Annotation of the results obtained in 2020
In the process of implementing the project in 2020, extrapolation of the results obtained in 2018 - 2020 was carried out to the territory of the study area of the Ob basin and its floodplain. Observation data for temperature, transparency, pH, electrical conductivity, dissolved oxygen in dynamics in the main phases of the water regime for the period in 2018 - 2020 are systematized and summarized. The conductivity hardly changes in different seasons. The concentrations of dissolved oxygen and carbon dioxide change significantly in different seasons: in spring, the water of floodplain lakes is intensively diluted with melt snow water, and is also actively saturated with oxygen from the atmosphere. Photosynthesis processes are active in summer. In autumn, when aquatic organisms die off or become less active, photosynthesis may still be high, and dissolved O2 concentrations rise when dissolved CO2 levels are low. With the onset of freeze-up, the accumulation of dissolved CO2 in water begins. Oxygen consumption by aquatic organisms continues, however, due to the lack of photosynthesis and influx from the atmosphere, the concentration of dissolved O2 decreases during the winter and can reach zero at the end of freeze-up. Dissolved CO2 concentrations for the same period reach an annual maximum. In spring, CO2 concentrations drop sharply. In all seasons, the aquatic environment is slightly alkaline; in winter, some pH values are equal or below 7. The highest pH values were recorded in summer and autumn. The transparency indices during the season in rivers also do not differ significantly and do not have any regularities depending on the hydrological season. The data on the intensity of CO2 and methane fluxes by the chamber method in different water bodies in the main phases of the water regime in 2018-2020 have been systematized and generalized. Analysis of the 2018 - 2020 data showed unexpectedly low C emissions with a downward trend in C at the beginning of the flood, while the channel was at the same time a stronger source of C to the atmosphere. At the beginning of the flood, it was assumed that the influence of the channel on the floodplain would be strongest when the exchange of water between the channel and the floodplain was greatest, and this should lead to higher inflows of C from the stagnant waters of the floodplain. However, this trend has not been observed. This indicates a strong dilution effect with large inflows of water reaching the floodplain, as well as additional inflows of melt water from the surrounding landscape. After the end of the flood and with the onset of summer baseline conditions, the role of the floodplain becomes more important with higher DOC and DIC concentrations and higher flow rates (Table 5-2). With the onset of summer conditions, the role of the floodplain becomes more important at higher concentrations of DOC and DIC, as well as generally higher flow rates of C. An increase in temperature (water: 20 ± 2 ° C, air: 24 ± 2 ° C) leads to intensification of processes destruction in the river and in flooded soils and contributes to an increase in CO2 emissions from the water surface into the atmosphere. Additionally, the mapping of FCO2 flows in the floodplain of the Obi during the 2020 flood. Despite the short duration of the connection of the floodplain with the main river channel, the floodplain is a powerful source of C in the atmosphere, the value of which varies depending on the season. Snow survey and sampling for the analysis of the isotopic composition of the snow cover in 2020 was carried out in the same way as in previous years in the first ten days of March. After the snow survey, the hydrological characteristics were calculated: surface runoff module; runoff layer, runoff volume. Extrapolation of the results of snow survey 2018 - 2020 on the territory under study was carried out on the basis of a generalized landscape-geochemical digital cartographic model. Systematization and generalization of the results of chemical and analytical studies of samples taken in 2018, 2019 and 2020 was carried out. The main task of data systematization was the binding of the obtained data to the cartographic material in order to extrapolate them to areal objects. All hydrometric data (hydrological regime and water balance of streams, swamps and lakes) were generalized, and a hydrological balance model was constructed for the watersheds and floodplains of the Middle Ob. Identification signs of runoff from various catchments of rivers and floodplain