Decomposition of Sphagnum mosses in Western Siberia bog ecosystems (on the example of Sphagnum fuscum)

On the base of experiments there were recorded the greatest mass losses of Sphagnum fuscum samples flat palsa mires in the first year of experiment, in the following years decay rate decreased significantly (from 24 % to 16 %). On middle taiga bogs there was observed decay rate increasing over the third year while on southern taiga bogs Sphagnum fuscum was decomposed almost evenly over three years. On ridges of ridge-hollow complex of middle taiga and southern taiga mass losses under destruction were greater than those in ryams. The most dynamic decomposition was recorded for forest-steppe ryam with decay mass losses over three years of 56% average.

Bog plant/lichen tissue nitrogen and sulfur concentrations as indicators of emissions from oil sands development in Alberta, Canada

Increasing gaseous emissions of nitrogen (N) and sulfur (S) associated with oil sands development in northern Alberta (Canada) has led to changing regional wet and dry N and S deposition regimes. We assessed the potential for using bog plant/lichen tissue chemistry (N and S concentrations, C:N and C:S ratios, in 10 plant/lichen species) to monitor changing atmospheric N and S deposition through sampling at five bog sites, 3–6 times per growing season from 2009 to 2016. During this 8-year period, oil sands N emissions steadily increased, while S emissions steadily decreased. We examined the following: (1) whether each species showed changes in tissue chemistry with increasing distance from the Syncrude and Suncor upgrader stacks (the two largest point sources of N and S emissions); (2) whether tissue chemistry changed over the 8 year period in ways that were consistent with increasing N and decreasing S emissions from oil sands facilities; and (3) whether tissue chemistry was correlated with growing season wet deposition of NH4+-N, NO3−-N, or SO42−-S. Based on these criteria, the best biomonitors of a changing N deposition regime were Evernia mesomorpha, Sphagnum fuscum, and Vaccinium oxycoccos. The best biomonitors of a changing S deposition regime were Evernia mesomorpha, Cladonia mitis, Sphagnum fuscum, Sphagnum capillifolium, Vaccinium oxycoccos, and Picea mariana. Changing N and S deposition regimes in the oil sands region appear to be influencing N and S cycling in what once were pristine ombrotrophic bogs, to the extent that these bogs may effectively monitor future spatial and temporal patterns of deposition.

Ultraviolet absorbance of Sphagnum magellanicum, S. fallax and S. fuscum extracts with seasonal and species-specific variation

Bryophytes, including Sphagnum, are common species in alpine and boreal regions especially on mires, where full sunlight exposes the plants to the damaging effects of UV radiation. Sphagnum species containing UV-protecting compounds might offer a biomass source for nature-based sunscreens to replace the synthetic ones. In this study, potential compounds and those linked in cell wall structures were obtained by using methanol and alkali extractions and the UV absorption of these extracts from three common Sphagnum moss species Sphagnum magellanicum, Sphagnum fuscum and Sphagnum fallax collected in spring and autumn from western Finland are described. Absorption spectrum screening (200–900 nm) and luminescent biosensor (Escherichia coli DPD2794) methodology were used to examine and compare the protection against UV radiation. Additionally, the antioxidant potential was evaluated using hydrogen peroxide scavenging (SCAV), oxygen radical absorbance capacity (ORAC) and ferric reducing absorbance capacity (FRAP). Total phenolic content was also determined using the Folin-Ciocalteu method. The results showed that methanol extractable compounds gave higher UV absorption with the used methods. Sphagnum fallax appeared to give the highest absorption in UV-B and UV-A wavelengths. In all assays except the SCAV test, the methanol extracts of Sphagnum samples collected in autumn indicated the highest antioxidant capacity and polyphenol content. Sphagnum fuscum implied the highest antioxidant capacity and phenolic content. There was low antioxidant and UV absorption provided by the alkali extracts of these three species.

Pigment Composition of Sphagnum fuscum of Wetlands under Anthropogenic Impact

Oligotrophic bogs prevail among wetlands in the mainland of the North of Russia. The study of the moss cover response to the increase in anthropogenic load makes it possible to reveal a shift in the ecological balance of bog ecosystems. The goаl of the research is to reveal changes in the pigment apparatus of the moss cover under drainage, road construction and mining operation as in the case of the Arkhangelsk region. Sphagnum fuscum (Schimp.) H. Klinggr. was used as the main object for studying the pigment composition of the photosynthetic apparatus. A change in the pigment composition during the drainage of bogs was found when comparing the pigments of S. fuscum moss on the undisturbed Ilas bog massif and the drained bog massif “Ovechye”; the content of carotenoids decreases and the content of chlorophyll a increases. The influence of the traffic load was studied in an open wetland of the Mezen district, where there is no tree-shrub layer. Succession of dominant species is observed in the moss-lichen layer of the bog in the immediate vicinity of the road (34 m); the projective cover of sphagnum mosses decreases to less than 10 %, and brie mosses emerge as dominants. The content of all analyzed pigments in moss samples increases with the distance from unpaved roads, especially the content of chlorophylls (>5 times at a distance of 100 m and more). As an example of the anthropogenic impact of a mining enter prise, we used terricones of the Lomonosov Mining and Processing Plant, PJSC Severalmaz, from which aeolian transport of dust particles of rocks containing saponite occurs. Near the pollution source, the content of total moss pigments is noticeably lower than in the area protected by a forest belt. A decrease in the proportion of chlorophylls a and b with a slight increase in the content of carotenoids was found in the pigment complex. The changes are due to the transfer of saponite; a clay mineral that actively absorbs water. The increased moisture provides favorable conditions for the moss vegetation, which mitigates the negative effect of pollutants on the pigment apparatus of plants. Overall, pigments content change represents plants adaptation to the adverse impacts and anthropogenic pressing.

