title: Microbial hitchhikers on intercontinental dust: catching a lift in Chad.
abstract: Ancient mariners knew that dust whipped up from deserts by strong winds travelled long distances, including over oceans. Satellite remote sensing revealed major dust sources across the Sahara. Indeed, the Bodélé Depression in the Republic of Chad has been called the dustiest place on earth. We analysed desert sand from various locations in Chad and dust that had blown to the Cape Verde Islands. High throughput sequencing techniques combined with classical microbiological methods showed that the samples contained a large variety of microbes well adapted to the harsh desert conditions. The most abundant bacterial groupings in four different phyla included: (a) Firmicutes-Bacillaceae, (b) Actinobacteria-Geodermatophilaceae, Nocardiodaceae and Solirubrobacteraceae, (c) Proteobacteria-Oxalobacteraceae, Rhizobiales and Sphingomonadaceae, and (d) Bacteroidetes-Cytophagaceae. Ascomycota was the overwhelmingly dominant fungal group followed by Basidiomycota and traces of Chytridiomycota, Microsporidia and Glomeromycota. Two freshwater algae (Trebouxiophyceae) were isolated. Most predominant taxa are widely distributed land inhabitants that are common in soil and on the surfaces of plants. Examples include Bradyrhizobium spp. that nodulate and fix nitrogen in Acacia species, the predominant trees of the Sahara as well as Herbaspirillum (Oxalobacteraceae), a group of chemoorganotrophic free-living soil inhabitants that fix nitrogen in association with Gramineae roots. Few pathogenic strains were found, suggesting that African dust is not a large threat to public health.
authors.affiliation: Université de Genève, Sciences III, Genève 4, Switzerland.
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Favet
authors.forename: Ales
authors.initials: A
authors.lastname: Lapanje
authors.forename: Adriana
authors.initials: A
authors.lastname: Giongo
authors.forename: Suzanne
authors.initials: S
authors.lastname: Kennedy
authors.forename: Yin-Yin
authors.initials: YY
authors.lastname: Aung
authors.forename: Arlette
authors.initials: A
authors.lastname: Cattaneo
authors.forename: Austin G
authors.initials: AG
authors.lastname: Davis-Richardson
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Brown
authors.forename: Renate
authors.initials: R
authors.lastname: Kort
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Brumsack
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schnetger
authors.forename: Adrian
authors.initials: A
authors.lastname: Chappell
authors.forename: Jaap
authors.initials: J
authors.lastname: Kroijenga
authors.forename: Andreas
authors.initials: A
authors.lastname: Beck
authors.forename: Karin
authors.initials: K
authors.lastname: Schwibbert
authors.forename: Ahmed H
authors.initials: AH
authors.lastname: Mohamed
authors.forename: Timothy
authors.initials: T
authors.lastname: Kirchner
authors.forename: Patricia Dorr
authors.initials: PD
authors.lastname: de Quadros
authors.forename: Eric W
authors.initials: EW
authors.lastname: Triplett
authors.forename: William J
authors.initials: WJ
authors.lastname: Broughton
authors.forename: Anna A
authors.initials: AA
authors.lastname: Gorbushina
mesh_terms: D000352:Africa, Northern; D000391:Air Microbiology; D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification*; D055726:Cabo Verde; D002596:Chad; D003889:Desert Climate; D004391:Dust / Q000032:analysis; D005658:Fungi / Q000145:classification* / Q000302:isolation & purification; D012987:Soil / Q000032:analysis; D014919:Wind
chemical_list: D004391:Dust; D012987:Soil