water bodies were revealed. The ratios DIC / Na, DIC / Al, DIC / Si, DIC / U can be used as indicative signs for different purposes. For the identification of water bodies, the most reliable indicators are the DIC / U ratio, the second most important is DIC / Si. The DIC / U ratio made it possible with a high degree of reliability (0.95) to separate floodplain water bodies and tributaries of the Ob from the main channel of the Ob. The assessment of the spatio-temporal variation of the isotopic composition and organic matter of river waters under the influence of floodplain processes was carried out. When studying the dynamics of the isotopic composition of precipitation, it was found that the lowest concentrations of δ18O and δ2H are characteristic for winter precipitation, and the highest for winter. A significant range of variations in the isotopic composition of water in floodplain water bodies and watercourses was revealed. River waters have a lighter isotopic composition than lake waters. The waters of the Ob tributaries are lighter than the waters of the main channel. The isotopic composition is also an identification feature of the tributaries of the river. Ob. A model was created for the contribution of the floodplain to the total export of organic carbon to the Ob. The model is built on the basis of the balance of the amount of water supplied from the Ob channel with the known content of organic carbon, chemical elements and the area of flooding of different floodplain landscapes by flood waters, the residence time of flood waters on the territory of different floodplain landscapes, taking into account the received atmospheric precipitation, evaporation from the flooded area and the amount of floodplain released waters from the floodplain into the main channel of the river. Obi. An important element of the model is the residence time of flood waters on the territory of the floodplain. At this moment, the flood waters are saturated with organic matter and dissolved carbon, and powerful flows of CO2 are noted on the flooded floodplain into the atmosphere. The data obtained make it possible to differentially calculate the flows for each landscape of the floodplain, as well as to calculate the amount of water that left these landscapes into the Ob channel. The model makes it possible to predict flows at different levels of floodplain flooding and to carry out their retrospective analysis. An identification model based on data on the composition and structure of organic matter is proposed. It is intended to clarify the migration of flood waters in the floodplain during the period of maximum flood and the hydraulic connection of landscapes during the flooding period. The model made it possible to identify the main transit flows of flood waters in the floodplain with a short residence time of water in landscapes. In these parts of the floodplain, the least accumulation of dissolved carbon in water occurs and less CO2 fluxes into the atmosphere are noted. This model makes it possible to get closer to understanding the hydraulic interaction of floodplain landscapes with floodplain water bodies after the descent of flood waters and further transformation of organic matter in water bodies. A generalized landscape-geochemical digital cartographic model has been created, which contains qualitative and quantitative information on the main flows of organic carbon and metals in the floodplain, adjacent territories and flows from the floodplain, which affect the geochemical sink of carbon and metals into the river channel. Obi. For the landscape-geochemical cartographic model, the Ob-GIS geographic information system was used, which includes a database of thematic maps, satellite images, a relief model and a grid of runoff lines. Attribute information is attached to the graphic information, which is the results of instrumental measurements of dissolved carbon, FCO2 fluxes into the atmosphere, the studied chemical elements and the results of the study of organic matter in water bodies during the spring flood. The cartographic model allows the area assessment of organic carbon, chemical elements and their fluxes in the floodplain, tributaries and main channel of the river. Obi. The model provides an additional opportunity in modeling and studying the mechanisms of formation of geochemical runoff from the floodplain territory. Map layers and attribute information are stored in the ArcGIS personal geodatabase (MDB) format. The project is available at https://www.researchgate.net/profile/Sergey_Vorobyev2/research?ev=prf_act.

