scholarly journals Diazotrophic Community Structure and Function in Two Successional Stages of Biological Soil Crusts from the Colorado Plateau and Chihuahuan Desert

2004 ◽  
Vol 70 (2) ◽  
pp. 973-983 ◽  
Author(s):  
Chris M. Yeager ◽  
Jennifer L. Kornosky ◽  
David C. Housman ◽  
Edmund E. Grote ◽  
Jayne Belnap ◽  
...  
Keyword(s):  
Community Structure ◽  
Chihuahuan Desert ◽  
Nitrogenase Activity ◽  
Colorado Plateau ◽  
Biological Soil Crusts ◽  
Rrna Gene ◽  
Soil Crusts ◽  
Clone Sequencing ◽  
Microcoleus Vaginatus ◽  
Diazotrophic Community

ABSTRACT The objective of this study was to characterize the community structure and activity of N2-fixing microorganisms in mature and poorly developed biological soil crusts from both the Colorado Plateau and Chihuahuan Desert. Nitrogenase activity was approximately 10 and 2.5 times higher in mature crusts than in poorly developed crusts at the Colorado Plateau site and Chihuahuan Desert site, respectively. Analysis of nifH sequences by clone sequencing and the terminal restriction fragment length polymorphism technique indicated that the crust diazotrophic community was 80 to 90% heterocystous cyanobacteria most closely related to Nostoc spp. and that the composition of N2-fixing species did not vary significantly between the poorly developed and mature crusts at either site. In contrast, the abundance of nifH sequences was approximately 7.5 times greater (per microgram of total DNA) in mature crusts than in poorly developed crusts at a given site as measured by quantitative PCR. 16S rRNA gene clone sequencing and microscopic analysis of the cyanobacterial community within both crust types demonstrated a transition from a Microcoleus vaginatus-dominated, poorly developed crust to mature crusts harboring a greater percentage of Nostoc and Scytonema spp. We hypothesize that ecological factors, such as soil instability and water stress, may constrain the growth of N2-fixing microorganisms at our study sites and that the transition to a mature, nitrogen-producing crust initially requires bioengineering of the surface microenvironment by Microcoleus vaginatus.

scholarly journals Sphingomonas mucosissima sp. nov. and Sphingomonas desiccabilis sp. nov., from biological soil crusts in the Colorado Plateau, USA

2007 ◽  
Vol 57 (5) ◽  
pp. 1028-1034 ◽  
Author(s):  
G. S. N. Reddy ◽  
Ferran Garcia-Pichel
Keyword(s):  
Type Strain ◽  
Gene Sequence ◽  
Novel Species ◽  
Colorado Plateau ◽  
Sequence Similarity ◽  
Biological Soil Crusts ◽  
Phenotypic Characterization ◽  
Rrna Gene ◽  
Dna Relatedness ◽  
Soil Crusts

Two bacterial strains, CP173-2T and CP1DT, were isolated from biological soil crusts (BSCs) collected in the Colorado Plateau, USA. Both strains were pigmented, Gram-negative, non-motile rods and produced abundant mucus. They contained C16 : 0, C18 : 1 ω7c and C14 : 0 2-OH as the predominant cellular fatty acids, ubiquinone-10 as the isoprenoid quinone and sphingoglycolipid. Based on the above characteristics, the isolates were assigned to the family Sphingomonadaceae; 16 rRNA gene signature nucleotides placed them within the genus Sphingomonas. Strains CP173-2T and CP1DT had a 16S rRNA gene sequence similarity of 96.7 % with each other and 91.6–98.9 % sequence similarity with other species in the genus, indicating that they represent two separate, and possibly novel, species. The closest species to strains CP173-2T and CP1DT were, respectively, Sphingomonas dokdonensis (98.9 % gene sequence similarity) and Sphingomonas panni (97.9 %). However, strain CP173-2T exhibited a DNA–DNA relatedness of only 32.5 % with the type strain of S. dokdonensis. Similarly, the DNA–DNA relatedness between strain CP1DT and the type strain of S. panni was only 18 %. Phenotypic characterization supported this low relatedness. On the basis of this evidence, we propose that the new strains represent two novel species, for which the names Sphingomonas mucosissima sp. nov. (with type strain CP173-2T=ATCC BAA-1239T=DSM 17494T) and Sphingomonas desiccabilis sp. nov. (with type strain CP1DT=ATCC BAA-1041T=DSM 16792T) are proposed.

