Metagenomics and biodiversity of sphagnum bogs

Biodiversity of sphagnum bogs is one of the richest and less studied, while these ecosystems are among the top ones in ecological, conservation, and economic value. Recent studies focused on the prokaryotic consortia associated with sphagnum mosses, and revealed the factors that maintain sustainability and productivity of bog ecosystems. High-throughput sequencing technologies provided insight into functional diversity of moss microbial communities (microbiomes), and helped to identify the biochemical pathways and gene families that facilitate the spectrum of adaptive strategies and largely foster the very successful colonization of the Northern hemisphere by sphagnum mosses. Rich and valuable information obtained on microbiomes of peat bogs sets off the paucity of evidence on their eukaryotic diversity. Prospects and expectations of reliable assessment of taxonomic profiles, relative abundance of taxa, and hidden biodiversity of microscopic eukaryotes in sphagnum bog ecosystems are briefly outlined in the context of today’s metagenomics.     

Modern gas-exchange processes in forest-steppe sphagnum bogs in the Baraba (West Siberia)

Peculiarities of forming emission flows of carbon dioxide and methane in forest-steppe raised Sphagnum bogs have been studied in view of coenotic structure and damage to the vegetation as a result of fire. The reasons of relatively low rate of methane emission in pine-dwarf shrub Sphagnum bogs under the marginal conditions have been analyzed. The concentrations of CH₄ and CO₂ in bog waters have been presented.     

Antibacterial activity of sphagnum acid and other phenolic compounds found in Sphagnum papillosum against food-borne bacteria

Aims:  To identify the phenolic compounds in the leaves of Sphagnum papillosum and examine their antibacterial activity at pH appropriate for the undissociated forms.
Methods and Results:  Bacterial counts of overnight cultures showed that whilst growth of Staphylococcus aureus 50084 was impaired in the presence of milled leaves, the phenol-free fraction of holocellulose of S. papillosum had no bacteriostatic effect. Liquid chromatography–mass spectrometry analysis of an acetone–methanol extract of the leaves detected eight phenolic compounds. Antibacterial activity of the four dominating phenols specific to Sphagnum leaves, when assessed in vitro as minimal inhibitory concentrations (MICs), were generally >2·5 mg ml⁻¹. MIC values of the Sphagnum- specific compound 'sphagnum acid' [ p -hydroxy-β-(carboxymethyl)-cinnamic acid] were >5 mg ml⁻¹. No synergistic or antagonistic effects of the four dominating phenols were detected in plate assays.
Conclusions:  Sphagnum -derived phenolics exhibit antibacterial activity in vitro only at concentrations far in excess of those found in the leaves.
Significance and Impact of the Study:  We have both identified the phenolic compounds in S. papillosum and assessed their antibacterial activity. Our data indicate that phenolic compounds in isolation are not potent antibacterial agents and we question their potency against food-borne pathogens.     

Bacteria of the genus Burkholderia as a typical component of the microbial community of sphagnum peat bogs

Bacteria of the genus Burkholderia are a typical component of the microbial complex of sphagnum peat bogs and constitute a substantial portion of the aerobic chemoorganotrophic isolates which are routinely obtained from these environments on acidic nutrient media. The ecophysiological characteristics of the 27 strains of such organisms, which were isolated from the peat of acidic sphagnum bogs of the boreal and tundra zones of Russia, Canada, and Estonia, were investigated in the present paper. The overwhelming majority of the Burkholderia strains isolated from these bogs were phylogenetically close to the species B. glathei, B. phenazinium, B. fungorum, and B. caryophylli, the typical inhabitants of soil and plant rhizosphere. The bog isolates utilized a broad range of substrates as carbon and energy sources, including organic acids, sugars, polyalcohols, and certain aromatic compounds. All the strains studied were capable of growth on nitrogen-free media. They developed in the pH ranges of 3.5 to 7.4 and from 3 to 37 degrees C, with the optima at pH 5-7 and 11-23 degrees C, respectively. They were therefore moderately acidophilic, psychroactive, dinitrogen-fixing microorganisms well adapted to the conditions of acidic northern sphagnum bogs.     

The species composition and distribution of diatoms in sphagnum bogs of European Russia: Ecosystems of the Volga Upland

The species composition of diatoms in ten sphagnum bogs of the Volga Upland (Penzenskaya oblast) was studied. A systematic and ecologo-geographical analysis of flora was performed. A great number of algae were found (291 species and intraspecific taxon) that differ in specific ecological features and frequency of occurrence in samples. The horizontal heterogeneity of diatom communities in the sphagnum cover was established, and a decrease in the number of species from the center to the bog periphery was determined.     

The species composition and distribution of diatom algae in sphagnum bogs in European Russia: The Polistovo-Lovatskii land tract

The species composition of diatom algae in the Polistovo-Lovatskii sphagnum tract (Rdeiskoye bog, Novgorod oblast) \are studied. The systematic and ecological-geographical analyses of the flora are performed. A total of 256 species and intraspecific taxa differing in ecological specificities and frequencies of occurrence in samples are revealed. A considerable number of centric diatoms is found. It is shown that primary and secondary diatom communities are formed in large sphagnum tracts. The horizontal heterogeneity of diatom communities in sphagnum bog is revealed. The species diversities of diatom algae in different bogs are compared.     

