The humification of high-moor peat

Summary It has been observed that dark coloured substances are formed by soil micro-organisms (Pseudomonas, Arthrobacter-Corynebacterium-Nocardia group, spore forming bacteria and Streptomyces) from aromatic compounds,e.g. phenol, benzoic acid, guaiacol, toluene, phthalic acid, catechol, tyrosine, and tryptophane. The dark-brown to black substances formed by these organisms possess humus-like qualities and have the appearance of dopplerite. Reducing substances reacting in the cold with triphenyl tetrazolium chloride are formed as intermediates. It is suggested that these intermediary substances are quinones, or semiquinones and that these occur as free radicals which subsequently polymerize to humus-like substances.     

Number,viability, and diversity of the filterable forms of prokaryotes in sphagnous high-moor peat

The number, potential viability, and taxonomic diversity (at the level of phylum) of the filterable forms of prokaryotes (FFP) are estimated in the main genetic horizons of high-moor peat. It was shown that the number of FFP reached 500 million cells in 1 g, i.e., up to 5% of the general size bacteria. The portion of viable cells among FFP (93–98%) was higher than that for the general size bacteria (60–68%). FISH-analysis (fluorescence in situ hybridization) showed that FFP contained the same phylogenetic groups as the population of general size bacteria (domain Archea and phylum Actinobacteria, Cytophaga, and Proteobacteria of the domain Bacteria).     

The microbiology of cut-away peat

Summary Fungi occurring commonly in cut-away peat were selected for autecological study, being chosen to represent both cosmopolitan and indigenous elements of the peat flora. A fungus alien to peat,Fusarium culmorum, was also included in the study. The germination in peat of the spores of these species and their ability to grow and colonise organic material added to peat were examined. It was concluded that the cosmopolitan element was composed of efficient saprophytes but that the ability of their spores to germinate in unamended peat was limited. Although Fusarium spores germinated, the germ tubes subsequently formed chlamydospores. Only spores of the indigenous peat fungi germinated well in peat but their growth habit was not suited to the colonisation and utilisation of organic matter, added to peat, in competition with the cosmopolitan flora. The concept of ‘source potential’ is introduced to explain the variance in fungal growth from different substrate bases.     

Studies on peat and peat microorganisms

Summary The isolation of thermophilic fungi from peat is reported and their taxonomy is discussed. Mucor pusillus was frequently found in peat. Humicola was recorded for the first time as occurring in peat. The thermophilic strains were classified as H. insolens, H. stellatus, and H. lanuginosus respectively. Paecilomyces commonly occur in peat. Up to now only thermotolerant Pacecilomyces were reported. Our thermophilic strains resemble Paecilomyces in appearance, but after detailed examination may belong to the related genera Talaromyces or also Thermoascus.Because of its wide temperature range Aspergillus fumigatus was very frequently isolated under thermophilic conditions.Part I.: see Küster, E., and R. Locci: Arch. Mikrobiol. 45, 188–197 (1963).     

Studies on peat and peat microorganisms

Summary Thermophilic Actinomycetes were isolated from various peat samples and examined in detail. Most of them were classified as Thermoactinomyces vulgaris, a species which frequently occurs in very different habitats.The characters which separate Thermoactinomyces thalpophilus from Thermoactinomyces vulgaris are discussed. They are unstable and not sufficiently characteristic so that the taxonomic position of Thermoact. thalpophilus now becomes doubtful. Thermomonospora viridis comb. nov. which is distinguished by a graygreen aerial mycelium and the formation of a green pigment has been particularly studied and described. Thermoactinomyces monosporus Schütze and Thermoactinomyces viridis Schuurmans are synonyma. Streptomyces strins isolated and grown at 45° C should be called thermotolerant rather than thermophilic. They differ from known nesophilic species in their temperature requirements only.     

The influence of peat extract onClostridium acetobutylicum

Summary The effects of peat extract onCl. acetobutylicum appear to be at least two-fold. It is a source of mineral nutrients and it functions as a buffering agent in the presence of a semi-synthetic medium.     