Species-specific nitrogenase activity in lichen-dominated biological soil crusts from the Colorado Plateau, USA

2018 ◽  
Vol 429 (1-2) ◽  
pp. 113-125 ◽  
Author(s):  
Terry J. Torres-Cruz ◽  
Armin J. Howell ◽  
Robin H. Reibold ◽  
Theresa A. McHugh ◽  
Mackenzie A. Eickhoff ◽  
...  
Keyword(s):  
Nitrogenase Activity ◽  
Colorado Plateau ◽  
Biological Soil Crusts ◽  
Soil Crusts ◽  
Species Specific

scholarly journals Dyadobacter crusticola sp. nov., from biological soil crusts in the Colorado Plateau, USA, and an emended description of the genus Dyadobacter Chelius and Triplett 2000

2005 ◽  
Vol 55 (3) ◽  
pp. 1295-1299 ◽  
Author(s):  
Gundlapally S. N. Reddy ◽  
Ferran Garcia-Pichel
Keyword(s):  
Type Strain ◽  
Colorado Plateau ◽  
Sequence Similarity ◽  
Stationary Growth Phase ◽  
Biological Soil Crusts ◽  
Rrna Gene ◽  
Stationary Growth ◽  
Soil Crusts ◽  
Gene Sequence Analysis ◽  
Emended Description

Bacterial strain CP183-8T was isolated from biological soil crusts collected in the Colorado Plateau, USA. Cells of this strain were aerobic, non-motile, Gram-negative, psychrotolerant and formed beaded chains in the stationary growth phase. They contained C16 : 1 ω5c and C16 : 1 ω7c as major fatty acids. 16S rRNA gene sequence analysis assigned the strain to the genus Dyadobacter. However, it shared a sequence similarity of only 95·88 % with the type strain of Dyadobacter fermentans, NS114T. Because it also exhibited a significant number of phenotypic and chemotaxonomic differences from D. fermentans, it is described as a novel second species in the genus Dyadobacter, with the name Dyadobacter crusticola sp. nov. The type strain is CP183-8T (=DSM 16708T=ATCC BAA-1036T).

Exposure to predicted precipitation patterns decreases population size and alters community structure of cyanobacteria in biological soil crusts from the Chihuahuan Desert

2017 ◽  
Vol 20 (1) ◽  
pp. 259-269 ◽  
Author(s):  
Vanessa M.C. Fernandes ◽  
Náthali Maria Machado de Lima ◽  
Daniel Roush ◽  
Jennifer Rudgers ◽  
Scott L. Collins ◽  
...  
Keyword(s):  
Community Structure ◽  
Population Size ◽  
Chihuahuan Desert ◽  
Biological Soil Crusts ◽  
Precipitation Patterns ◽  
Soil Crusts

scholarly journals Climate change and physical disturbance cause similar community shifts in biological soil crusts

2015 ◽  
Vol 112 (39) ◽  
pp. 12116-12121 ◽  
Author(s):  
Scott Ferrenberg ◽  
Sasha C. Reed ◽  
Jayne Belnap
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Summer Rainfall ◽  
Community Change ◽  
Biological Soil Crusts ◽  
Physical Disturbance ◽  
Precipitation Frequency ◽  
Soil Crusts ◽  
Altered Precipitation

Biological soil crusts (biocrusts)—communities of mosses, lichens, cyanobacteria, and heterotrophs living at the soil surface—are fundamental components of drylands worldwide, and destruction of biocrusts dramatically alters biogeochemical processes, hydrology, surface energy balance, and vegetation cover. Although there has been long-standing concern over impacts of physical disturbances on biocrusts (e.g., trampling by livestock, damage from vehicles), there is increasing concern over the potential for climate change to alter biocrust community structure. Using long-term data from the Colorado Plateau, we examined the effects of 10 y of experimental warming and altered precipitation (in full-factorial design) on biocrust communities and compared the effects of altered climate with those of long-term physical disturbance (>10 y of replicated human trampling). Surprisingly, altered climate and physical disturbance treatments had similar effects on biocrust community structure. Warming, altered precipitation frequency [an increase of small (1.2 mm) summer rainfall events], and physical disturbance from trampling all promoted early successional community states marked by dramatic declines in moss cover and increases in cyanobacteria cover, with more variable effects on lichens. Although the pace of community change varied significantly among treatments, our results suggest that multiple aspects of climate change will affect biocrusts to the same degree as physical disturbance. This is particularly disconcerting in the context of warming, as temperatures for drylands are projected to increase beyond those imposed as treatments in our study.

