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R. David Evans

Elevated anthropogenic nitrogen (N) emissions are causing higher rates of atmospheric N deposition (Ndep) that may saturate Cascade ecosystems with reactive N. Simultaneously, increasing global temperatures and altered circulation patterns generated by climate change are expected to strongly impact snow regimes in the Cascade Range, causing reduced snowpack, earlier snowmelt dates, and higher proportions of rain precipitation. Concern over the impacts of Ndep to sensitive, high-elevation ecosystems has prompted calls for research into its interaction with climate change and the effects of Ndep on ecosystem services. This is a collaborative project between the National Park Service and Washington State University...
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...
Categories: Publication; Types: Citation; Tags: Environmental Microbiology
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