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Dryland biological soil crust cyanobacteria show unexpected decreases in abundance under long-term elevated CO2

January 1, 2013

Biological soil crusts (biocrusts) cover soil surfaces in many drylands globally. The impacts of 10 years of elevated atmospheric CO2 on the cyanobacteria in biocrusts of an arid shrubland were examined at a large manipulated experiment in Nevada, USA. Cyanobacteria-specific quantitative PCR surveys of cyanobacteria small-subunit (SSU) rRNA genes suggested a reduction in biocrust cyanobacterial biomass in the elevated CO2 treatment relative to the ambient controls. Additionally, SSU rRNA gene libraries and shotgun metagenomes showed reduced representation of cyanobacteria in the total microbial community. Taxonomic composition of the cyanobacteria was similar under ambient and elevated CO2 conditions, indicating the decline was manifest across multiple cyanobacterial lineages. Recruitment of cyanobacteria sequences from replicate shotgun metagenomes to cyanobacterial genomes representing major biocrust orders also suggested decreased abundance of cyanobacteria sequences across the majority of genomes tested. Functional assignment of cyanobacteria-related shotgun metagenome sequences indicated that four subsystem categories, three related to oxidative stress, were differentially abundant in relation to the elevated CO2 treatment. Taken together, these results suggest that elevated CO2 affected a generalized decrease in cyanobacteria in the biocrusts and may have favoured cyanobacteria with altered gene inventories for coping with oxidative stress.

Citation Information

Publication Year 2012
Title Dryland biological soil crust cyanobacteria show unexpected decreases in abundance under long-term elevated CO<sub>2</sub>
DOI 10.1111/1462-2920.12011
Authors Blaire Steven, La Verne Gallegos-Graves, Chris M. Yeager, Jayne Belnap, R. David Evans, Cheryl R. Kuske
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Microbiology
Series Number
Index ID 70107101
Record Source USGS Publications Warehouse
USGS Organization Southwest Biological Science Center