The principles in studying the natural and technogenic dynamics of Siberia's landscapes

Conceptual-methodological approaches in understanding the dynamics and tendencies of directional changes in landscapes include a universally recognized top priority approach, i.e. the functional-integration principle of temporal observations of self-regulation processes occurring in the case of an inter-component exchange of substances. Our main concern is with the migration-accumulation mechanisms of spatial differentiation of chemical elements. Experience is examined, which has been gained from experimental studies of the technogenicgeochemical transformation of landscapes under the influence of pollutants emission from industrial facilities of two types. We summarize the research results obtained according to the following pattern: monitoring, indication of disturbances, forecasting, and regulation of technogenic loads on the natural environment. On the whole, the case in point is that modern complex geography is switching over to a level of experimental investigations of the territory.     

Radiophysical Monitoring of the Lake Baikal Ice Cover

Presented are the results of the winter 2014 radiophysical expedition, within the framework of which the Baikal ice cover was investigated by electromagnetic methods. The primary objectives the expedition were to detect irregularities in the ice cover, such as cracks and thawing steamed holes in the ice, and to determine the ice thickness and structure in the area of the thawing holes by the GPR sounding method. We used in the experiments the OKO-2 ground-penetrating radar (GPR) of the decimeter band and the nanosecond radar with the wavelength of 3 cm. The measurements were made carried out from the Khivus hovercraft and from the UAZ automobile. The ice thickness of Lake Baikal was determined by non-contact electromagnetic measurement methods. Radargrams of reflected signals from the ice cover are presented. Radar patterns of reflected signals from artificial irregularities of the ice cover were obtained by the short-pulse radar method. The concept of radiophysical monitoring is suggested, which provides a means of determining the ice cover parameters of a water body with high spatial resolution. We present an integral approach to investigating the conditions of the ice cover in order to integrate different physicochemical methods for diagnosing the objects studied. A further development of the concept of integrated ice cover research, and the creation of the monitoring network involves solving a number of scientific and engineering tasks that include developing physical models and information and measurement systems as well as the rationale for an integrated monitoring network.     

The use of some parameters of carbon cycle in assessing the functional organization levels of landscapes (using the Lake Baikal watershed basin as an example)

Presented is the technique for calculating the indicators characterizing the degree of organization of landscape, based on determining the parameters of carbon cycle which are amenable to accurate numerical accounting: the amount of C that oxidizes within the soil-ground layer, and the amount of organic C that is carried with the runoff. Published data on chemical composition of surface waters were used as input information for calculations. On the basis of the indicators obtained, the level of functional organization of landscape was assessed. It was assumed for the sake of convenience that the significance of all indicators was identical. For further assessments of the levels, it is suggested that the significance of the indicators determined by the range of their values be taken into account.     

32Si dating of sediments from Lake Baikal

We applied the ³²Si dating technique to a sediment core from Lake Baikal to obtain the sediment chronology for the last millennium. The core was recovered about 4 km offshore from the north slope of the South Basin in 1,366 m water depth. The sediment material consisted of continuously accumulated diatom-rich geogenic-terrigenous mud, intercalated with a number of dark olive-grey turbidite layers. The sediment layers containing the turbidites were excluded from ³²Si sampling to obtain the chronology that is representative of the continuous sedimentation. The initial ³²Si activity of 31.3 dpm kg^?1 SiO₂, measured in sediment trap samples, confirms the trend of ³²Si specific activities of biogenic silica found in other Northern Hemisphere lakes. The four sediment core samples from depth 0–48 cm have ³²Si specific activities between 23.5 and 0.5 dpm kg^?1 SiO₂, with corresponding ages between 60 and 860 years and constant sedimentation rate of 0.036 ± 0.004 cm year^?1 over the most recent 800 years. ³²Si allowed us for the first time to date the uppermost turbidites in the South Basin of Lake Baikal, to 1030, 1310 and 1670 ad. Given these dates, the last long-distance turbidity current triggered by slope instabilities had occurred 330 years before 2000 ad, and the intervals between the 1310 and 1670 ad event and between the 1030 and 1310 ad event were 360 and 280 years, respectively. The ³²Si ages allow unprecedented time resolution for reconstruction of the former environmental and climatic conditions during the past millennium.     

Siliceous microfossil distribution in the surficial sediments of Lake Baikal

Examination of surficial sediments at 16 stations shows minor, but consistent differences in the numbers and kinds of siliceous microfossils deposited in different regions of Lake Baikal. There is a general north-south decreasing trend in total microfossil abundance on a weight basis. Endemic plankton diatom species are the most abundant component of assemblages at all stations. Chrysophyte cysts are present at all stations, but most forms are more abundant at northern stations. Non-endemic plankton diatom species are most abundant at southern stations. Small numbers of benthic diatoms and sponge spicules are found in all samples. Although low numbers are present in offshore sediments, the benthic diatom flora is very diverse. Principal components analysis confirms primary north-south abundance trends and suggests further differentiation by station location and depth.     

