Effects of burning on vegetation, soil physicochemistry and prokaryotic microbial communities in surface and subsurface peat.

Prescribed burning is a common management strategy in peatlands that has the potential to affect soil physicochemistry, alter biogeochemical cycles and trigger changes in vegetation structure. How burning affects prokaryotic community composition across different soil profiles is not well understood. This study explored the effects of prescribed burning on the diversity of prokaryotic communities in peat soils.

Spatial organisation of fungi in soil biocrusts of the Kalahari is related to bacterial community structure and may indicate ecological functions of fungi in drylands.

Biological soil crusts, or biocrusts, are microbial communities found in soil surfaces in drylands and in other locations where vascular plant cover is incomplete. They are functionally significant for numerous ecosystem services, most notably in the C fixation and storage due to the ubiquity of photosynthetic microbes. Whereas carbon fixation and storage have been well studied in biocrusts, the composition, function and characteristics of other organisms in the biocrust such as heterotrophic bacteria and especially fungi are considerably less studied and this limits our ability to gain a holistic understanding of biocrust ecology and function.

Effects of vegetation on bacterial communities, carbon and nitrogen in dryland soil surfaces: implications for shrub encroachment in the southwest Kalahari.

Shrub encroachment is occurring in many of the world's drylands, but its impacts on ecosystem structure and function are still poorly understood. In particular, it remains unclear how shrub encroachment affects dryland soil surfaces, including biological soil crust (biocrust) communities. In this study, soil surfaces (0-1 cm depth) were sampled from areas of Grewia flava shrubs and Eragrostis lehmanniana and Schmidtia kalahariensis grasses in the southwest Kalahari during two different seasons (March and November).

Detecting macroecological patterns in bacterial communities across independent studies of global soils.

The emergence of high-throughput DNA sequencing methods provides unprecedented opportunities to further unravel bacterial biodiversity and its worldwide role from human health to ecosystem functioning. However, despite the abundance of sequencing studies, combining data from multiple individual studies to address macroecological questions of bacterial diversity remains methodically challenging and plagued with biases. Here, using a machine-learning approach that accounts for differences among studies and complex interactions among taxa, we merge 30 independent bacterial data sets comprising 1,998 soil samples from 21 countries.

Bacterial and fungal communities in a degraded ombrotrophic peatland undergoing natural and managed re-vegetation.

The UK hosts 15-19% of global upland ombrotrophic (rain fed) peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions.

Diversity of planktonic and attached bacterial communities in a phenol-contaminated sandstone aquifer.

Polluted aquifers contain indigenous microbial communities with the potential for in situ bioremediation. However, the effect of hydrogeochemical gradients on in situ microbial communities (especially at the plume fringe, where natural attenuation is higher) is still not clear. In this study, we used culture-independent techniques to investigate the diversity of in situ planktonic and attached bacterial communities in a phenol-contaminated sandstone aquifer.

Dynamic changes in microbial community structure and function in phenol-degrading microcosms inoculated with cells from a contaminated aquifer.

Contamination of aquifers by organic pollutants threatens groundwater supplies and the environment. In situ biodegradation of organic pollutants by microbial communities is important for the remediation of contaminated sites, but our understanding of the relationship between microbial development and pollutant biodegradation is poor. A particular challenge is understanding the in situ status of microorganisms attached to solid surfaces, but not accessible via conventional sampling of groundwater.

The polymer physics and chemistry of microbial cell attachment and adhesion.

The attachment of microbial cells to solid substrata is a primary ecological strategy for the survival of species and the development of specific activity and function within communities. An hypothesis arising from a biological sciences perspective may be stated as follows: The attachment of microbes to interfaces is controlled by the macromolecular structure of the cell wall and the functional genes that are induced for its biological synthesis. Following logically from this is the view that diverse attached cell behaviour is mediated by the physical and chemical interactions of these macromolecules in the interfacial region and with other cells.

Aggregative behavior of bacteria isolated from canine dental plaque.

Interbacterial adhesion of bacteria isolated from canine dental plaque was assessed by performing a visual coaggregation assay. Using conditions mimicking those likely to be encountered in vivo, the entire cultivable plaque microbiota from a single dog was assessed, and eight (6.7%) unique coaggregation interactions were detected for 120 crosses.

Cultivable oral microbiota of domestic dogs.

Bacteria were isolated from the dental plaques of nine dogs and a sample of pooled saliva from five other dogs and were then identified by comparative 16S rRNA gene sequencing. Among 339 isolates, 84 different phylotypes belonging to 37 genera were identified. Approximately half of the phylotypes were identified to the species level, and 28% of these were considered members of the indigenous oral microbiota of humans.