Ob Floodplain Research Articles

Biota of floodplain lakes of the Ob river in the lower reaches of the Novosibirsk hydroelectric power station

An overview of typical lakes of the floodplain system of the river is presented. Ob in the lower reaches of the Novosibirsk hydroelectric power station, data on the species structure and biomass of fish, zoobenthos and zooplankton are presented. Most lakes of the Ob floodplain have an elongated channel-like shape and have a constant hydrological connection with the channels of the Ob River. The area of the lakes does not exceed 40 hectares. According to the research results, the zooplankton of the lakes is represented by 20 species, the total number of zooplankton varied from 50 620 copies/m3 (Kolkhoznoye lake) to 477 740 copies/m3 (Bolshoy Elbak lake). The biomass of zooplankton in the surveyed lakes was 2488–3443 mg/ m3. 24 species were found in the zoobenthos of floodplain lakes, the total number of zoobenthos varied from 887 copies/m2 (Kolkhoznoye lake) to 3468 copies/m2 (Bolshoy Elbak Lake). The biomass of zoobenthos varied from 3,100 to 38,152 g/m2. According to the indicators of zooplankton biomass, lakes are characterized as reservoirs of beta-mesotrophic type, i.e. of the middle productivity class, according to the classification of feeding capacity — as reservoirs above the average feeding capacity for planktophagous fish. On the development of zoobenthos lake. Vilannoe refers to high–fed, eutrophic type reservoirs, high productivity class, Kolkhoznoye lake — to medium-fed, mesotrophic type reservoirs, moderate productivity class, Bolshoy Elbak lake refers to high-fed reservoirs of mesotrophic type of medium productivity class. The main species of ichthyofauna of floodplain lakes are the firebrand rotan (Perccottus glenii) and silver carp (Carassius gibelio). The biomass of the ichthyofauna is 45.1–100.9 kg/ha. As a result of the study, it was revealed that commercial development of the ichthyofauna of these lakes is impractical, but their use for commercial fish farming is possible.

Long-Term Dynamics of the Avifauna in the North of Western Siberia

Changes in the avifauna of the three large regions of the north of the Yamalo-Nenets Autonomous Okrug (Russia), the Lower Ob River region, the floodplain of the Lower Ob, and the Yamal Peninsula, have been analyzed for a period of more than 60 years. The analysis is based on relative estimates of the number of species on a 4-point scale; cases of significant shifts in the species ranges also have been considered. It is shown that avifaunae in the long term are highly dynamic formations, the process of their changes is of a permanent nature. Its scale is about half of the species composition for 60 years and its directions vary greatly in different regions, depending on the degree of anthropogenic transformation of the territory. Areas with a relatively low anthropogenic impact (the Lower Ob and the Ob floodplain) are characterized by the predominance of the positive trends, mainly expressed in the appearance of new species. Many of them (more than 25% of the modern species composition) have been detected in the Ob floodplain, which indicates the canalization of the penetration process for new species to the north. The Yamal Peninsula region, where the anthropogenic impact associated with domestic reindeer overgrazing is high, is characterized by the predominance of the negative trends in the form of a decrease in the number of typical tundra species.

ПОСЕЛЕНИЕ ЕЛУНИНСКОЙ АРХЕОЛОГИЧЕСКОЙ КУЛЬТУРЫ В ПОЙМЕ ОБИ У С. КИПРИНО (АЛТАЙСКИЙ КРАЙ)

Near the village Kiprino in Shelabolikhinskiy district of Altai Krai a series of archaeological objects has been revealed. The main part of these sites is located in the Ob floodplain on the territory of the upland, which was formed during the erosion of the left bank of the river. This earthwork is called “Kiprinsky Borok”. By now, 10 places have been marked on its southwestern edge and in its immediate vicinity, where lifting material was collected after permanent destruction associated with natural and climatic and anthropogenic influences. Cultural layers are found in the blowout and bluffs. In one of such places, conditionally designated “Blowout №5”, fragments from the ceramic ware which analogies can be easily found among materials from settlement and burial sites of the Forest-steppe Altai Elunino archaeological culture of the early Bronze Age were found.