The bacterial population of a blanket peat

The number of aerobic bacteria in a blanket peat decreased with depth from 26 times 10⁶/g dry peat in the surface layers to 0.5 times 10⁶/g dry peat at 30–40 cm down the profile, thereafter remaining roughly constant. Obligate psychrophiles comprised <2.5% of this population. Anaerobes were most numerous, 9 times 10⁶/g dry peat at 6–10 cm depth, decreasing to 0.5 times 10⁶/g at 20–30 cm. Calculations indicated that these counts, 10³–10⁴-fold lower than the direct counts, substantially underestimated the active microbial population. Gram negative rods, the predominant aerobes in the surface layers, were replaced by unidentified Bacillus strains at 10–20 cm depth but became increasingly more numerous further down the profile. The Gram negative rods were the most numerous organisms/m² but the Bacillus strains, one third of which were present as spores, made the largest contribution to the biomass/m². Gram positive cocci, Arthrobacter and, infrequently, Nocardia were also isolated. Actinomyces -like forms were the predominant obligate anaerobes and were approximately three times more numerous than clostridia and a curved Gram negative rod.     

Mineralization rates of peat from eroding peat islands in reservoirs

Reservoirs are sources of greenhouses gases to the atmosphere, primarily due to organic carbon mineralization in flooded plants and soils to carbon dioxide (CO₂) and methane (CH₄). Floating peat islands are common in reservoirs that inundated peatlands. These islands can decompose on mass, or small pieces of peat can erode from islands to decompose in the water column or on the bottom of reservoirs. Here we used large 450 liter sealed enclosures to measure mineralization rates of small peat pieces and larger peat blocks collected from floating peat islands. Mineralization rates were calculated by quantifying dissolved inorganic carbon (DIC), CO₂ and CH₄ accumulation within the water and headspace of the enclosures over time. We found that peat did decompose under water, but rates of mineralization of peat pieces were not different than rates of mineralization of larger peat blocks. Mineralization rates ranged between 59 and l40 g C g^–1 d^–1. Peat pieces acidified the water, shifting the bicarbonate equilibrium to almost exclusively dissolved CO₂, which was then readily able to flux to the atmosphere. We estimated that 2.4–5.6% of peat carbon was mineralized annually, suggesting that fluxes of CO₂ and CH₄ from reservoirs that flood peatlands could last at minimum 18–42 years from this carbon source alone.     

Interdependence of peat and vegetation in a tropical peat swamp forest

The visual uniformity of tropical peat swamp forest masks the considerable variation in forest structure that has evolved in response to differences and changes in peat characteristics over many millennia. Details are presented of forest structure and tree composition of the principal peat swamp forest types in the upper catchment of Sungai Sebangau, Central Kalimantan, Indonesia, in relation to thickness and hydrology of the peat. Consideration is given to data on peat geochemistry and age of peat that provide evidence of the ombrotrophic nature of this vast peatland and its mode of formation. The future sustainability of this ecosystem is predicted from information available on climate change and human impact in this region.     

The physiology of some blue-green algal isolates from peat

An investigation of the physiology of a number of blue-green algae isolated from peat sites in Glenamoy, Co. Mayo, is reported. Physical and nutritional parameters were studied and correlated to the conditions prevailing in the natural environment of the algae. The occurrence of blue-green algae in peat was found to be controlled by the pH level and the presence of phosphorus in the environment.     

Surface peat structure and chemistry in a tropical peat swamp forest

Background and Aims

Tropical peat swamp forests (PSF) are great stores of terrestrial carbon and host unique biodiversity. Despite their importance for carbon accounting, the peat characteristics are sparsely studied, and the effect of microtopography on peat properties has not been reported before.

Methods

We compared PSF peat soil characteristics down to 70 cm under differing microtopographical conditions and hydrology.

