Great Vasyugan Mire Research Articles

Seasonal Stream Water Chemistry Response To Long-Term Forestry Drainage And Wildfire: A Case Study In A Part Of The Great Vasyugan Mire

Recent research suggests that climate change is contributing to rising solute concentrations in streams. This study focuses on assessing the concentrations of major elements, nutrients, and dissolved organic carbon (DOC), and their release through the bog-river system in the taiga zone of Western Siberia. The research was carried out in the northeastern part of the Great Vasyugan Mire (GVM), the largest mire system that impacts the quality of river water in the Ob River basin. By using PCA and cluster analysis, we examined the long-term dynamics of the chemical composition of headwater streams of the GVM affected by drainage and wildfires. Our data from 2015-2022 revealed that the concentrations of Са2+, Mg2+, K+, Na+, and HCO3- in stream water from the drained area of the GVM were, on average, 1.3 times lower than those at the pristine site. Conversely, the concentrations of NH+4, Fetotal, Cl-, SO42-, NO-3, DOC, and COD were higher, indicating the influence of forestry drainage and the pyrogenic factor. Our findings also demonstrated that the GVM significantly impacts the water chemical composition of small rivers. We observed a close correlation in the concentrations of К+, Na+, Cl-, Fetotal, NH+4, HCO3-, and COD between the GVM and the Gavrilovka River waters. PCA analysis revealed that air temperature influences the concentrations of Са2+, Mg2+, NH4+, NO3-, HCO3-, Fetotal, and DOC in the studied streams, with an inverse correlation with river discharge. The removal of major elements, nutrients, and DOC from the drained area of the GVM was most pronounced in April, being twice as high as in the pristine area. However, the total export from the drainage area of the Gavrilovka in April-September 2022 was 1.3 times lower than in the pristine area, amounting to 8487 kg/km2, with DOC removal at 42%.

Post-pyrogenic Changes in the Microflora and Water Chemistry of the Drained Part of the Great Vasyugan Mire (Tomsk Region)

Post-pyrogenic Changes in the Microflora and Water Chemistry of the Drained Part of the Great Vasyugan Mire (Tomsk Region)

Degradation of peat-forming plants at the first stages of decomposition in natural and post-pyrogenic peatlands of West Siberia

The aim of the study. Assessment of the phytomass stocks and decomposition rate of peat-forming plants’ residues in peat deposits of natural and post-pyrogenic peatlands at the initial stages of decomposition. Location and time of the study. The study was carried out in 2022 (May-September) at two oligotrophic bog sites: “Bakcharskoye” (field station “Vasyuganye”, IMCES SB RAS) and “Iksinskoye”, which are located in the north eastern spurs of the Great Vasyugan mire in the Bakcharsky and Shegarsky districts of the Tomsk region, Russia. Methods. The phytomass stocks were determined by the cutting method. The following fractions were separated: living phytomass (annual and perennial photosynthetic phytomass, i.e. green parts of grasses, shrubs leaves, mosses); perennial non-photosynthetic phytomass, i.e. shrubs stems, roots of grasses and shrubs; and dead phytomass (mortmass), i.e. litter, moss litter, standing dead phytomass. The decomposition rate of plant residues was determined by the method of litter bags placement in peat (Chamaedaphne calyculata, Sphagnum fuscum, Mixed sample consisting of 60% S. fuscum and 40% Ch. calyculata). In the initial and decomposed samples, the ash content was determined by the dry combustion method. The total carbon and nitrogen content, as well as the carbon and nitrogen isotopic composition, were determined using a DELTA V Advantage isotope ratio mass spectrometer. Results. This short-term study conducted during the growing season in conditions of undisturbed (Natural Ryam) and post-pyrogenic (Gar) phytocenoses showed that due to a significant amount of mortmass (2402 g/m2) Natural Ryam had organic matter stock exceeding that in the Gar by 1.7 times. On average, 59% of organic matter loss from the total losses during the growing season occurred in the first month. In both Gar and Natural Ryam conditions, minimal losses of organic matter were characteristic for Sphagnum fuscum (3.1 and 3.5% respectively). For the remaining samples the Gar conditions were more favorable for the degradation at the initial stages of decomposition. The Mixed sample occupied an intermediate position between its individual components in terms of mass losses. Carbon losses correlated well with mass losses both over 1 month of degradation (r=0.87) and over 4 months (r=0.96). In contrast to carbon, nitrogen accumulated in the Mixed sample at the initial stages of degradation, both after 1 month and 4 months. Conclusions. With smaller phytomass stocks in areas of post-pyrogenic succession, more active decay at the initial stages of organic matter decomposition occurs exactly under these conditions. The impact of post-pyrogenic succession on the rate of organic matter decomposition of Chamaedaphne calyculata plant residues and the Mixed sample was demonstrated. The most intensive decomposition of litter occured during the first month of degradation. Additionally, in the conditions of a burnt bog, a more intense release of nitrogen from all plant residues and accumulation of ash elements in Sphagnum fuscum samples were observed. The mixing of litter components influenced both the rate and dynamics of decomposition. The carbon and nitrogen isotopic composition began to change during the initial stages of decomposition, leading to enrichment with heavier isotopes 15N and 13C. This research emphasizes the importance of studying the processes of plant litter decomposition at the initial stages and considering the plant residue composition when studying the processes of organic matter transformation.

