N-fixation
title_full_unstemmed	Namib Desert primary productivity is driven by cryptic microbial community N-fixation
title_sort	namib desert primary productivity is driven by cryptic microbial community n-fixation
publisher	Nature Portfolio
publishDate	2018
url	https://doaj.org/article/20ba7ddacc0d4eb5afdefd7c70bd76bf
work_keys_str_mv	AT jeanbaptisteramond namibdesertprimaryproductivityisdrivenbycrypticmicrobialcommunitynfixation AT stephanwoodborne namibdesertprimaryproductivityisdrivenbycrypticmicrobialcommunitynfixation AT granthall namibdesertprimaryproductivityisdrivenbycrypticmicrobialcommunitynfixation AT maryseely namibdesertprimaryproductivityisdrivenbycrypticmicrobialcommunitynfixation AT donacowan namibdesertprimaryproductivityisdrivenbycrypticmicrobialcommunitynfixation
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Namib Desert primary productivity is driven by cryptic microbial community N-fixation

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