title: Namib Desert dune/interdune transects exhibit habitat-specific edaphic bacterial communities.
abstract: The sand dunes and inter-dune zones of the hyper-arid central Namib Desert represent heterogeneous soil habitats. As little is known about their indigenous edaphic bacterial communities, we aimed to evaluate their diversity and factors of assembly and hypothesized that soil physicochemistry gradients would strongly shape dune/interdune communities. We sampled a total of 125 samples from 5 parallel dune/interdune transects and characterized 21 physico-chemical edaphic parameters coupled with 16S rRNA gene bacterial community fingerprinting using T-RFLP and 454 pyrosequencing. Multivariate analyses of T-RFLP data showed significantly different bacterial communities, related to physico-chemical gradients, in four distinct dune habitats: the dune top, slope, base and interdune zones. Pyrosequencing of 16S rRNA gene amplicon sets showed that each dune zone presented a unique phylogenetic profile, suggesting a high degree of environmental selection. The combined results strongly infer that habitat filtering is an important factor shaping Namib Desert dune bacterial communities, with habitat stability, soil texture and mineral and nutrient contents being the main environmental drivers of bacterial community structures.
authors.affiliation: Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria Pretoria, South Africa.
authors.forename: Sandra
authors.initials: S
authors.lastname: Ronca
authors.affiliation: Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria Pretoria, South Africa.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Ramond
authors.affiliation: Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria Pretoria, South Africa ; DuPont Industrial Biosciences Leiden, Netherlands.
authors.forename: Brian E
authors.initials: BE
authors.lastname: Jones
authors.affiliation: Gobabeb Research and Training Centre Walvis Bay, Namibia ; School of Animal, Plant and Environmental Sciences, University of the Witwatersrand Johannesburg, South Africa.
authors.forename: Mary
authors.initials: M
authors.lastname: Seely
authors.affiliation: Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria Pretoria, South Africa.
authors.forename: Don A
authors.initials: DA
authors.lastname: Cowan
keywords: arid ecosystems; deterministic assembly; dune transects; environmental gradient; habitat filtration; open soil