Wisconsin desmids. I. Aufwuchs and plankton communities of selected acid bogs,alkaline bogs,and closed bogs

Data are presented for 28 acid bogs, five alkaline bogs, and 12 closed bogs in Wisconsin with respect to the summer composition of the aufwuchs and plankton ccommunities, the relative importance of desmids in these communities, and the structure of aufwuchs communities associated with different macrophyte hosts. Generic diversity of desmids is highest in acid bogs and lowest in alkaline bogs and generally is greater in the aufwuchs community than in the plankton community at a given site. Whenever it was present, the greatest diversity occurred in association with the macrophyte host Utricularia. Among lakes of a given type, relationships between the occurrence of desmid genera and parameters of the chemical environment were not apparent for either the aufwuchs or plankton communities. Similarly, no clear-cut distinctions occur in the desmid communities of the three lake types in terms of population densities and percentage contribution to the total population, but acid bogs tend to have a somewhat more prominent flora quantitatively. Statistically significant differences in desmid population densities from one host to another within a given lake did occur in lakes of all three types, and this suggests that the nature of the substrate can definitely influence community size and composition. Data for other algal groups are similarly treated, and brief comparisons of the mat and open water communities of alkaline bogs are included.     

Methanotrophic bacteria in cold seeps of the floodplains of northern rivers

Small mud volcanoes (cold seeps), which are common in the floodplains of northern rivers, are potentially important (although poorly studied) sources of atmospheric methane. Field research on the cold seeps of the Mukhrina River (Khanty-Mansiysk Autonomous okrug, Russia) revealed methane fluxes from these structures to be orders of magnitude higher than from equivalent areas of the mid-taiga bogs. Microbial communities developing around the seeps were formed under conditions of high methane concentrations, low temperatures (3–5°C), and near-neutral pH. Molecular identification of methane-oxidizing bacteria from this community by analysis of the pmoA gene encoding particulate methane monooxygenase revealed both type I and type II methanotrophs (classes Gammaproteobacteria and Alphaproteobacteria, respectively), with prevalence of type I methanotrophs. Among the latter, microorganisms related to Methylobacter psychrophilus and Methylobacter tundripaludum, Crenothrix polyspora (a stagnant water dweller), and a number of methanotrophs belonging to unknown taxa were detected. Growth characteristics of two methanotrophic isolates were determined. Methylobacter sp. CMS7 exhibited active growth at 4–10°C, while Methylocystis sp. SB12 grew better at 20°C. Experimental results confirmed the major role of methanotrophic gammaproteobacteria in controlling the methane emission from cold river seeps.     

Occurrence and metabolism of sphagnum acid in the cell walls of bryophytes

Sphagnum acid was detected in all 30 Sphagnum species investigated. The content declines in older stem segments. Investigations have so far failed to detect this cinnamic acid derivative outside the Sphagnales. In all the Sphagnum species analysed, a second, conspicuous substance was detected, apparently identical with a degradation product of sphagnum acid produced by enzymatic reaction with peroxidase in vitro. A casual correlation between the sphagnum acid content and peroxidase activity in vivo is discussed. Glyphosate (0.5 mM) inhibits the synthesis of sphagnum acid and shikimate accumulates. Exogenously supplied phenylalanine is able to produce up to 65% reversal of the glyphosate-mediated inhibition of sphagnum acid synthesis. A mixed effect of glyphosate was found on amino acid levels. The content of sphagnum acid is also reduced by daily application of 0.1 mM l-α-aminooxy-β-phenylpropionic acid.     

Conserving Scotland's raised bogs

Summary

Raised bog was always a relatively rare habitat in Scotland and, being mainly found in lowland areas, the habitat has had a long history of land-use and exploitation associated with it. Today, raised bogs are considered as one of Britain's rarest and most endangered habitats. As a consequence the Scottish Wildlife Trust ran a conservation programme (the Scottish Raised Bog Conservation Project) between 1993 and 1995 to set up a strategy which could conserve the remaining bogs. A major landcover survey executed under the auspices of the project revealed widespread damage although 9% of the resource remained in a ‘near-natural’ state. However, the continuing cumulative effects of centuries of small scale activities and the effects of past and present air-pollution places all sites under considerable threat. One way to counter such threats is to enact positive conservation management on sites. To date, most work has concerned vegetation and hydrological management on the mire surface. Initial analyses of monitoring programmes suggest this type of conservation management is having little impact across the whole site. It is suggested that more comprehensive programmes of management should now be undertaken to restore the hydrological system of the whole site including the surrounding lagg fens.     

Search for Methanotrophic Producers of Exopolysaccharides

Bacteria that produce exopolysaccharides (EPS) and use methane as the only source of carbon were selected by studying a collection of methanotroph strains: Methylococcus capsulatusE 494, 874, and 3009; M. thermophilus111p, 112p, and 119p; Methylobacter ucrainicus159 and 161; M. luteus57v and 12b; Methylobactersp. 100; Methylomonas rubra15 sh and SK-32; Methylosinus trichosporiumOV3b, OV5b, and 4e; M. sporium5,12, A20d, and 90v; and Methylocystis parvusOVVP. Mesophilic methanotroph strains with the ribulose monophosphate way of C₁-compound assimilation synthesized EPS more actively than bacteria operating the serine cycle. The dynamics of EPS synthesis by methanotrophs during chemostat cultivation was studied.