The effects of long-term drainage and wildfires on water table level and water chemistry of the Great Vasyugan Mire

In this paper, we assessed long-term changes in water table level of the Great Vasyugan Mire, water chemistry and the removal of mineral and organic substances in the mire-river system in the taiga zone of Western Siberia under the conditions of forest reclamation, pyrogenic factor and climate change. In the drained area of the Great Vasyugan Mire, a significant decrease in water table levels and an increase in the amplitude of their fluctuations by 1.6 times were noted. The effect of the pyrogenic factor is expressed, on the contrary, in an increase in water table levels due to surface burnout. In the water of the drained part of the Great Vasyugan Mire, an increase in the concentrations of Са2+, Mg2+, Fetotal, Cl-, К+, Na+, Cl-, SО42–, NO3-, DOC was noted. An increase in the content of NH+4, Feобщ, Cl-, SO42-, NO-3, and DOC is observed in river waters. An indicator of the effect of the pyrogenic factor on the chemical composition is an increase in the pH value and the content of K+, Na+, SО42–, NО–3, HCО3– ions, as well as Са2+, Mg2+, Feобщ. In connection with the overgrowth of the ditches, the process of self-healing of the mire is observed, and backwater zones are formed near the ditches and the amplitude of level fluctuations increases, as a result, the chemical composition of the waters of the drained and natural areas of the Great Vasyugan Mire in certain periods has minimal differences. Studies have shown that the removal of mineral and organic substances from the drained area of the great Vasyugan Mire prevailed in the high-water year 2018 and amounted to 2054 tons, of which the removal of DOC was equal to 47% or 969 tons. In the future, climate change, an increase in air temperature and precipitation in the region are likely, will contribute to the removal of biogenic elements and organic substances from mires and increase their concentration in river waters.

Использование вегетационных и водных индексов для оценки состояния постпирогенных верховых болот Западной Сибири

The article presents an analysis of the using vegetation and water indices possibilities to assess the pyrogenic load and post-pyrogenic vegetation restoration in raised bogs. The object of the study is burned out in 2016 site within the drained part of the Great Vasyugan mire. The research based on the vegetation field description data carried out in 2023 and Landsat 8 satellite data. Vegetation (NDVI, VARI, NBR) and water (NDWI WRI) indices for field research plots were calculated, and a statistical analysis of their interrelationships with the degree of pyrogenic load and characteristics of vegetation cover was performed using the principal component method. The effect of the wildfire was manifested in the partial or complete burning of the surface, trees, dwarf shrubs and mosses. Seven years after the fire, there was an almost complete restoration of dwarf shrubs, the appearance of pine and birch undergrowth, intensive overgrowth of burnt surfaces by Polytrichum strictum, and the restoration of sphagnum mosses began. The study showed that the values of all the considered indices, with the exception of NDVI, are lower at post-pyrogenic points compared to unburned ones. Of all the indices considered, NDWI showed the maximum dependence on the proportion of surface burnout and projective coating with sphagnum mosses. Water indices turned out to be more suitable in comparison with vegetation indices for assessing pyrogenic load and trends of post-pyrogenic restoration in conditions of raised bog. The results obtained will be used to create training inputs for decoding satellite data and to conduct a spatial and temporal assessment of the restoration of post-pyrogenic sites.

