Ignimbrite textural properties as determinants of endolithic colonization patterns from hyper-arid Atacama Desert


  • Beatriz Cámara National Museum of Natural Sciences-CSIC, Madrid.
  • Shino Suzuki J. Craig Venter Institute, La Jolla, CA.
  • Kenneth H Nealson 1. J. Craig Venter Institute, La Jolla, CA. 2. University of Southern California, Los Angeles, CA.
  • Jacek Wierzchos National Museum of Natural Sciences-CSIC, Madrid.
  • Carmen Ascaso National Museum of Natural Sciences-CSIC, Madrid.
  • Octavio Artieda Department of Plant Biology, Ecology and Earth Sciences. University of Extremadura, Plasencia.
  • Asunción de los Ríos National Museum of Natural Sciences-CSIC, Madrid, Spain.


Chroococcidiopsis sp., endoliths, ignimbrite, rock porosity, volcanic rock, Atacama Desert


This study explores the photosynthetic microbial colonization of rhyolitic ignimbrites in Lomas de Tilocalar, a hyper-arid region of the Atacama Desert, Chile. Colonization appeared in the form of a green layer a few millimeters beneath the ignimbrite surface. Some ignimbrite rocks revealed two distinct micromorphological areas of identical mineralogical and chemical composition but different textural properties. According to texture, colonization patterns varied in terms of the extension and depth of colonization. The diversity of photosynthetic microorganisms was assessed by denaturing gradient gel electrophoresis (DGGE) of the 23S rRNA gene and by generating clone libraries of the 16S rRNA gene. We observed a low diversity of  photosynthetic microorganisms colonizing the ignimbrite microhabitat. Most rRNA gene sequences recovered greatly resembled those of  Chroococcidiopsis hypolith clones from arid deserts. These results point to highly restrictive conditions of the hyper-arid Atacama Desert conditioning the diversity of cyanobacteria, and suggest that microbial colonization and composition patterns might be determined by the microscale physico-chemical properties of the ignimbrite rocks. [Int Microbiol 2014; 17(4):235-247]

Keywords: Chroococcidiopsis sp. · endoliths · ignimbrite · rock porosity · volcanic rock · Atacama Desert

Author Biography

Beatriz Cámara, National Museum of Natural Sciences-CSIC, Madrid.




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