Biological soil crusts: new genera and species of Cyanobacteria from Brazilian semi-arid regions

Phytotaxa ◽  
2020 ◽  
Vol 470 (4) ◽  
pp. 263-281
Author(s):  
NÁTHALI MARIA MACHADO DE LIMA ◽  
LUIS H.Z. BRANCO
Keyword(s):  
Carbon Fixation ◽  
Phylogenetic Analyses ◽  
Close Relation ◽  
Biological Soil Crusts ◽  
Rrna Gene ◽  
New Genera ◽  
Filamentous Cyanobacteria ◽  
Soil Crusts ◽  
Code Of Nomenclature ◽  
Real Composition

In the uppermost millimeters of soils is commonly found a thin layer of cryptobiotic organisms, including cyanobacteria, microalgae, lichens, mosses, fungi, bacteria and archaea. These communities are called Biological Soil Crusts (BSCs) or biocrusts and perform important ecological functions, mainly attributed to their capacity of providing soil stability and incorporate nutrients through nitrogen and carbon fixation. Among all the organisms found in the biocrusts, the filamentous cyanobacteria Microcoleus vaginatus and M. steenstrupii are the best studied soil colonizers. The genus Microcoleus is considered complex and has been showing close relation with some species of Phormidium. The poor understanding about these two genera is a limit to the description of the real composition of biocrusts and can generate underestimations in the diversity community and the use of wrong organisms in applied projects (e.g. environmental restoration). This work studied eight cyanobacterial populations from Brazilian BSCs sampled in the Caatinga biome. The populations presented Microcoleus-like and Phormidium-like morphologies, but the phylogenetic analyses based on 16S rRNA gene sequences showed that they represent three new genera and six new species of filamentous cyanobacteria associated to the cryptic genera, they are Pycnacronema caatingensis sp. nov., Pycnacronema edaphica sp. nov., Gracilinea arenicola gen. et sp. nov., Marmoreocelis xerophila gen. et sp. nov., Konicacronema caatinguensis gen. et sp. nov. and Trichocoleus caatingensis sp. nov. The generic name and specific epithets of the new taxa are proposed according to the provisions of the International Code of Nomenclature of algae, fungi, and plants.

Nitrogenase activity by biological soil crusts in cold sagebrush steppe ecosystems

2017 ◽  
Vol 134 (1-2) ◽  
pp. 57-76 ◽  
Author(s):  
Stacy G. Schwabedissen ◽  
Kathleen A. Lohse ◽  
Sasha C. Reed ◽  
Ken A. Aho ◽  
Timothy S. Magnuson
Keyword(s):  
Nitrogenase Activity ◽  
Biological Soil Crusts ◽  
Sagebrush Steppe ◽  
Soil Crusts ◽  
Steppe Ecosystems

scholarly journals Flux balance modeling to predict bacterial survival during pulsed-activity events

2018 ◽  
Vol 15 (7) ◽  
pp. 2219-2229 ◽  
Author(s):  
Nicholas A. Jose ◽  
Rebecca Lau ◽  
Tami L. Swenson ◽  
Niels Klitgord ◽  
Ferran Garcia-Pichel ◽  
...  
Keyword(s):  
Mass Spectroscopy ◽  
Compatible Solutes ◽  
Soil Microbial Communities ◽  
Metabolic Model ◽  
Biological Soil Crusts ◽  
Arid Environments ◽  
Bacterial Survival ◽  
Flux Balance ◽  
Soil Crusts ◽  
Microcoleus Vaginatus

Abstract. Desert biological soil crusts (BSCs) are cyanobacteria-dominated surface soil microbial communities common to plant interspaces in arid environments. The capability to significantly dampen their metabolism allows them to exist for extended periods in a desiccated dormant state that is highly robust to environmental stresses. However, within minutes of wetting, metabolic functions reboot, maximizing activity during infrequent permissive periods. Microcoleus vaginatus, a primary producer within the crust ecosystem and an early colonizer, initiates crust formation by binding particles in the upper layer of soil via exopolysaccharides, making microbial dominated biological soil crusts highly dependent on the viability of this organism. Previous studies have suggested that biopolymers play a central role in the survival of this organism by powering resuscitation, rapidly forming compatible solutes, and fueling metabolic activity in dark, hydrated conditions. To elucidate the mechanism of this phenomenon and provide a basis for future modeling of BSCs, we developed a manually curated, genome-scale metabolic model of Microcoleus vaginatus (iNJ1153). To validate this model, gas chromatography–mass spectroscopy (GC–MS) and liquid chromatography–mass spectroscopy (LC–MS) were used to characterize the rate of biopolymer accumulation and depletion in in hydrated Microcoleus vaginatus under light and dark conditions. Constraint-based flux balance analysis showed agreement between model predictions and experimental reaction fluxes. A significant amount of consumed carbon and light energy is invested into storage molecules glycogen and polyphosphate, while β-polyhydroxybutyrate may function as a secondary resource. Pseudo-steady-state modeling suggests that glycogen, the primary carbon source with the fastest depletion rate, will be exhausted if M. vaginatus experiences dark wetting events 4 times longer than light wetting events.

Sign in / Sign up

Export Citation Format

Share Document