Highly Distinct Microbial Communities in Elevated Strings and Submerged Flarks in the Boreal Aapa-Type Mire

Large areas in the northern hemisphere are covered by extensive wetlands, which represent a complex mosaic of raised bogs, eutrophic fens, and aapa mires all in proximity to each other. Aapa mires differ from other types of wetlands by their concave surface, heavily watered by the central part, as well as by the presence of large-patterned string-flark complexes. In this paper, we characterized microbial diversity patterns in the surface peat layers of the neighboring string and flark structures located within the mire site in the Vologda region of European North Russia, using 16S rRNA gene sequencing. The microbial communities in raised strings were clearly distinct from those in submerged flarks. Strings were dominated by the Alpha- and Gammaproteobacteria. Other abundant groups were the Acidobacteriota, Bacteroidota, Verrucomicrobiota, Actinobacteriota, and Planctomycetota. Archaea accounted for only 0.4% of 16S rRNA gene sequences retrieved from strings. By contrast, they comprised about 22% of all sequences in submerged flarks and mostly belonged to methanogenic lineages. Methanotrophs were nearly absent. Other flark-specific microorganisms included the phyla Chloroflexi, Spirochaetota, Desulfobacterota, Beijerinckiaceae- and Rhodomicrobiaceae-affiliated Alphaproteobacteria, and uncultivated groups env.OPS_17 and vadinHA17 of the Bacteroidota. Such pattern probably reflects local anaerobic conditions in the submerged peat layers in flarks.

The distribution pattern of mire specialist butterflies in raised bogs of the northern lowlands of Central Europe

Raised bogs are extreme and azonal ecosystems with a characteristic hydrological balance, microclimatic conditions and a specific flora and fauna. Recently, these ecosystems have increasingly become the focus of scientific and general attention because of their important ecosystem roles in the face of global warming and providing biodiversity refuges. From a biogeographical and evolutionary context, the peat bogs of the European Lowlands serve as palaeorefugia, acting as cold, edaphic island habitats for arcto-alpine or boreo-montane insect species in temperate biomes. Analysing 105 peat bog sites in the northern lowlands of Central Europe, we compare the diversity and geographic distribution pattern of a subset of six butterfly species, which appear to be tyrphobiontic or tyrphophile mire specialists. We demonstrate a decrease in mean species number in the European Lowlands on a gradient from the east (Northern Belarus, about 4 species) to the west (Northern Germany, about 1 species), and suggest that the decreasing species number may be mainly caused by human impact in the past. The individual distribution pattern shows a nearly complete gap in occurrence of the sensitive bog specialist species Colias palaeno and Boloria eunomia in Northern Germany and an increasing presence of those species in peat bogs of eastern Europe. Boloria aquilonaris shows a different pattern, which, in contrast to C. palaeno, is continuously distributed in all sampled regions and seems to be the more tolerant of tyrphobiontic butterflies in the face of human impact on peat bogs. In the light of other recent findings our results also suggest that Boloria aquilonaris and Plebejus optilete may serve as target species reflecting success in ecological restoration of peat bog ecosystems.

Pinus mugo shrubs on peat bogs in the Tatra National Park

Pinus mugo shrubs on peat bogs in the Tatra National Park (TNP) were for the first time described as a separated plant association by Obidowicz (1975) from only two mires. Since then, there have been no studies on peat bogs in the TNP and they have not been mentioned in the list of vegetation types of the Park. The research regarding the dwarf pine shrubs on mires in the Tatra Mountains was carried out in 2019. We mapped all patches of such vegetation (total – ~2 ha) on which we made 26 relevés. P. mugo shrubs on peat bogs occur within the complex of mire habitats, such as Norway spruce bog woodlands, raised bogs and poor fens. The shrub layer is dominated by Pinus mugo with admixture of dwarfish Picea abies. Typical plants of the herb layer are Vaccinium myrtillus, V. vitis-idaea, Eriophorum vaginatum and Oxycoccus palustris, whereas the most common mosses are Sphagnum magellanicum, S. capillifolium, S. russowi, Pleurozium schreberi. P. mugo shrubs on peat bogs in the TNP belong to the association Sphagno magellanici-Pinetum mugo.

Rokubacteria in Northern Peatlands: Habitat Preferences and Diversity Patterns

Rokubacteria is a phylogenetic clade of as-yet-uncultivated prokaryotes, which are detected in diverse terrestrial habitats and are commonly addressed as members of the rare biosphere. This clade was originally described as a candidate phylum; however, based on the results of comparative genome analysis, was later defined as the order-level lineage, Rokubacteriales, within the phylum Methylomirabilota. The physiology and lifestyles of these bacteria are poorly understood. A dataset of 16S rRNA gene reads retrieved from four boreal raised bogs and six eutrophic fens was examined for the presence of the Rokubacteriales; the latter were detected exclusively in fens. Their relative abundance varied between 0.2 and 4% of all bacteria and was positively correlated with pH, total nitrogen content, and availability of Ca and Mg. To test an earlier published hypothesis regarding the presence of methanotrophic capabilities in Rokubacteria, peat samples were incubated with 10% methane for four weeks. No response to methane availability was detected for the Rokubacteriales, while clear a increase in relative abundance was observed for the conventional Methylococcales methanotrophs. The search for methane monooxygenase encoding genes in 60 currently available Rokubacteriales metagenomes yielded negative results, although copper-containing monooxygenases were encoded by some members of this order. This study suggests that peat-inhabiting Rokubacteriales are neutrophilic non-methanotrophic bacteria that colonize nitrogen-rich wetlands.