 

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Annotation of the results obtained in 2018
Western Siberia is the most important supplier of carbon and other chemical elements to the atmosphere and the Arctic Ocean. An important role in this process belongs to small tributaries and the Ob floodplain. Their feature is the anomalous enrichment of DOC, CO2 and metals, which can be 10 times more than in the beds of large rivers. At the same time, it has been established that the flow of CO2 emissions from the surface of open water to the atmosphere may exceed the lateral export of carbon by rivers. The fundamental scientific task is to assess the removal of dissolved CO2 with river waters, CO2 emissions from the surface of open water into the atmosphere to identify the relationship between hydrochemical and gas regimes in a large river (using the Ob river as an example) and its small tributaries. Large rivers have some features that distinguish them from small rivers. In the middle course of the Ob, there is a significant, more than 10 times, concentration gradient of DOC, CO2 and some metals between small tributaries and the main channel. The aim of the project is to establish the relationship between the hydrochemical and gas regime in the Ob and its tributaries: small rivers as the main suppliers of untransformed organic matter, nutrients, metal-organic complexes and colloids in the Ob. The first year of the project is more organizational and involves working with stock and literary materials, as well as a preliminary synthesis of our own materials we received earlier on r. Ob, r.Yenisey and their watersheds. As a result of the project, free-access fund and literary materials about the Ob floodplain were summarized. The Ob-GIS geoinformation system was developed for collecting, storing and analyzing materials obtained during the project. Working cartographic materials were produced, space imagery materials were obtained and their primary processing was carried out, hydrological and meteorological data were compiled (1959-1975, 2013-2018). Soil-geobotanical, hydrochemical maps, temperature differentiation maps of landscapes of the floodplain of the Middle Ob were compiled according to large-scale infrared surveys on the scale of M 1: 5000, M 1: 50,000, M 1: 200,000. The analysis of long-term meteorological data during the execution of the project has revealed some local climate features in the study area. The archived data of soil temperature and humidity of the studied territory at our disposal allowed us to divide the alluvial soils of different parts of the floodplain into main groups according to the nature of the hydrothermal regimes and their seasonal changes. In the course of the work, key areas were substantiated and fixed on the ground for future stationary work on the watersheds and in the floodplain, their instrumental geodetic survey was carried out. Preliminary maps of marshes, vegetation, soils, quaternary sediments, surface water migration flows are made on key sites. High-resolution aerial photography was carried out in the optical and infrared ranges using an unmanned aerial vehicle, and the temperature differentiation of water bodies and marshy and dry-ground landscapes was evaluated. It is revealed that thermal imaging is most effective at low altitudes and at night. At this time, the temperature of the underlying surface is well diagnosed. In the daytime, it prevents the diagnosis of vegetation. The temperature of the vegetation is much higher and it blocks the radiation from the underlying surface. Image analysis and thematic interpretation of multi-temporal space images were carried out. Materials obtained from snow surveying in key areas, during the period of maximum snow cover, the composition of stable isotopes D-H and O-18 in snow, floodplain water bodies and in the Ob River is determined. The results showed the promise of using data on stable isotopes to identify water sources in the floodplain. Water samples were taken in the Ob River at its most typical sites, tributaries, floodplain water bodies, surface water and groundwater, samples of bottom sediments and soil. The samples were prepared for the study of organic matter, general hydrochemical, geochemical analysis and determination of stable isotopes DH and O-18 in water. The data on electrical conductivity, pH, dissolved CO2, O2 in water bodies were obtained: the Ob in its most typical areas, tributaries, floodplain water bodies, swamp waters, surface water and groundwater. New hydrological and hydrochemical data on the tributaries of the Ob River and its floodplain bodies of water were obtained, monitoring of the river flow from the marshy watersheds was conducted. The data on the chemical composition (C, N, micro- and macroelements) of marsh waters, river and floodplain waters in the dynamics of the main phases of the water regime, bottom sediments were obtained. Observing the chemical flow of river, lake and marsh waters, two contrasting seasons were taken into account, the spring flood and summer low flow stock. Observations on these seasons made it possible to identify elements that are controlled by groundwater inflow (DIC, Na, Mg, Ca, SO4, Sr, Mo, Sb, and U) and elements that are controlled by surface runoff formed during the decomposition of plant litter and leaching of topsoil , especially during the spring flood (Si, K, Rb, Mn, Zn, and Cu). At the same time, Cl, Zn, Cd, Sb, Cs and Pb in lakes and flood lakes in May may be significantly affected by aerosol