АРХЕОЛОГИЧЕСКИЙ МИКРОРАЙОН МАЛАЯ РЕЧКА: ПОСЕЛЕНИЕ КАЛИНИНО-I

The article is devoted to the substantiation of the allocation of two archaeological microdistricts located in the floodplain zone of the right bank of the Ob river in the vicinity of Barnaul and characterization of their geographical features. These complexes - microdistricts of the channels of the Zalomnaya and Malaya Rechka - are associated, first of all, with the presence of such a characteristic phenomenon of the Ob floodplain as the remnants of the right bedrock and floodplain sand dunes. These formations are usually confined to the system of water floodplain structures - channels, oxbow lakes, oxbow and spring lakes, as well as small rivers. The saturation of this territory with biological and mineral resources has attracted people here since the Stone Age. It is to the end of this era that the settlement of Kalinino I, located on the protruding cape of the indigenous right bank, belongs.

Dynamics of the aboveground phytomass of the Ob floodplain meadows in the area of the Tomsk carbon polygon (Kaibasovo)

At the Kaibasovo site (Tomsk carbon polygon), during 2017-2021, studies of multi-year changes in the vegetation of the floodplain meadows of the Ob river were carried out on 4 permanent sample plots to determine the effect of weather conditions and floods on the formation of aboveground phytomass.
 The research area is located within the southern taiga subzone of the forest zone and belongs to the northern part of the Shegarsky section of the floodplain. Permanent sample plots were laid out on relief elements of different flooding conditions - high ridges, their slopes, and depressions. Grass, forb and sedge phytocenoses were studied. In the phase of maximum development of the herbage, geobotanical descriptions and sampling of aboveground phytomass (including litter and rags) were carried out. Descriptions were made on an area of 100 m2, the herbage was mowed from squares of 0.25 m2 four times. Under field conditions, the mowing was sorted by types, dried and weighed. The productivity of the herbage was determined by summing up the masses of particular types. Further, the average indicators of phytocenosis such as the composition of dominant species, the total number of species, the composition and ratio of various fractions (agrobiological and ecological groups) were determined in terms of 1 m2 of aboveground mass.
 Weather conditions and meadow flooding regime for the growing seasons of 2017-2021 were characterized on the basis of data from the Molchanovo meteorological station and the Nikolskoe gauging station. We took into account the average ten-day and monthly values of temperature and precipitation as well as HTC for the entire growing season. This provided the possibility to select wet and dry, warm and relatively cold seasons as a basis for analyzing the phytomass dynamics. Based on the results of a general evaluation of hydroclimatic conditions, 2017-2018 have been assessed as warm, humid, mid-water, 2019 - extremely dry and hot, when the floodplain was not flooded, 2020 - slightly dry mid-water, 2021 - cold and dry with a relatively high flood.
 It was found that the dynamics of the meadow vegetation of the Kaibasovskiy section of the Ob floodplain is determined by the influence of the weather conditions of the current and previous years, the nature of the flood, and characterized by changes in the above-ground mass, the ratio of dominant species, the composition of ecological and biological groups of species in the herbage.
 The change in the state of the cereal community, developed on a high ridge, was due to the dynamics of weather conditions. The range of productivity changes over the years was the smallest. This was due to the good adaptability of the phytocenosis provided by a variety of vegetatively mobile long-rhizome grasses from the ecological groups of xeromesophytes, mesophytes and eumesophytes. The state of the other three communities studied was determined not only by weather conditions, but also by a more important factor such as flooding of meadows during seasonal floods. Their productivity turned out to be generally higher and the range of fluctuations in the amount of aboveground phytomass over the years was wider (on average, twice).
 The study of the relationship between the productivity of the herbage and the destruction of the aboveground part of the mortmass and hydroclimatic conditions showed that at all altitudinal levels of the floodplain in arid conditions, there is a decrease in the mass of the herbage of meadows and the accumulation of dead plant residues. The aboveground phytomass of the communities of the upper and middle altitude levels increases with the increase in environmental humidity, while the total aboveground mass increases, but the proportion of dead plant matter decreases.
 The increase of aboveground phytomass of sedge phytocenoses of medium-low and low levels occurs in humid, warm, mid-water years, while an increase in the abundance of moisture-loving grasses and sedges in the herbage is observed. The accumulation of the amount of dead plant matter is also observed in years with prolonged stagnation of water. The decomposition of litter and rags is most active in humid and warm spring.