Water table level dynamics in the drained part of the great Vasyugan mire

Relevance. The need to assess mire-river interaction in Western Siberia under the influence of drainage and the pyrogenic factor. Aim. To study water table level dynamics in the Great Vasyugan Mire and the patterns of its change under the influence of drainage and the pyrogenic factor. Objects. Nоrtheastern part оf the Great Vasyugan Mire clоse tо Pоlynyanka village, Bakchar district, Tоmsk regiоn. Methods. Hydrological monitoring of drained and pristine part of the Great Vasyugan Mire is organized within the small model catchments of the Gavrilovka River and Klyuch River in the Vasyugan station of the Siberian Research Institute of Agriculture and the Peat branch of the Siberian Research Institute оf Agriculture and Peat RAS. Water table level monitoring was carried out in 2022 using Solinst Levelloger (Canada) with a frequency of 1 hour. River discharge measurements were made in different water periods using an acoustic current meter OTT Hydromet. The research methodology included an assessment of the spatial and temporal variation in water levels over the drained territory of the Great Vasyugan Mire in the Gavrilovka River basin in comparison with pristine part and depending on the main meteorological factors, correlation curves construction of mire water level and river discharges, the specific yield calculation. Statistical analysis of the data was carried out using the nonparametric Wilcoxon test, correlation and cluster analysis. Results. The studies shown that the drained area of the Great Vasyugan Mire within the Gavrilovka River basin is characterized by a significant transformation of the hydrological regime; there is a significant decrease in the water levels and an increase in the amplitude of their fluctuations. The influence of the pyrogenic factor is expressed in a certain increase in water levels as a result of the surface burnout and the leveling of microtopography. An analysis of the spatial variation of the water levels showed that it depends on the vegetation type of key sites, the slope of the surface, and the degree of surface burnout. It also depends on the location of the site relative to the lagg area, zones of backwater flow formed near overgrown drainage ditches, dirt roads and main ditch drainage zones. As a result of the forest reclamation and fire event in the study area of the Great Vasyugan Mire, active decomposition of plant residues was noted. This led to a decrease in the storage capacity (specific yield) of the upper peat layer. A decrease of the specific yield will increase the runoff from the mire area, which means the increase of possibility of extreme hydrological events in the conditions of growth in the amount of precipitation.

Soil Water Regime, Air Temperature, and Precipitation as the Main Drivers of the Future Greenhouse Gas Emissions from West Siberian Peatlands

This modeling study intended to solve a part of the global scientific problem related to increased concentrations of carbon dioxide in the atmosphere via emissions from terrestrial ecosystems that, along with anthropogenic emissions, make notable contributions to the processes of climate change on the planet. The main stream of CO2 from natural terrestrial ecosystems is related to the activation of biological processes, such as the production/destruction of plant biomass. In this study, the Wetland-DNDC computer simulation model with a focus on nitrogen and carbon biogeochemical cycles was used to study the effect of hydrothermal conditions on greenhouse gas fluxes in West Siberian peatlands. The study was implemented on the site of the world’s largest pristine wetland/peatland system, the Great Vasyugan Mire (GVM). The study was carried out based on data from permanent measurements at meteo stations and our own in situ measurements of hydrological and thermal parameters on sites, which allowed for testing different scenarios of changes in environmental conditions (temperature, precipitation, groundwater level) together with a change in GHG fluxes. The study revealed the air temperature and the level of groundwater as the main drivers controlling CO2 fluxes. The study of different scenarios of change in annual air temperature revealed the threshold of change in the wetland/peatland ecosystem from carbon sink to carbon source to the atmosphere to happen with an increase in the average annual air temperature by 3 °C with reference to the average annual air temperature values in 2019. Also, we found that the wetland/peatland ecosystem turned to act as an active carbon sink with about 7 cm increase in annual groundwater level, compared with its base level of −21 cm.