deposition (snow melting). During the flood in Ob, the dissolved chemical composition of the stream can be approximated within ± 30-40% to the chemical composition of the flooded area - lake and marsh waters. New data on electrical conductivity, pH, dissolved CO2, and O2 in water bodies have been obtained: the Ob in its most typical areas, tributaries, floodplain water bodies, swamp waters, surface water and groundwater. High variability of all measured parameters in floodplain reservoirs in different seasons was revealed. There is a variability of these parameters in the Ob, but compared to the floodplain water bodies, it can be considered insignificant. Direct instrumental measurements in water bodies and landscapes have shown a high differentiation of water bodies and marshy floodplain landscapes by measured values. The highest value of dissolved O2 is characteristic of the flood period in all landscapes. In the low summer period, the content of dissolved O2 in the Ob River remained almost unchanged, and decreased in floodplain reservoirs. In marshy landscapes, the O2 value also decreased. Daily fluctuations of O2 in floodplain reservoirs and marshy landscapes are revealed. During the nighttime period, the O2 value decreases on average by 10%, and increases during the daytime. Such a pattern of O2 change is associated with the phases of photosynthesis. In the daytime, in the light phase of photosynthesis, an increase in O2 occurs, in the nighttime, in the dark phase of photosynthesis, plants absorb O2 and release CO2, due to plant respiration. At night, CO2 in water bodies increases, during daytime it decreases. In the Ob River, daily fluctuations between night and daytime have not been identified, this is due to the high heterogeneity of the channel flows in the river. The intensity of CO2 and methane fluxes in different water bodies was estimated, the CO2 fluxes from different landscapes were estimated by the chamber method. For the first time, data were obtained on the intensity of CO2 fluxes of floodplain objects of the Ob into the atmosphere. Preliminary results showed a significant difference between the phases - the minimum flows are characteristic for the maximum flood, the maximum flows for low days. In floodplain swamps and marshy landscapes, flows in different phases differ by more than 3 times. As shown by the results of measuring the flow of CO2 into the atmosphere by the chamber method, landscapes of the floodplains and water bodies differ significantly in terms of CO2 emissions in different seasons of the year. The least results are typical for the Ob River. In the tributaries of the Ob, the discharge of which is formed on the marshy watersheds, the emission value is much higher and reaches 500 ppm per hour. The greatest streams are characteristic of swampy landscapes of the floodplain. Sogra (marshy birch forest) makes the greatest contribution to the flow of CO2 to the atmosphere (8850 ppm per hour, floodplain bog 4675 ppm per hour), marshy meadow 2872 ppm per hour. marshy landscapes contain the highest concentration of dissolved CO2 - more than 30,000 ppm. The CO2 emission data from the floodplain landscapes were obtained for the first time and indicate the significant role of the floodplain. The data on the botanical composition of peat and the degree of its decomposition, the chemical characteristics of peat throughout the depth of the peat deposits of the main types of wetlands in watershed areas and floodplains and new information on the composition and structure of organic matter in the most typical floodplain water bodies were obtained. There are no floodplains in the studied area, peat columns collected from the catchment areas of the Ob tributaries co-occur from high-moor peat biologically inert with a high absorption capacity and adsorption capacity. The main peat generator is the slightly decomposed sphagnum fuscum. In the structure of the peat deposit there are many inclusions of intermediate residues of pine and other woody residues. The structure of organic matter is dominated by fulvic acids and a small amount of humic acids. Judging by the composition of peat, the marsh food is mainly atmospheric. Signs of peat formed with the participation of groundwater in the investigated area was not found. For the first time, data were obtained on the chemical composition of 39 samples of swamp waters, river and floodplain waters in dynamics during the main phases of the water regime, bottom sediments. The following elements are defined in each sample: Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As , Rb, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb , Lu, Hf, Ta, W, Tl, Pb, Th, U. Analyzes of organic matter and its structure, characteristics of humic acids (elemental composition, carbon fraction of aliphatic and aromatic groups) were carried out. Quantitative comparisons of the degree of aromaticity of HA macromolecules were carried out. In general, the electronic absorption spectra of humic acids of the studied water have the form of gentle curves, decreasing with a wavelength characterized by monotonicity. For many HAs, the proportion of carbon represented by aromatic structures is directly proportional to the extinction coefficient at a wavelength of 465 nm. This allows in the first approximation to estimate the degree of aromaticity and the relative stability of humic substances by E-values. In general, the results of the project have received a very large amount of materials that require further analysis and synthesis.