Land-Use Changes on Ob River Floodplain (Western Siberia, Russia) in Context of Natural and Social Changes over Past 200 Years

Over the past century, substantial changes in land use have taken place in the boreal zone of northern Eurasia. The consequences of these large-scale changes for the ecosystems of Europe have been well studied; however, they have not been addressed for the large expanses of Russia. We conducted a retrospective analysis of the landscape dynamics of the middle reaches of the Ob floodplain (Western Siberia) using multitemporal maps of the vegetation cover and land use for five time points (1830, 1910, 1950, 1976, and 2019). By the 1830s, all the land that was suitable for haymaking and plowing (rarely flooded and not swamped) had been put to agricultural use. The meadows of the Ob floodplain are human-controlled and were mainly formed before the 1830s. From the 1830s to the 1990s, the meadows were used in agriculture and their areas increased. The maximum development of the floodplain occurred in the 1970s and 1980s, when previous wetlands were put into operation through the construction of drainage systems. A massive abandonment of pastures and reclaimed land occurred in the late 20th century. According to the data over the last 30 years, abandoned meadows are resistant to overgrowth with trees and shrubs. The spatial configurations of the floodplain landscapes have also been quite stable. The main spatial changes are confined to the near-channel floodplain, with the formation of new near-channel shallows. The floodplain landscapes of the Ob River demonstrate substantial spatial and temporal stabilities, and long-standing agricultural development.

Root systems reserve under humid conditions of floodplain meadows of the Ob River in the subzone of the southern taiga

The results of the study of the underground phytomass of the floodplain meadow communities in the Middle Ob obtained from three permanent sample plots in the area of the Kaibasovo research station of Tomsk University (Kri-vosheinsky district of the Tomsk region) are presented. The functioning and productivity of grassland ecosystems should be carefully studied, especially in the light of ongoing climate change, as they are actively involved in the carbon cycle. However, the belowground phytomass is given much less attention in the literature than the aboveground part, despite the fact that they are equally important for the study of the cycle. The study of vegetation cover in order to analyze the biological cycle of flood-plain ecosystems, the production and destruction of plant matter in this area was practically not carried out. The goal was to assess the structure and stock of root phytomass in the meadows of the Ob floodplain. In the course of the work, the hydro-climatic conditions of the growing season of the current and previous years were characterized in order to assess their impact on root development. The reserves of underground organs in the 0-20 cm soil layer were determined, the limits of fluctuations of the total reserves of roots in the 0-20 cm layer between the sampling periods in June and August were established.
 Key words. Belowground biomass, flood, floodplain meadows, productivity, roots, Western Siberia.

Неизвестный объект археологического наследия в обской пойме на территории Шелаболихинского района Алтайского края

The article is devoted to the analysis of a satellite image of an unknown object of archaeological heritage in the Ob floodplain, located in the Shelabolikhinsky Region of the Altai Territory. The purpose of the publication is to interpret the purpose of this archaeological site within the framework of its belonging to the settlements that have not yet been identified on the territory of this administrative entity. The characteristic of the location of this object meets all the basic natural territorial requirements necessary and sufficient for the construction of the settlements.