The ecologo-geomorphological consequences of conservation of agricultural lands within the Lake Baikal watershed basin

The results derived from analyzing the long-term dynamics of the runoff of sediment loads of the main rivers in the agricultural areas of the Lake Baikal watershed basin are discussed. The analysis revealed a descending trend of the erosion processes caused by an abrupt change of agricultural activity in the region, i.e. a reduction in the area of arable and pasture lands in the late 20th century. It is shown that a decrease in basin erosion intensity promotes stabilization of desertification processes and, in general, an improvement of the ecological situation in the Baikal region.     

The entry of sulfates and nitrogen into Lake Baikal with the waters of its influent rivers

The dynamics of the entry of sulfates and nitrate nitrogen into Lake Baikal together with its influent waters is outlined. Changes in the discharge of chemical components by large water streams are largely determined by the entry of ingredients as part of effluents. It is shown that the current increase in the flow of pollutants from the atmosphere has a dramatic effect on chemical composition of water in small rivers of Southern Baikal with low mineralization.     

Baseline levels of chemical elements in the water of Lake Baikal

Evidence for levels of five major elements (Na, Mg, Si, Ca, and K) and 53 trace elements (Li, Be, B,..., Pb, Th, and U) in the water mass of Lake Baikal is provided. The baseline levels of the elements were obtained from analyzing and summarizing the most reliable data published during the last 15 years, including these authors’ data. Most of the article focuses on an overview of the methodologies as used in the investigations involved (sampling techniques, and sample storage, processing and analysis methods). The summary table provides the most reliable concentration ranges for 58 elements which are recommended by these authors as background (baseline) levels.     

Landscape-Hydrological Assessment of the Lake Baikal Coast for Recreational Development Purposes

This paper considers the theoretical and methodological aspects of landscape-hydrological analysis in substantiating the possible development of recreational activities within the boundaries of the central ecological zone of the Baikal natural territory (BNT CEZ) in Irkutsk oblast. The hydrological characteristics of the landscapes in terms of their sensitivity and resistance to natural changes and external influences are given. We carried out a landscape-hydrological zoning for the BNT CEZ territory within the boundaries of Irkutsk oblast having regard to the conditions of runoff formation, the characteristic features of its regulation in various landscapes, and to the possibility of preserving the natural water regime and the waterecological state in utilizing the territory. It is determined that the main factors for the landscape differentiation in assessing the advisability of recreational development without damage to the Lake Baikal ecosystem and to the natural waters of BNT CEZ as a whole are the hydrological properties of landscapes and resistance of natural complexes to impacts. It is found that the level of realization of the main hydrological functions of landscapes, i. e. the runoff formation, runoff regulation and water protection functions, characterizes the involvement of the natural complex in the formation of quantitative and qualitative characteristics of the local runoff, in the replenishment processes of dynamical reserves of subsurface waters, the regulation of natural floods and freshets, the preservation of the water-ecological potential of the territory. As a result a landscape-hydrological framework zoning of the territory using the landscape planning tools, three zones have been identified: the zone of the preservation of the existing state, the zone of regulated use, and the zone of territorial development. The proposed zones have general recommendations for the preservation of the hydrological and water-ecological indicators of the natural complexes which imply abandoning any activity in areas of particularly high value and highly sensitive to impacts, and the possibility of developing recreational activities in sustainable areas, subject to environmental protection measures.     

Distribution of minor gas pollutants in the atmosphere over Lake Baikal

An analysis is made of the data obtained by means of the gas analyzer in comparison with meteorological conditions. The values of sulfur and nitrogen dioxide concentrations in the layer above water of Lake Baikal varied from 1 to 10 micrograms. The largest values of SO₂ concentration were observed in the area of the Baikalsk Pulp and Paper Mill (Southern Baikal) under the plume. The calculated and measured values of sulfur dioxide and nitrogen oxide concentrations were compared to provide a good qualitative agreement.     

Hydrological factors in landscape planning of the Lake Baikal Watershed Basin

We outline the essentials of landscape planning of a territory from the water factor at the stage of assessments and summarizations of a natural character. We explore the possibilities of assessing the water potential and the goals of ecologically oriented land use planning. We formulate a number of recommendations and suggest a target-oriented zoning of the lake’s watershed basin with respect to the water factor with a focus on maintenance of the quantity and quality of waters entering Lake Baikal.     

