Learn More
Introduction Global change caused by anthropogenic activities may significantly modify the abundance, structure, and function of biological soil crusts. The components of global change can be grouped into (1) those that impact discreet sites but are occurring on a global scale, such as land-use change and invasive species, and (2) those that alter(More)
We characterized, at millimeter resolution, bacterial biomass, diversity, and vertical stratification of biological soil crusts in arid lands from the Colorado Plateau. Microscopic counts, extractable DNA, and plate counts of viable aerobic copiotrophs (VAC) revealed that the top centimeter of crusted soils contained atypically large bacterial populations,(More)
We compared the community structures of cyanobacteria in four biological desert crusts from Utah's Colorado Plateau developing on different substrata. We analyzed natural samples, cultures, and cyanobacterial filaments or colonies retrieved by micromanipulation from field samples using microscopy, denaturing gradient gel electrophoresis, and sequencing of(More)
We quantified the diversity of oxygenic phototrophic microorganisms present in eight hypersaline microbial mats on the basis of three cultivation-independent approaches. Morphological diversity was studied by microscopy. The diversity of carotenoids was examined by extraction from mat samples and high-pressure liquid chromatography analysis. The diversity(More)
Exposure to the shortest wavelengths in sunlight, ultraviolet light, constitutes a deleterious ecological factor for many microorganisms. The use of secondary metabolites as sunscreens has emerged as an important photoprotective mechanism in certain groups of large-celled microorganisms, such as cyanobacteria, fungi and many protists. In this Review, we(More)
The proposed photoprotective role of the UV-A absorbing, extracellular pigment scytonemin was studied in the terrestrial cyanobacterium Chlorogloeopsis sp. strain O-89-Cgs(1). UV-A (315-400 nm) caused growth delay, cell growth restarting only when scytonemin had accumulated in the extracellular envelopes. Cultures with scytonemin were more resistant to(More)
We developed and tested a set of oligonucleotide primers for the specific amplification of 16S rRNA gene segments from cyanobacteria and plastids by PCR. PCR products were recovered from all cultures of cyanobacteria and diatoms that were checked but not from other bacteria and archaea. Gene segments selectively retrieved from cyanobacteria and diatoms in(More)
Strain CP2CT was isolated from biological soil crusts in the Colorado Plateau, USA. The isolate was aerobic, facultatively fermentative, Gram-negative, non-motile and red-pigmented (due to the presence of carotenoids), but did not contain bacteriochlorophyll a. The strain tested positive for catalase, oxidase and urease and was negative for lysine and(More)
We studied the bacterial communities in biological soil crusts (BSCs) from the Colorado Plateau by enrichment and cultivation, and by statistically analyzed denaturing gradient gel electrophoresis (DGGE) fingerprinting of environmental 16S rRNA genes, and phylogenetic analyses. Three 500-m-long transects, tens of km apart, consisting of 10 equally spaced(More)