Spatial pattern of intraspecific trait variability in Sphagnum fuscum

Recent studies have shown that intraspecific variability is a mechanism by which species respond to environmental heterogeneity, and that intraspecific variation can have large implications for ecological processes. Here, we studied whether there is meaningful intraspecific variation in the ecohydrological traits, biomass allocation, and decomposability in Sphagnum moss, and if so, to explore the spatial pattern of variability. We implemented a hierarchical design in which we quantified traits of S. fuscum at three spatial scales: (i) between individuals within 8 cm2 patches; (ii) between replicate patches located within a single hummock or hollow location; and (iii) between hummocks. Although we focused on S. fuscum, we also compared the variability in some morphological features of S. fuscum and S. magellanicum. If growth is affected by density, we expected variability to be lowest at the patch level. Contrary to our expectation, most of the variability in both species occurred within-patch, which is our smallest sampling unit. Variability was generally higher in the traits for S. magellanicum compared with the variability in the traits for S. fuscum, which was generally negligible. Also, the pattern of variability observed for some of the traits such as the capitulum mass suggests that the mechanisms controlling different traits may be operating at different spatial scales.

Decomposition rate of peat-forming plants at the initial stages of destruction in peat deposits of the oligotrophic bogs “Bakcharskoe” and “Timiryasevskoe”

The research presents quantitative estimates of the decomposition rate of plant residues at the initial stages of the decay of four plant species (Eriophorum vaginatum, Carex rostrata, Sphagnum fuscum, Sphagnum angustifolium) in peat deposits of the oligotrophic bogs in the southern taiga subzone of Western Siberia. We also studied the change in the content of total carbon, nitrogen and ash elements in plant residues and the activity of microflora at the initial stages of decomposition. The studies were conducted in the bogs characterized by various hydrothermal conditions. At the initial stage of the decay of peat-forming plants the maximum losses of mass occur in the first month of the experiment and reach 36-52% of the total loss of organic matter during the growing season. Sphagnum fuscum is the most resistant to decomposition. The most intense decomposition of Sphagnum fuscum at the initial stages of decomposition is characteristic for warmer and less humid conditions of the Timiryazevskoe bog. It was revealed that mass losses of organic matter correlate well with total carbon losses. The most intensive decreasing of the total carbon content as well as mass loss of organic matter are observed after the first month of the experiment. The maximal decline of carbon in plant residues was received for Eriophorum vaginatum. During the decomposition of plant residues, the nitrogen content was decreasing, and the most intense nitrogen losses were characteristic for Sphagnum mosses. Nitrogen loss in peat-forming plants during the first month of decomposition varies depending on the locality conditions, but it becomes equal during the later decomposition stages. At the first stages of decomposition of plant residues, both the accumulation and the loss of ash elements were observed in the samples. Both the Bakcharskoe and Timiryazevskoe bogs were characterized by the accumulation of ash elements in plant samples of Eriophorum vaginatum. Dynamics of mass loss and removal of elements are directly related to the activity of microorganisms. The maximum number of microorganisms was found in July and September. Peat and plant samples located in the peat deposit of the Timiryazevskoe bog are more saturated with microorganisms of the nitrogen cycle, and samples from the Bakcharskoe bog are richer in carbon cycle microorganisms. Microorganisms of the lignocellulosic complex were less active as compared with other groups of microorganisms. The number of microorganisms assimilating the mineral forms of nitrogen are on average 1.5 times less than the number of microorganisms assimilating the organic forms. The positive correlation between the nitrogen content and the number of fungi was found. In addition, correlation between the numbers of denitrifiers and oligotrophs was found. It is explained by trophic relationshipsbetween these groups of microorganisms.

INVESTIGATION OF ANTIOXIDANT ACTIVITY OF PEAT LIPIDS AND SAPROPELS FROM WESTERN SIBERIA

The antioxidant activity of lipids extracted from peats and sapropels from Tomsk and Novosibirsk Regions and Khanty-Mansi Autonomous Okrug is estimated by microcalorimetry. The presence of antioxidants (AO) in the lipids of all peats under study and in a sapropel from the Dolgoye Lake is confirmed by the presence of an induction period (950–14000 s) on the heat release curve and the decrease in the final rate of the model reaction of the initiated cumene oxidation by 25–90%. The total amount of lipid antioxidants varying within the range (22–183)∙10-3 mol/kg is determined by the degree of inhibition of the oxidation reaction. The concentration of identified organic compounds (25–186 μg/g) including alkanes, fatty acids, steroids, terpenoids, and tocopherols is determined by chromatography-mass spectrometry, which correlates with the amount of AO in the peat. It is shown that the samples of initial peats are ordered by their antioxidant activity as follows: sphagnum fuscum > cotton grass > lowland wood > sphagnum phallax. Sphagnum fuscum peats are characterized by the maximum biological activity, which makes it possible to recommend them as an optimal raw material for practical use.