Discovery of a young planetary-mass binary

We have identified a companion to the young planetary-mass brown dwarf Oph 162225-240515. This pair forms a resolved binary consisting of two objects with masses comparable to those of extrasolar giant planets. Several lines of evidence confirm the coevality and youth of the two objects, suggesting that they form a physical binary. Models yield masses of approximately 14 and approximately 7 times the mass of Jupiter for the primary and the secondary object, respectively, at an age of approximately 1 million years. A wide ( approximately 240-astronomical unit) binary in the ultra-low-mass regime poses a challenge to some popular models of brown dwarf formation.     

Synlithogenic Evolution of Floodplain Soils in Valleys of Small Rivers in the Trans-Ural Steppe

Eurasian Soil Science - The relationship between soil formation and sedimentation on the floodplain of the Utyaganka River (the Ural River basin) in the Arkaim Reserve (Chelyabinsk oblast, Southern...     

Radiocarbon ages of humic substances in chernozems

Data on radiocarbon ages of different fractions of humus (humic acids, fulvic acids, and humin) in the profiles of chernozems are analyzed. A chronoecological grouping of humus in modern and buried (fossil) soils is suggested. An increase in the radiocarbon age of humic substances down the soil profile has a stepwise character. It is shown that the ¹⁴C content in chernozems decreases down the soil profile more somewhat slower than the ¹²C content. The dependence of a decrease in the humus content of buried soils on the age of burying is traced for a time span of 800 ka.     

Assessment of the State of Soils and Vegetation in Areas of Landfills and Municipal Solid Waste Sites (a Review)

An overview of modern ideas on the ecological and geochemical state of soils and vegetation in the sites of landfills and municipal solid waste storage is presented. The technogenic impact on the environment and soil is determined by the (1) withdrawal of land for landfills, (2) production of filtration water with toxic components upon decomposition of solid wastes, and (3) biogas generation. The heavy metal pollution of surface soil horizons is characteristic for the sites of solid waste storage and their impact zones irrespectively of climatic conditions, ways of waste management, and stages of the life cycle. At the same time, heavy metals accumulate in ruderal herbaceous plants. Changes in the geochemical and microbiological characteristics of soils and disturbances in the plant cover are not restricted to the area of the designated sanitary protection zone. Buried landfills, where the decomposition of organic matter under anaerobic conditions results in the production of carbon dioxide and methane with their concentration in the soil and ground air also become dangerous for the environment. In the sites of landfills and municipal solid waste storage, weakly developed surface and chemically transformed soils, technosols and technogenic surface formations are being formed.     

Cesium-137 Root Uptake by Oat and Lettuce Test Crops from Radioactively Contaminated Chernozem under Model Experiment Conditions

The features of cesium-137 (¹³⁷Cs) root uptake by spring oat (Avena sativa L.) and lettuce (Lactuca sativa L.) plants have been studied in a model experiment with simulation of radionuclide fallout into undisturbed monoliths of arable chernozems from the Plavsk radioactive spot. An integrated approach using digital autoradiography and γ-spectrometry methods has revealed a uniform pattern of vertical and lateral ¹³⁷Cs distribution in the soil profile and low bioavailability of the radionuclide or root uptake by plants. Certain biological features of the test crops with respect to root uptake of ¹³⁷Cs have been demonstrated: limited translocation of the element into shoots via its relative accumulation in roots for oats and limitation of general root uptake of ¹³⁷Cs into plants, given its uniform distribution between roots and shoots for lettuce.     

Dark-Humus Residual–Hydromorphic Soils of the Slopes of the Northern Uvaly Formed on Clay Triassic Deposits

Northern Uvaly dark-humus soils and agrozems, which formed on Triassic clay deposits, are examined. Their hydromorphic nature is identified based on determination of their organic matter properties. Nonconformity of the hydromorphic features to the current moisture conditions is found, which indicates the residual character of hydromorphism and confirms the concept that the territory of the Uvaly was uplifted during the Holocene.     

Nonspecific organic compounds in peat soils of the Subpolar Urals

Specific features of organic matter, molecular composition and distribution of oxygen-containing nonspecific organic compounds (fatty acids, long-chain aliphatic alcohols, and ketones) were revealed in two peat soils on slopes of the Subpolar Urals: the eutrophic peat soil of the spring mire (Hemic Histosols) and the peat soil of a slope mire (Fibric Histosols). Compounds that can serve as molecular markers for some evolutionary stages of peats were determined for this area. Based on the data obtained, the most probable causes of differences in the composition of organic compounds in the peats studied were found to be the following: environmental conditions, water and mineral regime of bog, and differences in the composition of peat-forming plants.     

Biological mineralization of organic matter in the modern virgin and plowed chernozems,buried chernozems,and fossil chernozems

The phenomenon of mineralization (biological mineralization) of organic matter in chernozems has been studied. A decrease in the content of C_org with time can be considered an index of the organic matter mineralization. It is suggested that the humus horizons of modern chernozems contain the pools of organic matter of different ages: easily decomposable organic matter, labile biologically active humus, stable biologically active humus, and relatively inert humus. The composition and mean residence times of these pools and their contribution to the total organic matter content have been estimated. The particular types of the biological mineralization have been determined on the basis of the comparison between the velocities of mineralization (M) and humification (H) processes: total unidirectional mineralization (M ≫ H), equilibrium mineralization (M ∼ H), nonequilibrium mineralization (M> <H), and zero mineralization. The separation of subtypes is based on data on the relative rates (%) of the organic matter mineralization. On the basis of available experimental data on chernozems buried under kurgans and in loess sediments (with the age of up to 800 ka), the quantitative relationship of the humus content in the buried soils on their age has been found; it has an exponential shape. During the first 100 ka after the soil burial, the soil humus content gradually (with a slowing intensity) decreases from 100–75 to 6.5% of its content in the virgin chernozems. Then, 100–1000 ka after the soil burial, the soil humus content remains approximately constant (6.5% of the initial level, or 0.3% of the soil mass). The rates of mineralization have been estimated. It is shown that the elemental composition (C, H, N, O) of humic acids remains relatively stable for a long time due to the regeneration of the chemical structure of humus (matric restoration of humus). It is suggested that several different forms of humus related to pedogenesis should be distinguished in the biosphere. The renewable humus in the equilibrium state with the environment is typical of the open biospheric (soil) systems. The fossil humus, whose content decreases with time, and whose composition remains stable, is typical of the semiclosed and closed systems. With time, it transforms into residual humus, whose content and composition remain stable. The fossilized organic matter in the fossil soils and sediments of the past geological epochs (Mesozoic and Paleozoic) considerably differs from the renewable, fossil, and residual humus.