Novel lichen-dominated hypolithic communities in the Namib Desert

• Asunción de los Ríos ^[1] ; Isaac Garrido-Benavent ^{[1] [5]} ; Alicia Limón ^[1] ; Errol D. Cason ^[2] ; Gillian Maggs-Kölling ^[6] ; Don Cowan ^[3] ; Angel Valverde ^[4]
  1. [1] Museo Nacional de Ciencias Naturales

     Museo Nacional de Ciencias Naturales

     Madrid, España

     
  2. [2] University of the Free State

     University of the Free State

     Mangaung, Sudáfrica

     
  3. [3] University of Pretoria

     University of Pretoria

     City of Tshwane, Sudáfrica

     
  4. [4] Instituto de Recursos Naturales y Agrobiología de Salamanca

     Instituto de Recursos Naturales y Agrobiología de Salamanca

     Salamanca, España

     
  5. [5] Universitat de València

     Universitat de València

     Valencia, España

     
  6. [6] Gobabeb-Namib Research Institute, Walvis Bay, Namibia

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• Localización: Microbial ecology, ISSN-e 1432-184X, ISSN 0095-3628, Vol. 83, Nº. 4, 2022, págs. 1036-1048
• Idioma: inglés
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• Resumen

  • The ventral surfaces of translucent rocks from hot desert pavements often harbor hypolithic microbial communities, which are mostly dominated by cyanobacteria. The Namib Desert fog belt supports extensive hypolithic colonization of quartz rocks, which are also colonized by lichens on their dorsal surfaces. Here, we aim to evaluate whether lichens colonize the ventral surface of the rocks (i.e., show hypolithic lifestyle) and compare the bacterial composition of these coastal hypolithic communities with those found inland. Fungal DNA barcoding and fungal and bacterial Illumina metabarcoding were combined with electron microscopy to characterize the composition and spatial structure of hypolithic communities from two (coastal and inland) areas in the Namib Desert. We report, for the first time, the structure and composition of lichen-dominated hypolithic communities found in the coastal zone of the Namib Desert with extensive epilithic lichen cover. Lichen modified areoles with inverted morphology of the genus Stellarangia (three lineages) and Buellia (two lineages) were the main components of these hypolithic communities. Some of these lineages were also found in epilithic habitats. These lichen-dominated hypolithic communities differed in structural organization and bacterial community composition from those found in inland areas. The hypolithic lichen colonization characterized here seems not to be an extension of epilithic or biological soil crust lichen growths but the result of specific sublithic microenvironmental conditions. Moisture derived from fog and dew could be the main driver of this unique colonization.