Oxidation inhibitors occuring in bioproducers, recent sediments, ancient rocks and oils

Native antioxidants (AO) are involved in the transformation of organic matter (OM) in different stages of diagenesis. In the early stages, the geochemical significance of AO can be estimated by using AO consumption index (I). The positive I values suggest that the OM fossilization proceeded under reducing conditions which favoured the formation of oil-source rocks, while the negative I values indicate oxidizing conditions which are characterized by the formation of rocks having a low oil-generation potential. In the late stages of diagenesis, the AO content is indicative of the degree of catagenic (thermal) or biodegradation (oxidative) transformation of oils. The AO contents of Paleogenic, Mesozoic and Paleozoic oils have been found to differ approximately by one order of magnitude. A major portion of AO is concentrated in oil resins and asphaltenes. The ratio of AO to resins and asphaltenes can be used as criterion of catagenic transformation of OM.     

REGIONAL CLIMATE CHANGE SCENARIOS UNDER GLOBAL WARMING IN KAZAKHSTAN

The aim of this paper is to report on the development of regional climate change scenarios for Kazakhstan as the result of increasing of CO₂ concentration in the global atmosphere. These scenarios are used in the assessment of climate change impacts on the agricultural, forest and water resources of Kazakhstan. Climate change scenarios for Kazakhstan to assess both long-term (2× CO₂ in 2075) and short-term (2000, 2010 and 2030) impacts were prepared. The climate conditions under increasing CO₂ concentration were estimated from three General Circulation Models (GCM) outputs: the model of the Canadian Climate Center Model (CCCM), the model of the Geophysical Fluid Dynamics Laboratory (GFDL) and the 1% transient version of the GFDL model (GFDL-T). The near-term climate scenarios were obtained using the probabilistic forecast model (PFM) to the year 2010 and the results of GFDL-T for years 2000 and 2030. A baseline scenario representing the current climate conditions based on observations from 1951 to 1980 was developed. The assessment of climate change in Kazakhstan based on the analysis of 100-years observations is given too. As a result of comparisons of the current climate (based on observed climate) the 1× CO₂ output from GCMs showed that the GFDL model best matches the observed climate. The GFDL model suggests that the minimum increase in temperature is expected in winter, when most of the territory is expected to have temperatures 2.3–4.5 °C higher. The maximum (4.3 to 8.2 °C) is expected to be in spring. CCCM scenario estimates an extreme worming above 11 °C in spring months. GFDL-T outputs provide an intermediate scenario.     

Early Norian flora from Partizansk River Basin of Primorye, Russia

An early Norian flora from the Partizansk River Basin of Primorye, Far-East of Russia, is described in detail for the first time, in which over 25 taxa are reported. The flora is dominated by cycadoalean, bennettitalean and coniferous plants, associated with a lot of ferns and czekanowskialean plants, and with a few ginkgoalean. In floristic characteristics, the flora can be well comparable with Late Triassic Mongugai flora of southwestern Primorye and its neighboring Tianqiaoling flora of eastern Jilin, China, as well with the Yamanoi and Nariwa floras from southwestern Japan. As the plant-bearing strata are sandwiched in the lower Norian marine beds yielding marine fauna, the age of the Partizansk flora is well evidenced as the early Norian. Paleophytogeographically, the flora appears to be in the ecotone of the Medio-Triassic and Arcto-Triassic floristic regions in Eurasia, and indicates probably warm temperate or subtropic vegetation in nature. Four new species are reported in this paper, including Ctenis elegantus sp. nov, Ixostrobus pacificus sp. nov., Elatocladus elegantus sp. nov. and E. prynadae sp. nov.     

Microbial processes and factors controlling their activities in alkaline lakes of the Mongolian plateau

A striking feature of the Mongolian plateau is the wide range of air temperatures during a year,-30 to 30°C.High summer temperatures,atmospheric weathering and the arid climate lead to formation of numerous alkaline soda lakes that are covered by ice during 6–7 months per year.During the study period,the lakes had p H values between 8.1 to 10.4 and salinity between 1.8 and 360 g/L.According to chemical composition,the lakes belong to sodium carbonate,sodium chloride-carbonate and sodium sulfate-carbonate types.This paper presents the data on the water chemical composition,results of the determination of the rates of microbial processes in microbial mats and sediments in the lakes studied,and the results of a Principal Component Analysis of environmental variables and microbial activity data.Temperature was the most important factor that influenced both chemical composition and microbial activity.p H and salinity are also important factors for the microbial processes.Dark CO 2 fixation is impacted mostly by salinity and the chemical composition of the lake water.Total photosynthesis and sulfate-reduction are impacted mostly by p H.Photosynthesis is the dominant process of primary production,but the highest rate(386 mg C/(L?d)) determined in the lakes studied were 2–3 times lower than in microbial mats of lakes located in tropical zones.This can be explained by the relatively short warm period that lasts only 3–4 months per year.The highest measured rate of dark CO 2 assimilation(59.8 mg C/(L?d)) was much lower than photosynthesis.The highest rate of sulfate reduction was 60 mg S/(L?d),while that of methanogenesis was 75.6 μLСН 4 /(L?d) in the alkaline lakes of Mongolian plateau.The rate of organic matter consumption during sulfate reduction was 3–4 orders of magnitude higher than that associated with methanogenesis.     

Chemical composition and sulfur forms in saline lakes of Kulunda Plain(Russia)

正1 Introduction On the territory Kulunda Plain,located to the south-west of the Ob’plateau,there are more than 3,000 fresh and salt lakes with water TDS range from 1 to 430 g/L.The interest in these lakes was associated mainly with the study of