The project was devoted to solving the key problem of the arctic and subarctic regions’ environment: how far the climate warming in these vast areas of Russia is going to effect the functioning of natural ecosystems and basic biogeochemical cycles, human activity and economics.
The project had two aims: (i) to provide new and crucial information to predict the trend and degree of the changes in the fluxes and mechanisms of the biogeochemical transfer of matter in the high latitude areas driven by climate warming; (ii) to create new hydrochemical models of the transfer of carbon and conjugate elements that might describe the fluxes of the transfer of matter in the permafrost conditions based on the observations in-situ.
The project objectives’ originality and scientific novelty were the following:
1) Addressing to a specific hydrological regime in the permafrost zones from peat deposits and forests to the tundra vegetation.
2) The quantitative modelling of the fluxes and concentration as well as occurrence form of both carbon and conjugate elements with the focus on the analysis of organic-mineral colloids.
3) The quantitative assessment of the role of temperature, solar radiation and chemical composition of surface waters in the greenhouse gas emission from thermokarst lakes using experiments in-situ in the controlled macrocosms (of the ecosystem level).
The following tasks corresponding the set objectives were solved:
1) What are the factors controlling the permafrost hydrological regime at the local (small watershed) and global (2,500-kilometre latitudinal transect) scale?
2) How do the active layer thickness and the degree of permafrost covering influence the dynamics of organic carbon and conjugate elements within the continuum plants – soil - river?
3) How can the ongoing global warming and permafrost thawing in high latitudes change the hydrochemical/biogeochemical fluxes of carbon and conjugate elements from soils to rivers and further to the ocean and CO2 and CH4 emission from lake surface to the atmosphere?
4) What are the basic physical, chemical and biological factors that control the greenhouse gas emission from thermokarst lakes to the atmosphere?
These tasks were solved by means of a coordinated interdisciplinary study of the evolution of natural ecosystems in the climate and permafrost gradients of Western Siberia. There were here basic research sites corresponding to various types of permafrost (continuous, discontinuous and sporadic). The research in the transfer of carbon and conjugate elements was done in a unique mega-profile 2,500 km long located along a latitudinal transect of three areas with the similar lithology and vegetation but with different mean annual temperatures, thickness and degree of permafrost covering.
The project implementation formed the image of Western Siberia as a unique natural mega-installation regulating the Earth’s climate to a considerable degree, being easily accessible for researchers and attracting the world scientific community, which may make the foundation for starting large net projects and research consortiums.
To reach these academic and scientific goals a world-class environmental laboratory was established at TSU, which became the nucleus of a forming interdisciplinary research cluster in the field of geoscience and bioscience – the Centre for Research into Biota, Climate and Landscape (BioClimLand), one of the five priority development trends included into the university road map.
The bulk of the project works done dealt with studying the hydrochemical parameters of the most dynamic landscape components – rivers and lakes. The factorial analysis of the hydrological regime of rivers showed that in the sporadic permafrost zone no one of run-off forming factors separately (precipitation, thermal regime, surface moisture, landscape conditions) determines the amount of river flow. This value correlates with a combination of factors only, taking into account their genetic connection with each other in the form of water-balance models.
Studying the hydrochemical parameters of rivers and the processes taking place in their watersheds allowed revealing the main environmental factors controlling the transportation of dissolved components in the rivers in Western Siberia. In 2,000-kilometer latitudinal mega-profile the research of more than a hundred small and large rivers with various watershed areas was done for the period of three years. The samples were taken in winter, spring, summer and autumn. The research resulted in revealing a latitudinal trend – the decrease in the concentration of DOC, DIC, SO42– and basic ions (Ca2+, Mg2+, Na+, K+) northwards. The trend of inorganic components is clearly seen in the winter hydrological season and is less noticeable in spring. The trend of the decrease in the concentration of DOC along the latitude is not observed in winter and is less noticeable during spring flooding compared to summer when underground waters penetrate to surface ones with surface flow being insufficient. The trends are significant for river basins of all sizes. The flows of dissolved components depend insignificantly on the size of a river basin and are a function of a watershed of a mean width. The DOC flow is stable approximately 3 t/km²/year up to 61°N, halves in the discontinuous permafrost zone (62–66°N) and increases to 3 t/km²/year in the continuous permafrost zone (67°N). DIC, Mg, K and Ca have the same trend. Also at the model site located in the river basin of the Middle Ob the influence of the flooded area on the behaviour of DOC and connected metals during flooding was studied.