A synthesis of post-glacial diatom records from Lake Baikal

The biostratigraphy of fossil diatoms contributes important chronologic, paleolimnologic, and paleoclimatic information from Lake Baikal in southeastern Siberia. Diatoms are the dominant and best preserved microfossils in the sediments, and distinctive assemblages and species provide inter-core correlations throughout the basin at millennial to centennial scales, in both high and low sedimentation-rate environments. Distributions of unique species, once dated by radiocarbon, allow diatoms to be used as dating tools for the Holocene history of the lake. Diatom, pollen, and organic geochemical records from site 305, at the foot of the Selenga Delta, provide a history of paleolimnologic and paleoclimatic changes from the late glacial (15 ka) through the Holocene. Before 14 ka diatoms were very rare, probably because excessive turbidity from glacial meltwater entering the lake impeded productivity. Between 14 and 12 ka, lake productivity increased, perhaps as strong winds promoted deep mixing and nutrient regeneration. Pollen evidence suggests a cold shrub — steppe landscape dominated the central Baikal depression at this time. As summer insolation increased, conifers replaced steppe taxa, but diatom productivity declined between 11 and 9 ka perhaps as a result of increased summer turbidity resulting from violent storm runoff entering the lake via short, steep drainages. After 8 ka, drier, but more continental climates prevailed, and the modern diatom flora of Lake Baikal came to prominence. On Academician Ridge, a site of slow sedimentation rates, Holocene diatom assemblages at the top of 10-m cores reappear at deeper levels suggesting that such cores record at least two previous interglacial (or interstadial?) periods. Nevertheless, distinctive species that developed prior to the last glacial period indicate that the dynamics of nutrient cycling in Baikal and the responsible regional climatic environments were not entirely analogous to Holocene conditions. During glacial periods, the deep basin sediments of Lake Baikal are dominated by rapidly deposited clastics entering from large rivers with possibly glaciated headwaters. On the sublacustrine Academician Ridge (depth = 300 m), however, detailed analysis of the diatom biostratigraphy indicates that diastems (hiatuses of minor duration) and (or) highly variable rates of accumulation complicate paleolimnologic and paleoclimatic reconstructions from these records.     

Sedimentation history of the Selenga Delta, Lake Baikal: simulation and interpretation

The computer simulation of a Lake Baikal seismic profile located in the Selenga River Delta area resulted in a lake level record of the last 600 kyr. This curve demonstrates several low-magnitude episodes and both a dramatic 300 m fall and a more than 150 m increase of the lake level relative to present situation. The greatest change in paleo-lake depth at 300 ka corresponds in time with the major glaciation in the Eastern Siberia and is probably the response of the lake to this climatic phenomenon. The results of this study conform with existing hypotheses on the regional tectonic history and climatic events.     

Magnetic properties of recent sediments in Lake Baikal, Siberia

Mineral magnetic measurements of six ²¹⁰Pb-dated surface cores from different basins of Lake Baikal, Siberia, show temporal records controlled by a range of internal and external processes. With the exception of sediments on the Academician Ridge, there is clear evidence for widespread reductive diagenesis effects on the ferrimagnetic component coupled with neo-formation of paramagnetic iron minerals. Greigite formation, bacterial magnetosome accumulation and turbidite layers may affect the properties of some sediment levels. Concentrations of canted antiferromagnetic minerals (eg. haematite) appear to increase from the 19th century onwards. These minerals are less affected by dissolution processes and probably represent detrital minerals delivered by catchment fluvial processes. The magnetic evidence for recent atmospheric pollution by fossil-fuel combustion processes is weak in all the cores, and supports the findings from studies of spherical carbonaceous particles (SCPs) and heavy metals that pollution is largely restricted to the southern basin. Correlations between recent sediments based on magnetic data may be insecure over long distances or between basins.     

A 640 kyr geomagnetic and palaeoclimatic record from Lake Baikal sediments

Magnetic remanence vectors for 1737 samples from two ∼100 m cores of Lake Baikal sediments are reported along with complete magnetic susceptibility profiles obtained from a pass-through system. Chronological control is established by means of two independent correlations; first, by matching susceptibility variations to the oceanic oxygen isotope record and second, by matching the relative palaeointensity variations to the SINT-800 global reference curve. These both imply an average deposition rate of 15 cm kyr^–1 and a basal age of ∼640 ka. Spectral analysis reveals the presence of Milankovitch signals at ∼100 kyr (eccentricity), ∼41 kyr (obliquity) and ∼23 and ∼19 kyr (precession). Stable remanence vectors are almost all of normal polarity. The few exceptions comprise brief intervals of low and/or negative inclinations which probably represent geomagnetic excursions. However, these are far less numerous than the high sedimentation rate would lead one to expect. Furthermore, only four of them can be readily matched to the—still poorly understood—global pattern. These are the Laschamp, the Albuquerque, the Iceland Basin and perhaps the West Eifel excursions which occurred at ∼38 000, ∼146 000, at 180 000–190 000 and at 480 000–495 000 yr ago, respectively.     

Using the status of a world heritage site for the preservation of Lake Baikal

This paper is concerned with the implications of the status of World Natural Heritage Sites, the position of the Russian state on the issues related to observance of the provisions of the Convention Concerning the Protection of the World Cultural and Natural Heritage, and the authorities-civil society relationships on these problems. An analysis is made of the possibilities of effectively using the world heritage institute in Russia in the interests of preserving world values. A number of legal and organizational measures for their conservation are suggested.