Change of water properties during the process of floodplain vegetation destruction

In laboratory conditions, the destruction of plant residues of floodplain plants in the aquatic environment was investigated. The subjects of the study were three species of plants that dominate the Ob floodplain: Inula salicina, Calamagrostis purpurea and Carex atherodes.Much attention was paid to dissolved organic matter (DOC), which plays a significant role in the aqueous environment. As a result of the work, species-specificity was revealed in the enleaching processes of macro and micro elements and organic matter from plants.It has been established that the process of destruction is primarily subject to representatives of the wild grasses.In the tested waters, in the structure of the DOC components, in the first fifty hours of the experiment, there was an increase in dissolved organic carbon, aroma substances and condensed carbon fragments, then the corresponding indicators were reduced, probably due to the mineralization of organic substances. Key words: destruction, flood, water properties, dissolved organic matter

The influence of seasonal changes on the formation of colloids and thin films of iron(III) hydroxide in Ob floodplain lakes

The research was conducted in the middle Ob floodplain. Several parameters (dissolved CO2, pH, conductivity, temperature, humin substances, Fe) were measured in six floodplain lakes in summer and autumn periods 2018. Temperature, conductivity and dissolved CO2 demonstrated the significant difference between these two samples.

Estimation of the ecological status of the Middle Ob floodplain water bodies

A comparative analysis of 4 lakes of the Ob riverbed floodplain was carried out. These lakes differ in the area, depth, overgrowing by higher aquatic vegetation and the flood effects. The assessment of the state of these water bodies was carried out on the basis of the ecological and faunistic analysis of zooplankton, studies of the water chemical composition, including general analyzes and determination of the chemical elements. All studied lakes belong to β-mesosaprobic reservoirs; but they differ in species composition, dominant complex, zooplankton biomass, and they have different stages of succession. The statistically significant associations of zooplankton biomass with concentrations of dissolved CO2 were revealed. The researches demonstrated that the surveyed lakes can be used as model ones in monitoring studies to identify the interannual, cyclic and successional processes.

Association Carici juncellae-Salicetum rosmarinifoliae (Alnetea glutinosae) on the south taiga section of the Ob River floodplain

The Carici juncellae–Salicetum rosmarinifoliae Korolyuk et Taran in Taran 1993 association (Salicion cinereae, Salicetalia auritae, Alnetea glutinosae) includes the communities of the shrub (Salix rosmarinifolia, S. cinerea)-birch (Betula pubescens) tussock (Carex juncella, C. cespitosa) mires spread on the big West Siberian river floodplains within the taiga zone. On the Ob River, the association is represented by the C.j.–S.r. spiraeetosum salicifoliae Taran 1993 subassociation. Its range covers the Ob floodplain 830-kilometer distance crossing the subtaiga, south taiga and middle taiga subzones of Western Siberia. In the south taiga subzone (surroundings of the former village Kaibasovo, Krivosheinskiy district of Tomsk Region, 57º14'44"N, 84º11'05"E), the C.j.–S.r. spiraeetosum salicifoliae subassociation is studied for the first time. Near the Kaibasovo, the subassociation is represented by two facies: shrubby (Spiraea salicifolia, Salix rosmarinifolia, Salix cinerea) and birch (betulosum pubescentis). The communities of these facies found some floristic differences, which made it possible to attribute them to different variants: var. Cicuta virosa and var. Kadenia dubia. Carex juncella, C. cespitosa and Comarum palustre dominate in the field layer of the tussock mires. In the C.j.–S.r. spiraeetosum salicifoliae subassociation communities near the Kaibasovo, the average total projective cover (TPC) of the tree layer is 7%, shrubs – 34%, grasses – 48%, tussocks – 20%, ground mosses – 14%. Average tussock height is 59 cm. Average species saturation of the communities is 27 species of vascular plants and 18 species of mosses per 100 m2, the volume of the local coenoflora is 39 species of vascular plants and 28 species of mosses. Six moss species (Brachytheciastrum velutinum, Bryoerythrophyllum recurvirostrum, Bryum moravicum, Fissidens bryoides, Plagiomnium cuspidatum, Pylaisia selwynii) were found in the Ob communities of the C.j.–S.r. spiraeetosum salicifoliae for the first time. Due to this, the total volume of the moss flora of the subassociation Ob stands increased to 74 species. The analysis of the variability of the main coenotic and floristic parameters of the C.j.–S.r. spiraeetosum salicifoliae subassociation in the geographical space of the Ob floodplain (from the subtaiga subzone to the middle taiga one) is carried out. The main regularities of these shifts are revealed. The volume of the subassociation local vascular coenoflora (52-53 species) and average species saturation of the communities by vascular plants (20-21 species per 100 m2) are stable on the most of the Ob floodplain sections. At the same time, changes are observed downstream of the Ob River, which can be interpreted as an intracoenotic response of the subassociation communities to smooth changes in the ecological regime of the floodplain when moving in geographical space from south to north. Thus, from the south to the north, many average parameters increase in the subassociation communities, namely: the height of trees, TPCs of tree layer, tussocks and ground mosses, the species saturation with mosses (from 4 to 18 species per 100 m2). The species richness of local moss floras also increases from 11 to 54 species. On the contrary, the average TPCs of shrub and field layers from south to north decrease. A number of deviations from general trends were found in the Kaibasovo birch-shrub tussock mires, namely: high species saturation with vascular plants (27 species per 100 m2), low reach of vascular coenoflora (39 species). The first can be explained by the proximity of the studied mires to the Ob riverbed, the second – by the crowding of the relevés in a relatively small area of the floodplain.