Dynamics of the heavy metals content (Zn, Cd, Pb, Cu) during the decomposition of sphagnum moss at the drained and post-pyrogenic sites of oligotrophic bogs

The aim of the study. Assessment of heavy metals (Zn, Cd, Pb, Cu) dynamic during the decomposition of Sphagnum fuscum L. in native, drained and post-pyrogenic oligotrophic peatlands. Location and time of the study. The study was carried out in 2019–2021 in two oligotrophic bogs: “Bakcharskoye” (field station “Vasyuganye” (IMCES SB RAS)) and “Iksinskoye”, which are the north-eastern spurs of the Great Vasyugan mire and located in the Bakcharsky district of the Tomsk region. Methods. Decomposition rate of Sph. fuscum L. was determined by the method of partially isolated samples, which is widely used to study the processes of transformation of plant material and peat. In the original and decomposed samples of sphagnum moss and peat soil (in layers 0-10, 10-20, 20-30), the ash content of peat was determined according to GOST-11306-83. The percentage of total carbon and nitrogen in samples of peat (up to 30 cm from the surface) and plant residues was determined together with the determination of isotopic composition using EA-IRMS (Elemental Analyzer/Isotope Ratio Mass Spectrometry). The concentrations of heavy metals (Zn, Cd, Pb, Cu) in samples of peat and plant residues were determined by stripping voltammetry. Results. Three-year experiment on decomposition of Sph. fuscum in four ecosystems (natural – VASnat, drained – VASdry, post-pyrogenic – Iksa 1 and Iksa2) showed that fire affected the decomposition rate: on average, mass loss in post-pyrogenic bogs was 1.4–1.6 times lower compared to the natural site. For almost all sites, a relationship was found between the mass loss and the concentration of heavy metals, with the exception of Cd during the first year of the experiment. The concentration of all elements in moss residues decreased during the decomposition process at all study sites. During moss decomposition the similarity in the release of biogenic elements Cu and Zn was recorded in the drained and post-pyrogenic sites (VASdry, Iksa1, Iksa2), while for Cd and Pb, which are not biogenic elements, such similarity was not revealed. Conclusions. Peat fires affect plant residue decomposition by decreasing its rate of decomposition. The study revealed incremental dynamics of HMs content in plant residues: at the initial stage, HMs are released, whereas during the second and third years, in some cases, the accumulation of HMs is observed. However, by the end of the experiment, the release of heavy metals during decomposition was observed for all elements.

Changes in the nitrogen isotopic composition during the transformation of peat-forming plant litter at dried and post-pyrogenic sites of oligotrophic bogs

The aim of the study. Assessment of changes in the nitrogen isotopic composition (δ15N) during the decomposition of the main peat-forming plants’ litter in peat of oligotrophic bog ecosystems in the southern taiga subzone of West Siberia. Location and time of the study. The studies were carried out in 2019–2021 in two oligotrophic bogs: “Bakcharskoye” (field station “Vasyuganye” (IMCES SB RAS)) and “Iksinskoye”, which are the north-eastern spurs of the Great Vasyugan mire and located in the Bakcharsky district of the Tomsk region, Russia. Methods. The decomposition rate of peat-forming plants’ litter was determined by the method of partially isolated samples, which is widely used to study the transformation of plant material and peat. The nitrogen isotopic composition in the original and decomposed samples of the plant material was determined by isotope ratio mass spectrometry using a DELTA V Advantage mass spectrometer combined with a Flash 2000 elemental analyzer (EA-IRMS). Results. A three-year study of the decomposition of peat-forming plants (Sphagnum fuscum, Chamaedaphne calyculata, Eriophorum vaginatum and a Mixed sample) in four ecosystems (natural - VASnat, drained - VASdry, post-pyrogenic - Iksa1 and Iksa2) showed that melioration and fire influenced the litter decomposition rate, increasing the latter in the drained bog and slowing down Sph. fuscum and Mixed sample decomposition by 1.5–9.0% at the site with pyrogenic effects. During the plant litter transformation carbon and nitrogen were released as 24–62% and 21–46%, respectively. In all studied samples, except for Sph. fuscum, a relationship was revealed between the plant litter mass loss and changes in the nitrogen isotopic composition. Conclusions. The effect of peat fires is manifested by a decrease in the plant residue decomposition rate. The dynamics of changes in the isotopic composition during the transformation of the studied plant residues depended on the plant species, but does not depend on decomposition duration (1, 2, 3 years) and sample location. Key words: transformation of plant residues; nitrogen isotopes; biogeochemical cycle; pyrogenic peatlands; drained peatlands; West Siberia.

