Frontiers in Microbiology (Oct 2017)

Microbial Community and Biochemical Dynamics of Biological Soil Crusts across a Gradient of Surface Coverage in the Central Mojave Desert

  • Rakesh Mogul,
  • Rakesh Mogul,
  • Parag Vaishampayan,
  • Parag Vaishampayan,
  • Parag Vaishampayan,
  • Mina Bashir,
  • Mina Bashir,
  • Mina Bashir,
  • Chris P. McKay,
  • Chris P. McKay,
  • Keith Schubert,
  • Keith Schubert,
  • Rosalba Bornaccorsi,
  • Rosalba Bornaccorsi,
  • Ernesto Gomez,
  • Ernesto Gomez,
  • Sneha Tharayil,
  • Sneha Tharayil,
  • Geoffrey Payton,
  • Geoffrey Payton,
  • Juliana Capra,
  • Juliana Capra,
  • Jessica Andaya,
  • Jessica Andaya,
  • Leonard Bacon,
  • Leonard Bacon,
  • Emily Bargoma,
  • Emily Bargoma,
  • David Black,
  • David Black,
  • Katie Boos,
  • Katie Boos,
  • Michaela Brant,
  • Michaela Brant,
  • Michael Chabot,
  • Michael Chabot,
  • Danny Chau,
  • Danny Chau,
  • Jessica Cisneros,
  • Jessica Cisneros,
  • Geoff Chu,
  • Geoff Chu,
  • Jane Curnutt,
  • Jane Curnutt,
  • Jessica DiMizio,
  • Jessica DiMizio,
  • Christian Engelbrecht,
  • Christian Engelbrecht,
  • Caroline Gott,
  • Caroline Gott,
  • Raechel Harnoto,
  • Raechel Harnoto,
  • Ruben Hovanesian,
  • Ruben Hovanesian,
  • Shane Johnson,
  • Shane Johnson,
  • Britne Lavergne,
  • Britne Lavergne,
  • Gabriel Martinez,
  • Gabriel Martinez,
  • Paul Mans,
  • Paul Mans,
  • Ernesto Morales,
  • Ernesto Morales,
  • Alex Oei,
  • Alex Oei,
  • Gary Peplow,
  • Gary Peplow,
  • Ryan Piaget,
  • Ryan Piaget,
  • Nicole Ponce,
  • Nicole Ponce,
  • Eduardo Renteria,
  • Eduardo Renteria,
  • Veronica Rodriguez,
  • Veronica Rodriguez,
  • Joseph Rodriguez,
  • Joseph Rodriguez,
  • Monica Santander,
  • Monica Santander,
  • Khamille Sarmiento,
  • Khamille Sarmiento,
  • Allison Scheppelmann,
  • Allison Scheppelmann,
  • Gavin Schroter,
  • Gavin Schroter,
  • Devan Sexton,
  • Devan Sexton,
  • Jenin Stephenson,
  • Jenin Stephenson,
  • Kristin Symer,
  • Kristin Symer,
  • Tatiane Russo-Tait,
  • Tatiane Russo-Tait,
  • Bill Weigel,
  • Bill Weigel,
  • Mary B. Wilhelm,
  • Mary B. Wilhelm

DOI
https://doi.org/10.3389/fmicb.2017.01974
Journal volume & issue
Vol. 8

Abstract

Read online

In this study, we expand upon the biogeography of biological soil crusts (BSCs) and provide molecular insights into the microbial community and biochemical dynamics along the vertical BSC column structure, and across a transect of increasing BSC surface coverage in the central Mojave Desert, CA, United States. Next generation sequencing reveals a bacterial community profile that is distinct among BSCs in the southwestern United States. Distribution of major phyla in the BSC topsoils included Cyanobacteria (33 ± 8%), Proteobacteria (26 ± 6%), and Chloroflexi (12 ± 4%), with Phormidium being the numerically dominant genus. Furthermore, BSC subsurfaces contained Proteobacteria (23 ± 5%), Actinobacteria (20 ± 5%), and Chloroflexi (18 ± 3%), with an unidentified genus from Chloroflexi (AKIW781, order) being numerically dominant. Across the transect, changes in distribution at the phylum (p < 0.0439) and genus (p < 0.006) levels, including multiple biochemical and geochemical trends (p < 0.05), positively correlated with increasing BSC surface coverage. This included increases in (a) Chloroflexi abundance, (b) abundance and diversity of Cyanobacteria, (b) OTU-level diversity in the topsoil, (c) OTU-level differentiation between the topsoil and subsurface, (d) intracellular ATP abundances and catalase activities, and (e) enrichments in clay, silt, and varying elements, including S, Mn, Co, As, and Pb, in the BSC topsoils. In sum, these studies suggest that BSCs from regions of differing surface coverage represent early successional stages, which exhibit increasing bacterial diversity, metabolic activities, and capacity to restructure the soil. Further, these trends suggest that BSC successional maturation and colonization across the transect are inhibited by metals/metalloids such as B, Ca, Ti, Mn, Co, Ni, Mo, and Pb.

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