Large areas in flat interfluve basins of West Siberian Plain are taken by lake-wetland systems. Being interactive participants of the global climate change they are also the indicators of the environmental changes. In connection with this a model of thermokarst lakes’ dynamics was developed. It is shown that for the time being permafrost degradation is observed in the north of Western Siberia, and the number and area of thermoakrst lakes grow. The procedure of determining the amount of methane accumulation in the lakes located in a particular permafrost area was developed and described based on the results of mathematical modelling of the spatial structure of thermokarst lake fields.
The seasonal variations in biogeochemical processes in thermokarst lakes in the northern taiga of Western Siberia were assessed. The chemical composition of more than 130 thermokarst lakes in various seasons was described. The comparative research in thermokarst lakes in Western Siberia in various seasons was done for the first time; it allowed revealing the contribution of winter freezing into the dynamics of dissolved and colloid forms of elements in water as well as their geochemical connection with forming bottom sediments. It was stated that larger lakes (with an area of 1,000 m2) do not show a statistically significant control over the concentration of DOC, macro- and microelements by the lake size during three main hydrological seasons with open water surface. Yearly, most dissolved elements including DOC increase their concentrations from 30 to 500%, with a statistically significant (p <0.05) trend from spring to winter. The concentrations of most microelements (TEs) increase in the row spring > summer > autumn > winter.
For the first time the mechanisms and peculiarities of the transformation of the chemical composition of lakes in winter were studied. It was shown that ice-forming in the thermokarst lakes in October includes several stages: the surface layer freezes, then cracks are formed in the ice through which water comes out of deeper layers and spreads over ice surface. Later it freezes and forms ice layers rich in organic matter. As a result, DOC and concentrations of metals (Mn, Fe, Ni, Cu, Zn, As, Ba and Pb) were the highest near the surface of an ice column (from 0 to 20 cm) and reduced with a factor of 2 towards its lower part. The main biogeochemical significance of the discovered effect of freezing on solutions’ concentrating in the water of the thermokarst lakes is in its fostering colloid coagulation and taking away dissolved organic matter, which binds non-soluble metals in water thickness.
Soils and soil cover are the base of any catchment area forming hydrochemical features of water bodies and greenhouse gases’ emission to the atmosphere. This control is realized through the transformation of precipitation composition during their interaction with organic matter and mineral matrix in the soils. All this caused studying soils and soil covers in the key sites along the latitudinal mega-profile; the research in soil solutions, the most mobile soil phase in the landscape aspect, started. The field and laboratory experiments resulted in determining the morphological, chemical and physical characteristics of soils, based on which the classification of soils was done using «World Correlation Database of Soil Resources» and «Classifications and Diagnostics of Soils in Russia» (2004).
Studying catenas with the leading role of podzols and podzolized brown soils showed that in the climate conditions of the sub-Atlantic stage of the Holocene the automorphous sandy soils of discontinuous permafrost were subjected to phytogenous turbations to the depths of 60 – 70 cm, which influenced the dynamics of the chemical elements from paragenetic association in alpha-humus horizons’ penetrating the zone of over-permafrost spring leakage water. It should be noted that the possibility of such deep phytogenous turbations was not mentiond in literature, and the observed turbation polymorphones in north-taiga podzols and podzolized brown soils were classified as cryogenic formations that had emerged in the early Holocene periods. Having counted the area of modern blowdown soil complexes we showed that for 9,000 years about 30 % of soil cover area could have passed the blowdown stage. Thus, even under such severe conditions they still have a significant morphogenetic influence on the podzol profile structure not only through chemical and physical-chemical processes but also through mechanic mixing due to blowdown. The basic factors that restrict blowdown morphogenesis in the northern taiga are fires and soil hydromorphism.
