Irrigation expansion and dynamics of desertification in the Circum-Aral region of Central Asia

The aim of this paper is to examine the causes and dynamics of desertification in one of the world's worst disaster areas, the Aral Sea region. During the 1960s, a large-scale irrigation campaign aimed at achieving independence in cotton production was launched in Soviet Central Asia. From 1960, ever-increasing water withdrawal from the two inflowing rivers—the Amudarya and Syrdarya—has resulted in the dramatic decline of the level, area and volume of the sea. Desiccation was accompanied by the development and further acceleration of various desertification processes. The study reveals that, for different reasons, the predominant direction and trends of desertification have been changing during each of the four identified periods from 1961 to 1995. The main desertification processes recorded in the Circum-Aral region (‘Priaraliye’ in Russian) were a decline in the groundwater level, increased mineralization and chemical pollution of watercourses, soil salinization, the spread of xerophytic and halophytic vegetation, and deflation and aeolian accumulation, with the development of salt storms. Recent improvements in the situation are also discussed, along with their causes. Zonation of Priaraliye is carried out and an outlook for the future is given.     

The interacting subsystems theory of active galactic nuclei – I. The broad-absorption-line QSO theory

The theory of broad-absorption-line (BAL) QSOs is worked out on the basis of the radiation hydrodynamics equation solution for the two-phase media of active galactic nuclei. We suppose that the BAL QSO physics depends on some 'hidden' AGN parameters, such as the mass and size of the compact stellar system. We therefore approach this problem in the more general framework of the 'interacting subsystems theory', which includes these parameters. We compare the results of the numerical model calculations with the observed spectra and show that the BAL QSOs (and the radio-quiet quasars as well) contain massive compact stellar kernels in their central regions. We show that the line-locking effect is determined by the radiation pressure, and is also favoured by the drag force of the hot gas acting on the line-absorbing clouds.
We derive some general conclusions about the physics of AGN. In particular, we show that the radio-quiet versus radio-loud dichotomy can be explained by using two types of hot gas outstreams in quasars.     

Geochemical features of rare-earth elements in surface and subsurface waters in the field of the Albynskoe Gold-Bearing Placer,Amur oblast

The distribution and fractionation of rare-earth elements (REE) are studied in the surface and subsurface waters and rocks of the Albynskoe Gold-Bearing Placer. The obtained data show the rocks of the placer to be enriched with rare-earth elements and to feature the predominance of light lanthanides over heavy ones. Groundwater show an equality between the groups of light and heavy lanthanides, while in the surface waters the concentration of light REE is much higher than that of heavy ones, thus reflecting the composition of the drained ore rocks. The leaching of rare-earth elements from rocks by atmospheric water is intensified by agents produced by microorganisms in their vital activity.     

Distribution of alkalinity and dissolved calcium in the Sea of Okhotsk

During the summer seasons of 2002 and 2004, the total alkalinity (TA) and dissolved calcium (Ca) were studied at 41 stations in different areas of the Sea of Okhotsk: the Kuril depression, Deryugin Basin, the slopes of the Kamchatka Peninsula and Sakhalin Island, and in Sakhalin Bay. It was shown that the distributions of the TA and Ca in the water mass of deep sea areas are determined by the processes of CaCO₃ formation and dissolution according to the relation Δ Ca = 0.5 Δ TA (1). The variations of the TA and Ca values observed in the upper 10-m layer and in the near-bottom layers of local depressions in the Deryugin Basin do not satisfy relationship (1). Probable reasons for this discrepancy are considered: organic matter mineralization, mixing of water masses with different preform TA and Ca values, sea ice melting, runoff from land, and sea bottom effects. It is shown that the enrichment in the alkalinity and calcium is caused by the Amur River runoff in the desalinated sea surface layer and by the high geochemical activity in the Deryugin Basin in the near-bottom 200-m layer of local depressions.