AUTHOR=Mogul Rakesh , Vaishampayan Parag , Bashir Mina , McKay Chris P. , Schubert Keith , Bornaccorsi Rosalba , Gomez Ernesto , Tharayil Sneha , Payton Geoffrey , Capra Juliana , Andaya Jessica , Bacon Leonard , Bargoma Emily , Black David , Boos Katie , Brant Michaela , Chabot Michael , Chau Danny , Cisneros Jessica , Chu Geoff , Curnutt Jane , DiMizio Jessica , Engelbrecht Christian , Gott Caroline , Harnoto Raechel , Hovanesian Ruben , Johnson Shane , Lavergne Britne , Martinez Gabriel , Mans Paul , Morales Ernesto , Oei Alex , Peplow Gary , Piaget Ryan , Ponce Nicole , Renteria Eduardo , Rodriguez Veronica , Rodriguez Joseph , Santander Monica , Sarmiento Khamille , Scheppelmann Allison , Schroter Gavin , Sexton Devan , Stephenson Jenin , Symer Kristin , Russo-Tait Tatiane , Weigel Bill , Wilhelm Mary B. TITLE=Microbial Community and Biochemical Dynamics of Biological Soil Crusts across a Gradient of Surface Coverage in the Central Mojave Desert JOURNAL=Frontiers in Microbiology VOLUME=8 YEAR=2017 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01974 DOI=10.3389/fmicb.2017.01974 ISSN=1664-302X ABSTRACT=

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.