 

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Annotation of the results obtained in 2019
Study of the biogeochemical properties of the Ob River, small rivers and floodplain lakes were conducted in the middle reaches of the Ob, in the area of the Kaybasovo research station (Tomsk State University). Data were obtained on the migration of organic matter in the floodplain during the flood period using large-scale shooting in the optical and infrared ranges from unmanned aerial vehicles. To capture the dynamics of the water surface of watersheds and floodplains, a quadrocopter and a deltalet were used. The flight results showed that the images in the optical range give sharp, contrasting boundaries for mixing the Ob and the flooded floodplain. To compile thermograms of the floodplain, thermal imaging from a deltalet was used. In the course of the project, data were obtained for the first time on the intensities of gas flows of CO2 and CH4 by the chamber method in different water bodies of the middle Ob floodplain during the main phases of the water regime. The average CO2 fluxes in the Ob channel (4 ± 5.1 g C m2) were higher than in floodplain water bodies (1.1 ± 3.2 g C m2). On the contrary, average CH4 fluxes were slightly lower in the Ob channel (0.02 ± 0.02 g C m2) (0.02 ± 0.02 g C m2) compared to the floodplain. CO2 and CH4 fluxes showed seasonal differences with a maximum in summer for the Ob channel (CO2: from 4.6 ± 4.1 g C m2 in May to 8 g C m2 in June; CH4: 0.014 g C m2 in May), and also for the floodplain (from 0.02 ± 1.7 g C m2 in May to 8.9 ± 6.3 g C m2 in July; CH4: from 0.03 ± 0.02 g C m2 in May to 0.09 ± 0.02 g C m2 in July). It was revealed that in a dry year the total annual emission of the Ob was 5 times greater than that of floodplain water bodies. Interestingly, the floodplain showed very low carbon emissions with a tendency to decrease it at the beginning of the flood. The Ob channel, at the same time, was a constant source of carbon into the atmosphere. This indicates a strong dilution effect with large inflows of water reaching the floodplain, as well as additional meltwater inflows from the surrounding landscape. With the onset of summer baseline conditions, the role of the floodplain becomes more important. Having lost almost half of the water cover, the floodplain loses direct connection with the main river bed and becomes quite isolated. At the same time, an increase in temperature can lead to increased decomposition of organic matter in the river and, probably, contributes to higher flow rates from the surface of the water to the atmosphere. In the low flood year, the contribution of the floodplain to the net СО2 emission was relatively low; the floodplain was practically not flooded. However, it is possible that the floodplain may be of greater importance in more extreme flood years, when large areas are flooded. However, it is obvious that ignoring flood C emissions under such extreme flooding conditions can lead to errors in calculating river C budgets and may underestimate the total volume of river C emissions, especially in those regions where there are no large-scale measurements of flood C flood. Data were obtained on the content, composition and structure of the organic matter of the Ob River, small rivers and floodplain water bodies. It was established that in the area of ​​the Kaybasovo hospital in the Ob, the maximum amount of dissolved inorganic carbon (RNU) falls at the beginning of spring, while in the waters of small rivers its amount decreases at that time, and the peak falls at the end of summer. The content of dissolved organic carbon (DOC) of small rivers exceeds its content in the Ob, and its maximum content in small rivers was noted in the month of July, during the summer low water period. In floodplain water bodies, the content of DOC is comparable to that in small rivers, and in winter low water it is higher than in flood. The content of RNU in the Ob is on average higher than in small rivers. The content of DOC, in contrast, in small rivers is much higher than in the Ob and its maximum amount in small rivers was noted during the summer low water period. In Ob, the content of RNU practically does not change throughout the season. The methane content decreases with the transition from floodplain water bodies to the main river, the oxygen content increases. The concentration of dissolved CO2 in the Ob is much less than in lakes, but in small rivers more than in lakes. For oxygen, an inverse distribution is observed. During floods, the difference in the content of substances in different types of water bodies is less significant. The Ob River is characterized by a heterogeneous content of dissolved CO2 and O2 throughout the year, while patterns in the daily dynamics of O2 and CO2 are not observed. In the Ob River, throughout the year, the SUVA254 indicator is <3, which indicates the predominance of hydrophilic