Results

Long-term water table level data combined with the data from peat structure and chemistry analyses showed differences in most of the measured properties between hummocks and hollows. Decomposition degree was lowest at hummock and hollow surfaces while bulk density and C content increased towards deeper peat. Ash, P, K, Ca and Mg had highest concentrations on hummock surfaces with declining trend downwards, whereas N had no clear concentration pattern along the elevation gradient.

Conclusions

The microtopographical features may not only differ in regards to the water table-induced oxygen conditions but also due to differences in nutrient dynamics.     

The contribution of rewetting to vegetation restoration of degraded peat meadows

Question: What is the contribution of a rise in groundwater level to vegetation restoration of degraded peat meadows compared to abandonment only? Location: Abandoned peat meadows in the central part of The Netherlands. Methods: Comparison of species composition and species abundance of vegetation and seed banks of reference and rewetted peat meadows, using plant trait and seed bank analysis. Results: Vegetation of rewetted meadows shared on average only 27% of their species with the reference meadow, while this was 50% on average for species in the seed bank. Rewetted meadows had a lower total number of species and a lower number of wet grassland and fen species present in the vegetation, but had higher species richness per m², although evenness was not affected. Rewetting increased the dominance of species of fertile and near neutral habitats, but did not result in an increase of species of wet or waterlogged habitats. Re-wetted meadows were dominated by species relying mainly on vegetative reproduction and species with a low average seed longevity compared to the reference meadow. Conclusion: Rewetting was not effective as a restoration measure to increase plant species diversity or the number of wet grassland and fen species in the vegetation. If no additional restoration management is applied, the seed bank will be depleted of seeds of species of wet grassland or fen habitats, further reducing the chances of successful vegetation restoration.     

The importance of floating peat to methane fluxes from flooded peatlands

The effect of flooding on methane (CH₄) fluxes was studied through the construction of an experimental reservoir in a boreal forest wetland at the Experimental Lakes Area in northwestern Ontario. Prior to flooding, the peatland surface was a small source of CH₄ to the atmosphere (1.0± SD of 2.3 mg CH₄ m^–2 d^–1). After flooding, CH₄ fluxes from the submerged peat surface increased to 64±68 mg CH4 m^–2 d^–1 CH₄ bubbles within the submerged peat caused about 1/3 of the peat to float. Fluxes from these floating peat islands were much higher (440±350 mg CH₄ m^–2 d^–2) than from both the pre-flood (undisturbed) and the post-flood (submerged) peat surfaces.The high fluxes of CH₄ from the floating peat surfaces may be explained by a number of factors known to affect the production and consumption of CH₄ in peat. In floating peat, however, these factors are particularly enhanced and include decreased oxidation of CH₄ due to the loss of aerobic habitat normally found above the water table of undisturbed peat and to increased peat temperatures. The extremely high fluxes associated with newly lifted peat may decrease as the islands age. However, CH₄ flux rates from floating peat islands that were several years old still far exceeded those from undisturbed peat surfaces and from the water surface of a newly created reservoir.     

The production of surfactin by Bacillus subtilis grown on peat hydrolysate

Summary Horticultural grade sphagnum peat was subjected to acid hydrolysis under various conditions. The hydrolysis was accomplished with concentrations of sulphuric acid between 0.5 and 2% for either 1 or 2 h at 124°C. Six monosaccharides in the hydrolysate were identified by HPLC analysis. A maximum sugar concentration of 7.7g/l was obtained with glucose accounting for 46% of the total. Bacillus subtilis was able to fully utilize all six sugars when the hydrolysate was supplemented with sufficient diammonium phosphate. The production of surfactin seemed to depend on the carbon-nitrogens balance and was inversely correlated to biomass production. With the selection of the proper hydrolysis conditions and nutrient levels the quantity of surfactin produced was as high as with a conventional glucose and mineral salts medium. The surfactin could be used in a peat dewatering process or sold as a co-product from a peat production facility.