The wetlands occupy a considerable part of the area under study, which is the reason why their chemical and microbiological parameters were studied. It was found that the chemical composition of the peat soils under study depends on several factors: the combination of peat formers; the biogenic, radial and lateral migration of the chemical elements on forming peats in the result of bog water moving in peat deposits. Measuring the concentrations of macro- and microelements in the drill samples collected along the latitudinal gradient in West Siberian Plain (2,000 km) while studying basic biogeochemical parameters of natural environments showed a relatively equal distribution of most microelements along the permafrost gradient from the unfrozen peat in the south to the northern borderline of discontinuous permafrost. The upper part of the peat column consisting mainly of green Sphagnum was rich in bivalent metals unlike the peat bulk. The decrease in the Mn and Cu concentration and increase in Na, K and Rb concentration accompanied by growing moss production were found. The intensity of moss mineralization is connected with accumulation of slow-moving Fe, Al, Ti, bivalent metals and non-metals.
The research in soil solutions that are the initial components of the geochemical flows determining their hydrogeochemical parameters was started. It was shown that the permafrost emergence within the soil profile in the latitudinal transect causes changes in the hydrochemical parameters of the soil solutions. This effect appears not only in mineral soils but also in peats, which has not been known before.
Microscale studies at the level of elementary soil habitats and microcatenas made it possible to find out the rapidly going efflux of fine organic matter and its sorption from Bfe horizons in podzols. These processes are responsive to the ones in the ground cover and higher biogeohorizons. We found that the mechanism of fine-divided carbon efflux occurs in wetland soils as well.
Based on the data on drilling permafrost peat lands and studying mineral soils we showed that the inherent factor that determines the landscapes of the cryolithic zone to a great extent is pyrogenesis that used to cause both waterlogging due to the disconnection of biological cycles of elements and the increase in the nutrients’ eluviation in the upland conditions of the modern forests in the permafrost zone. The analysis of satellite images showed that on the borderline between the tundra and forest-tundra forest colonization of an area may happen after forest fires destroying the moss-lichen cover and enhancing the growth of such a pyrophilic species as the larch.
We studied the stable isotopes of a number of elements, which revealed that permafrost areas’ peculiarity is a low involvement of the mineral horizons and ground waters into forming isotopic relations, which facilitates the role of the biogenic factor whose role may lessen with climate warming as permafrost mineral horizons of the soil thickness become involved into the active zone.
An important ingredient of the formation of the hydrochemical flow from autonomous wetlands is the precipitation composition. Studying them in winter period revealed the man-driven sources of atmospheric precipitation pollution. The highest concentration of non-soluble particles was found near Tomsk and in the area between Surgut and the village of Gubkinsky. The samples contained mainly mineral particles apart from which there were the biogenic particles and the particles that had formed in the processes of various fuels’ burning out (ash and black carbon).
The results of studying carbon balance and production-destruction processes of the ecosystems of the cryolithic zone in Western Siberia in the model site “Khanymey” showed that the stock of living phytomass are formed by various groups of plants in various relief types: in depressions, hollows – by sedges and cotton grass; in the raised relief elements, in mounds – by shrubs and dwarf shrubs, and the stock of the mortmass is 70 % of the total stock of plant matter. The structure of the production BNP/ANP(mosses)/ANP(dwarf shrubs and herbs) correlates as 7/3/2 in mounds and 5/10/1 – in hollows. The below-ground net production is 60 – 70 % of the total production.
We studied the interrelations between the metabolic activity of microbial communities and peat characteristics. The botanical composition and decomposition rate influence rather the nitrogen concentration than carbon concentration. The higher the nitrogen concentration in the active layer is, the more active the microbial communities are.
The model microorganisms’ adsorption of chemical elements and compounds based on experimental studies was described. The results display the universal for various microorganisms adsorption parameters that control the interaction between metals and bacterial surface with high metal concentrations in the water solution and biomass.
The research in permafrost landscapes in the north of Western Siberia made it possible to study the peculiarities of their changes and confirmed the prospects of the suggested approaches to solving the tasks of monitoring the response of the geosystems of water-logged and autonomous landscapes of the cryolithic zone to the global climate changes. The combined studies of the climate change indicators and regulators done will help to find out how the climate long-term dynamics is going to effect the environment in Western Siberia.