material and low molecular weight aliphatic compounds in the composition of dissolved organic matter both in low water and in high water. In small rivers, the aromaticity and hydrophobicity of organic matter is much higher than in the Ob, especially during floods, in lakes, on the contrary, in winter, the aromaticity and hydrophobicity of organic substances increases. For natural waters of the studied region, the values ​​of the coefficient E254: E436 ranged from 39.6 to 13.4, which indicates a high content of autochthonous organic matter in the composition of dissolved organic. During the winter low water season, the Ob waters are richer in autochthonous organic matter than in the spring flood, in small rivers and lakes the percentage of allochthonous matter is higher than in the Ob. The maximum differences in the composition of the organic matter of the Ob and small rivers occur in the autumn and winter months, during the flood period, the coefficients of different types of objects are closest to each other. For the first time, our project obtained data on the basis of NMR spectraconcerning the structure of organic matter in water bodies, bottom sediments, in peat and soil of the watersheds and floodplain in the middle ranges of the Ob. It was established that the structures of peat, bottom sediments and soils are different: the content of carbon radicals in bottom sediments is lower in comparison to peat and soil. The structure of all the studied samples is represented by short-chain organic acids up to C10. We obtained data on the size of molecules, the content of aromatic fragments, and the degree of humification of organic substances. It was established that in small rivers the hydrophobicity of organic matter is higher than in the Ob, especially during the flooding, and the degree of benzoidity increases during the flooding. The maximum differences in the composition of the organic matter in the Ob and small rivers occur in the autumn and winter months. During the flood period, the coefficients of different types of objects are closest to each other. A number of properties of water bodies were determined in situ in the course of the year. Based on the measurements, it was found out that parameters varied significantly depending on the season. The maximum concentration of dissolved oxygen and the minimum dissolved carbon dioxide were noted during the flooding and the minimum content of dissolved oxygen in the winter low-water period. In the winter, the oxygen content of the lakes was zero. Snow surveys were carried out at key sites, snow cover samples were taken to determine snow reserves and isotopic composition of water before snow melting. The obtained data was compared with the values from previous years. It was established that the volume of snow, excluding losses due to evaporation and infiltration, was only 5% lower in comparison to 2018 For the first time, with synchronous measurements, we obtained data concerning the isotopic composition of the groundwater, the floodplain soil-groundwater, the floodplain water bodies and the Ob and small rivers in the course of the year. It was established that the most stable composition of d18O-H2O is characteristic for the soil and groundwater and the Ob River. Interestingly, in the floodplain stream flowing along the main floodplain landscapes and reflecting the integral geochemical processes of the entire floodplain, there is a sharp surge in the increase of the d18O-H2O value during the formation of the ice cover and active freezing of soils. An increase in the d18O-H2O for small rivers was also noted during this period, but it was less significant. In the groundwater, soil-groundwater and the Ob River, such changes were not discovered. The d18O values in the snow ranged from -26.27 ‰ to -16.41 ‰. The maximum values of d18O and d2H were characteristic for the spring period corresponding to the onset of snowmelt. It should be noted that in the summer period, the values of d18O d2H were maximum and amounted to -12.71 ‰ and -90.43 ‰, respectively. The values of d2H vary from -197.47 ‰ to -118.89 ‰. The local meteorite line (LMWL) does not differ significantly from the global line (GMWL) and generally corresponds to the latitude of the terrain, as shown by the LMWL equation: 2dH = 8.1531 * d18O + 19.738. One of the results of the second stage of the project has been updating and filling in the Geoinformational analytical system. According to the results of gained in 2019, the system has been complemented with new layers of data: a) a relief diagram, b) a diagram of hydrodynamic grids of runoff lines, c) a diagram of temperature fields. Maps have been made more detailed based on the new data decrypting materials of remote sensing, including infrared survey data and 2019 field research materials. A remote access to the system through the Internet has been organized.

 

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