Assessment of Greenhouse Gas Emissions into the Atmosphere from the Northern Peatlands Using the Wetland-DNDC Simulation Model: A Case Study of the Great Vasyugan Mire, Western Siberia

The peatlands of Western Siberia occupy an area of about 1 million km2 and act as important regulator of carbon exchange between the earth and the atmosphere. Extrapolation of the results of discrete field measurements of CO2 fluxes in bog ecosystems to such a territory is a difficult task, and one of the ways to overcome it is to use a simulation model such as DNDC. However, using this model with a specific territory requires ground verification to confirm its effectiveness. Here, we tested the DNDC model on the largest pristine bog ecosystem of the world, the Great Vasyugan Mire (GVM). The GVM of western Siberia is virtually undisturbed by anthropogenic activity and is the largest bog of Northern Eurasia (53,000 km2). Based on various ground-based observations, the performance of the Wetland-DNDC model was demonstrated (Thale coefficient 0.085 and R2 = 0.675 for CO2). Model input parameters specific to the GVM were constrained and model sensitivity to a wide range of input parameters was analyzed. The estimated annual terrestrial carbon fluxes in 2019 from the GVM test site are mainly controlled by plant respiration (61%) and forest floor degradation (38%). The net CO2 emission flux was 8600 kg C ha−1 year−1, which is in line with estimates from other independent studies.

Seasonal and Spatial Variations of Dissolved Organic Matter Biodegradation along the Aquatic Continuum in the Southern Taiga Bog Complex, Western Siberia

The inland aquatic ecosystems play a significant role in the global carbon cycle, owing to the metabolism of terrestrially derived organic matter as it moves through fluvial networks along the water continuum. During this transport, dissolved organic matter (DOM) is microbial processed and released into the atmosphere, but the degree and intensity of this processing vary greatly both spatially and temporally. The Western Siberian Lowlands is of particular interest for a quantitative assessment of DOM biodegradation potential because the global areal-scale effects of DOM biodegradation in abundant surface organic-rich waters might be the highest in this region. To this end, we collected water samples along a typical aquatic continuum of the Bakchar Bog (the north-eastern part of the Great Vasyugan Mire) and, following standardized protocol, conducted an experimental study aimed at characterizing the seasonal and spatial variability of dissolved organic carbon (DOC) biodegradability. The biodegradable DOC fraction (BDOC) over the exposure incubation period ranged from 2% to 25%. The natural aquatic continuum “mire–forest–stream–river” demonstrated the systematic evolution of biodegradable DOC among the sites and across the seasons. The highest biodegradation rates were measured during spring flood in May and decreased along the continuum. The maximum possible CO2 production from DOM yielded the maximum possible flux in the range of 0.1 and 0.2 g C-CO2 m−2 day−1 d, which is an order of magnitude lower than the actual net CO2 emissions from the inland waters of the WSL. This study suggests that although the biodegradation of the humic waters of the WSL can sizably modify the concentration and nature of the DOM along the aquatic continuum, it plays only a subordinary role in overall C emissions from the lakes and rivers of the region.

State Assessing and GIS Modeling of the Post-Pyrogenic Dynamics of the Great Vasyugan Mire Site

State Assessing and GIS Modeling of the Post-Pyrogenic Dynamics of the Great Vasyugan Mire Site

Effects of wildfire on the water chemistry of the northeastern part of the Great Vasyugan Mire (Western Siberia)

In this study, we determined the effect of wildfire in 2016 on the water chemistry of the northeastern drained part of the Great Vasyugan Mire. The influence of the pyrogenic factor on the water chemistry of the Great Vasyugan Mire was marked by an increase in concentrations of Na+, K+, Ca2+, Mg2+, Fetotal, SO4 2–, HCO3 –, NO– 3, Zn, Cu, Pb, and Cd. The maximum concentrations were observed in the spring (April) during the snow melting period, as well as during the rewetting period after the summer drought. In 2018–2019, there was a decrease in the concentration of the components in the waters after the fire in 2016 (SO4 2–, HCO3 –, NO– 3, Pb, Cd, Zn). An increase in the content of Na+, K+, Ca2+, Mg2+, NH+ 4, and Cu was noted, which is associated with the intensification of the processes of mineralisation of plant residues in the upper burnt peat layers.