Contribution of floodplain lakes to the global carbon cycle

Inland waters are an important source of carbon. We measured concentration of carbon dioxide (CO2) and oxygen (O2), and some ancillary parameters in lakes of the Ob floodplain during several seasons. We received good correlations between carbon dioxide and oxygen concentrations, and studied dependence of CO2 concentrations on the time of day and the season.

Preliminary data to assess the impact of beaver dams on fish migration and the formation of fish resources in the Middle Ob River flood plain (Tomsk Region)

Field research enabled the identification of habitat features and the density of beavers’ habitats on a section of the Ob floodplain with an area of about 30 square kilometers. It was established that most beaver families live in lodges and regulate the water level at the sources of floodplain lakes by building dams. The research established that during the under-ice period in these lakes, the oxygen content decreases to below the critical level for the remaining lake-river fish, and dams are an obstacle to their migration to parts of the river system with a favorable oxygen regimen. An experiment was conducted with the descent of water through a dam built by beavers in the source of two floodplain lakes; the number and biomass of migrating fish were counted. On the basis of the obtained data on the species composition, size and weight of the fish, it is proposed that the damage to fish resources caused by the beaver dams in the Ob River floodplain may significantly exceed the commercial value of beavers.

The role of Eurasian beaver (Castor fiber) in the storage, emission and deposition of carbon in lakes and rivers of the River Ob flood plain, western Siberia

Several studies have reported significant emission of greenhouse gasses (GHG) from beaver dams, suggesting that ponds created by beavers are a net source of CO2 and CH4. However, most evidence come from studies conducted in North America (on Castor canadensis) without a parallel comparison with the Eurasian beaver's (Castor fiber) impacts and a critical consideration of the importance of the carbon deposition in dam sediments. The most abundant population of the Eurasian beaver lives in Russia, notably within the River Ob watershed in Western Siberia which is the second largest floodplain on Earth. Consequently, we assessed the holistic impact of Eurasian beavers on the multiple carbon pools in water and on other related biogeochemical parameters of the Ob's floodplain streams. We compared dammed and flowing streams in a floodplain of the middle course of the river. We found that beavers in western Siberia increase the stream emission of methane by about 15 times by building their dams. This is similar to what has been documented in North America. A new finding from the present study is that Siberian beavers facilitate 1) nutrient recycling by speeding up the nutrient release from particulate organic matter; and 2) carbon sequestration by increasing the amount of dissolved organic carbon. This carbon becomes in part recalcitrant when buried in sediments and is, therefore, removed from the short-term carbon cycle. These new results should be taken into consideration in river management and provide a further reason for the conservation and management of Eurasian Beavers.

The role of vertical structure in maintaining the stable functioning of meadow phytocenoses of the Middle Ob floodplain

The paper analyses the vertical structure of floodplain meadow communities of the Middle Ob and studies its association with yearly variations of weather conditions, soil regimes, and changes in the species composition of the grass stand. The vertical structure reflects the average annual conditions of floodplain ecotopes and is an adaptive mechanism for the stability of meadow phytocenoses during environmental dynamics.