Peat-Inhabiting Verrucomicrobia of the Order Methylacidiphilales Do Not Possess Methanotrophic Capabilities

Methanotrophic verrucomicrobia of the order Methylacidiphilales are known as extremely acidophilic, thermophilic or mesophilic bacteria that inhabit acidic geothermal ecosystems. The occurrence of verrucomicrobial methanotrophs in other types of acidic environments remains an open question. Notably, Methylacidiphilales-affiliated 16S rRNA gene sequences are commonly retrieved from acidic (pH 3.5–5.5) peatlands. In this study, we compared the patterns of verrucomicrobial diversity in four acidic raised bogs and six neutral fens located in European North Russia. Methylacidiphilales-like 16S rRNA gene reads displaying 83–86% similarity to 16S rRNA gene sequences of currently described verrucomicrobial methanotrophs were recovered exclusively from raised bogs. Laboratory incubation of peat samples with 10% methane for 3 weeks resulted in the pronounced increase of a relative abundance of alphaproteobacterial methanotrophs, while no response was detected for Methylacidiphilales-affiliated bacteria. Three metagenome-assembled genomes (MAGs) of peat-inhabiting Methylacidiphilales bacteria were reconstructed and examined for the presence of genes encoding methane monooxygenase enzymes and autotrophic carbon fixation pathways. None of these genomic determinants were detected in assembled MAGs. Metabolic reconstructions predicted a heterotrophic metabolism, with a potential to hydrolyze several plant-derived polysaccharides. As suggested by our analysis, peat-inhabiting representatives of the Methylacidiphilales are acidophilic aerobic heterotrophs, which comprise a sister family of the methanotrophic Methylacidiphilaceae.

Characterization of peat deposit using ground penetrating radar: Survey experiments and data interpretation

The paper deals with the possibilities of different wave frequency antennae applications for estimation of the depth of peat deposits and detection of peat layers with different physical characteristics. We employed a GPR system “OKO-2” (“Logical systems”, Russia) with 250 MHz, 700 MHz, and 1700 MHz shielded antennae. The surveys were conducted in 2017–2019 within the pristine and drained raised bogs and swamp forest in the south taiga subzone of Western Siberia to assess the spatial differentiation of the peat deposit and the modern peat accumulation rate within drained bogs. The peculiarities of field surveying, GPR data processing and interpretation are shown. Based on GPR data analysis the influence zone of Bakchar bog and modern peat accumulation within drained bogs were assessed. We noted that the Bakchar bog has a vast zone of influence reaching 700 m from the bog border where peat accumulation is observed. The modern peat accumulation is observed within Bakchar the bog. Drained sites of Ust-Bakchar bog are characterised by the absent peat accumulation or degradation of the peat deposits.

Emerging forest–peatland bistability and resilience of European peatland carbon stores

Northern peatlands store large amounts of carbon. Observations indicate that forests and peatlands in northern biomes can be alternative stable states for a range of landscape settings. Climatic and hydrological changes may reduce the resilience of peatlands and forests, induce persistent shifts between these states, and release the carbon stored in peatlands. Here, we present a dynamic simulation model constrained and validated by a wide set of observations to quantify how feedbacks in water and carbon cycling control resilience of both peatlands and forests in northern landscapes. Our results show that 34% of Europe (area) has a climate that can currently sustain existing rainwater-fed peatlands (raised bogs). However, raised bog initiation and restoration by water conservation measures after the original peat soil has disappeared is only possible in 10% of Europe where the climate allows raised bogs to initiate and outcompete forests. Moreover, in another 10% of Europe, existing raised bogs (concerning ∼20% of the European raised bogs) are already affected by ongoing climate change. Here, forests may overgrow peatlands, which could potentially release in the order of 4% (∼24 Pg carbon) of the European soil organic carbon pool. Our study demonstrates quantitatively that preserving and restoring peatlands requires looking beyond peatland-specific processes and taking into account wider landscape-scale feedbacks with forest ecosystems.

ASSESSMENT OF THE LEVEL OF STRESS ON PLANTS OF WESTERN SIBERIAN RAISED BOGS BY THE METHOD OF FRACTAL ANALYSIS

Sufficient evidence has been collected that alternative biological and ecological processes may occur in individual plant specimens that dwell in environmentally equivalent habitats. Environmental stress triggers individual, specimen-specific adaptive response. The paper shows how fractal analysis can be used to study the degree of stress that plants in different habitats and environmental factor combinations are exposed to.