Diurnal and seasonal dynamics of the electrical conductivity of water of the northeastern part of the Great Vasyugan Mire (Western Siberia)

In this study, we determined the diurnal and seasonal dynamics of the electrical conductivity of waters of the northeastern part of the Great Vasyugan Mire in Western Siberia. Our studies showed that the electrical conductivity of the waters for the period of April to September 2016 was characterised by a value of 35 μS/cm, and the seasonal amplitude was 25 μS/cm. In seasonal dynamics, there are three maximums of electrical conductivity in waters. The first maximum was formed in April (48 μS/cm) and is associated with snowmelt water supply. The second one was observed in May after the complete thawing of the peat deposit (39 μS/cm), and the third was observed at the end of July as a result of biochemical processes in the peat deposit (43 μS/cm). Our studies have shown the electrical conductivity hysteresis during time intervals from 3–5 to 6–10 days electrical conductivity remains constant despite the change in hydrometeorological conditions (water table level, temperature).

Post-fire composition of lipids in waters and plants of Great Vasyugan Mire

A lipid compositions were determined in water and plant samples taken in natural and burnt-out areas of the Bakchar bog (northeastern part of Great Vasyugan Mire) located in the basin of the Gavrilovka River within Tomsk region and were analyzed via gas chromatography-mass spectrometry. The following main groups of organic compounds have been identified: acyclic n-alkanes, fatty acids, and n-alkan-2-ones. Among cyclic compounds steroids, sesquiterpenoids, and pentacyclic triterpenoids have been identified. It was shown that lipids in waters contained biomolecules of plants grown in the areas under study. Chemical indicators reflecting the disappearance of plants since a fire and their restricted distribution or replacement of some plant species with others were found out. These indicators can be used in paleoclimatic reconstructions to fix post-pyrogenic layers in the sedimentary rock strata.

Drainage consequences and self-restoration of drained raised bogs in the south-eastern part of Western Siberia: Peat accumulation and vegetation dynamics

This study analysed the drainage influence on vegetation and peat deposit and assessed the self-restoration of ecological functions of Western Siberia bogs. As a case study, we selected four raised bogs – two are the east-northern spurs of the Great Vasyugan Mire and two are small, raised bogs on the terrace of the Bakchar River and the Ob River. The consequences of drainage and the ability to self-restore are influenced by the moisture conditions before drainage, bog size, distance between ditches and microtopography characteristics. The dominant species under wet conditions, such as Sphagnum magellanicum and Sphagnum balticum, changed with drainage to Sphagnum fuscum, and the peat accumulation rate increased. The sites with more dry conditions and dominated by Sphagnum fuscum were characterised by the intense degradation of Sphagnum, Bryidae and lichen growth and a low peat accumulation rate. Large raised bogs are relatively stable and capable of self-restoration. The drainage effect was more significant within some parts of the small bogs. Drainage consequences were less dramatic for large bogs, even in the marginal parts and near the ditches. A distance between ditches of 40 m and less is critical for self-restoration. Our study demonstrates that modern peat accumulation occurred in most parts of the plots; the mean peat accumulation rate over the last 35 years was 0.43 cm per year. Drainage influence in the south-eastern part of Western Siberia is less significant than in European bogs, not only because of the high stability of raised bogs but also because of the lower drainage intensity as well as the absence of forest planting, fertilisation and peat mining.

Great Vasyugan Mire: How the world's largest peatland helps addressing the world's largest problems.

Peatlands cover 3% of the land, occur in 169 countries, and have-by sequestering 600 Gt of carbon-cooled the global climate by 0.6°C. After a general review about peatlands worldwide, this paper describes the importance of the Great Vasyugan Mire and presents suggestions about its protection and future research. The World's largest peatland, the Great Vasyugan Mire in West-Siberia, forms the border between the Taiga and the Forest-Steppe biomes and harbours rare species and mire types and globally unique self-organizing patterns. Current oil and gas exploitation may arguably be largely phased out by 2050, which will pave the way for a stronger focus on the mire's role in buffering climate change, maintaining ecosystem diversity, and providing other ecosystem services. Relevant new research lines will benefit from the extensive data sets that earlier studies have gathered for other purposes. Its globally unique character as the 'largest life form on land' qualifies the Great Vasyugan Mire in its entirety to be designated as a UNESCO World Heritage Site and a Ramsar Wetland of International Importance.