Bio-diversity and population structure of rove beetles (Coleoptera, Staphylinidae) in the flood plain habitats of the Ob and Irtysh basin

The study of Staphylinidae fauna in the Ob river flood plain was conducted from May to September 2010, and in the Irtysh flood plain from May to August, in 2013–2014. Pitfall traps together with hand collecting and soil sample sorting were used. The maximal bio-diversity (32 species, with Philonthus decorus Grav. dominating) and density of rove beetles were registered in the small-leaved forests of the Ob flood plain. In the Irtysh river flood plain rove beetles demonstrated maximal bio-diversity (16 species) in willow-shrub, Gymnusa brevicollis Grav., Philonthus albipes Grav. and Philonthus agilis Grav. dominating. Most Staphylinidae prefer wet and warm places, like an inner part of fluvial sediments or upper level of forest litter. In the forests’ ecosystems the peak of activity takes place between the beginning of June and mid-July, but it shifts to the end of summer in the wetlands of the Ob and Irtysh flood plain.

The ecological peculiarities of the testate amoebae population in the Middle Ob flood plain

The biodiversity and distribution of testate amoebae in the Middle Ob flood plain soils have been studied. The biodiversity of Testacea in the soils consists of 83 species and varieties from 12 families. The population of Testacea in flood plain habitats is rich in water forms, especially in the flood plain part of the catena, because of annual floods. The study showed that the density of Testacea in the forest plots is approximately 10 times higher than in the meadow ones. The species diversity of Testacea in the meadows of the flood plain includes 40 species and varieties. It was found that there is an enrichment of the fauna of Testacea in the flood plain meadows with water forms and a decrease in the population of Testacea in the soil according to the depth. The decrease in the diversity and number down the soil profile is related to the decrease in the amount of the oxygen available and general induration of soil. On the whole, the population composition of Testacea in the soils of the pine forest consists of typical representatives of humus substrates with low values of pH, small stock of humus and mineral nutrition. The soils of mature pine forests are rich in Testacea; they have a similar complex of morphological types, mainly because of the moss cover and forest litter thickness.

The concentration of Mn, Cu, Zn, Co, B, Sr, Cd and Pb in alluvial soils of the Ob River (forest-steppe, southern taiga and central taiga)

Three areas of the Ob River floodplain (forest-steppe, southern taiga and central taiga) were investigated. The total amount of Mn, Cu, Zn, Co, B, Sr, Cd and Pb was identified. The same elements were identified in ammonium acetate buffer extract, 1N HCl extraction and Tamm’s and Grimm’s soil extracts. The basic amount of trace elements in the soils is in the potentially unstable form, in Tamm’s and 1N HCl extracts (up to 74% of the total amount). The geochemical spectra of the investigated elements’ concentration in the soils and meadow vegetation are given. The Ob floodplain is not polluted as it has not been affected by industry, and that is why natural mechanisms of these soils can be easily detected. The content reduction regularity of most of the trace elements and their unstable forms in the soils from the south to the north of the Ob floodplain is observed. The same regularity concerns plants in which Co, Mo, B, Sr and Cd contraction and Mn, Zn and Cu increase are detected.

Simulation of the Floodplain Territories Inundation for the Major Rivers’ Parts with Complicated Morphometry of the Bed and Floodplain

A non-stationary planned (2DH) model of flow has been considered in order to forecast inundation of floodplain territories on the prolonged ranges of major rivers as a result of spring-summer high-water periods and rain floods. Digital implementation of the mathematical 2DH-model has been proposed. It was aimed at calculation of actual flows for the cases with complicated morphometry of bed and floodplain. A computer model of flow in accordance with the CADAM experimental conditions has been made and test computations have been carried out. The developed digital planned model has been applied for computation of inundation of the Ob floodplain in the vicinity of Barnaul in the conditions of variable water content.