Monitoring the Atmospheric Deposition of Zn, Cu, Cd, and Pb within the Area of the Great Vasyugan Mire

This study presents the results of an assessment of the pyrogenic factor’s contribution to atmospheric pollution in territories of the Tomsk region, based on the analysis of heavy metal (Zn, Pb, Cu, and Cd) atmospheric deposition within the Bakchar Bog (the north-eastern part of the Great Vasyugan mire). Atmospheric depositions of Cu, Pb, Zn, and Cd were analysed using the passive dust deposition method, measuring particle content per m2 during 2018–2019. Data analysis showed an excess of Zn in atmospheric deposition that persisted for three years after a fire in a drained bog, during both summer and winter observation periods, with a maximum value of 3.63 mg/m2 per month in 2018. The impact of the fire on Cd and Pb content persisted for two years after the fire. The Cu content of atmospheric depositions is not affected by the pyrogenic factor. The analysis of seasonal dynamics showed that the Zn, Cd, and Pb content of atmospheric depositions was influenced by wild fires that cause the transfer of pollutants at both local and regional scales.

New artificial network model to estimate biological activity of peat humic acids

PurposeThis article focuses on new method to estimate biological activity of peat humic acids (HAs) using artificial neural network (ANN) to process spectroscopic measurements in infrared and visible ranges. Conventional approaches generally rely on biological models and direct detection of chemical substances related to bioactivity. These methods proved to be accurate and reliable, but at the expense of speed and simplicity. Materials and methodsRecently, a conception of quantitative structure-activity relationship (QSAR) has been introduced and successfully implemented to predict effects of HAs on toxicity of polycyclic aromatic hydrocarbons. Our research stems from this conception, but employs multilayer perceptron (MLP) model to improve overall performance. The developed MLP model allowed us to estimate biological activity of the complete vertical peat cores collected from oligotrophic peat bog, located in southern taiga zone of West Siberia (north-eastern spurs of the Great Vasyugan Mire, 56°58′ N 82о36’ E). In total, 42 samples taken from the cores were collected. The protocol included spectroscopy (in infrared and visible ranges) and biological model with peritoneal activated macrophages as a reference method to directly measure biological activity of HAs. Resultsand discussion. Numerical experiments confirmed consistency of the measured and estimated bioactivity, coefficient of determination R2 = 0.97. These experiments also showed that the MLP model significantly outperforms conventional linear multiple regression models, mainly due to essential nonlinearity of structure-activity relationships. ConclusionsOur research demonstrates that biological activity of HAs extracted from peat samples can be estimated using an artificial neural network model trained on infrared and visible spectra.

Assessing mire-river interaction in a pristine Siberian bog-dominated watershed – Case study of a part of the Great Vasyugan Mire, Russia

Siberian mires, especially the world’s largest coherent bogs of the Great Vasyugan Mire (Tomsk Region, West Siberian Plain, Russia), play an important role in the regional hydrological cycle, global carbon balance and influence flow formation of the region’s rivers. We revealed the role of natural mires in supplying water to a mire-dominated (80% of the river basin area) Siberian catchment of the Klyuch River that represents typical features of the headwater catchment of the Great Vasyugan Mire, the world’s largest mire in natural and well-preserved conditions. Our research protocol involved an analysis of the electric conductivity of peat water along selected transects of the mire, analysis of groundwater levels and river discharge and electric conductivity of the river water. We used ground-penetrating radar to determine the structure of the peat. We revealed that the examined part of the mire depends solely on the rainwater supply and that minerotrophic groundwater is not present within the area of the research. Average groundwater levels within the mire in the period 2013–2018 reached 0.193 m b.g.l. We also revealed that the natural drainage of mire water does not sustain river discharge throughout the whole year. This means the Klyuch remains an intermittent river dependent on the natural outflow of the mire’s waters, after exceeding the mire’s critical water retention volume. Total retention volume of a mire depends on the peat’s physical features and the mire’s short-term response to excessive thaw and precipitation events. An analysis of river discharge duration curves demonstrated that river discharge can be sustained by the duration reaching from 0.39 up to 0.71 in a year, in dry and wet years, respectively. We concluded that in a specific hydrogeological setup of the mire–river system, natural ombrotrophic mires cannot be considered as systems with a continuous water supply and discharge stabilization. We concluded that the Hortonian vision of infiltration and discharge is not valid in bog dominated basins. In the face of climatic changes in Siberia, we foresee a decrease in the discharge volume from the headwaters of rivers and the increase of river intermittence which may affect total outflow volume, specifically in the upper Ob and Irtysh, by reducing the contribution of surface runoff.