Physiological Rearrangements in the Progeny of White Rats in the Zone of the Chernobyl Accident

Studies on six generations of white rats kept at the experimental station in Chernobyl showed that the dynamics of hormonal rearrangements and endocrine responses evoked by additional stress (hypokinesia) were generation- and sex-dependent. The male rats of the first five generations were characterized by hypercorticoidism, early involutional shifts, and decreased reactivity in response to hypokinesia. By the sixth and seventh generations, the hormonal profiles shifted toward an increase in the background level of sex hormones and their role in the response to hypokinesia. In female rats, the hormonal indices and reactivity changed less significantly.     

西南地区不同地形降水稳定同位素特征及其水汽来源

为阐明西南地区不同地形对于降水稳定同位素的影响以及各个水汽团在地理上的分界线,选取四川盆地、云贵高原、青藏高原东部及横断山脉3个地区共10个研究点作为本次研究的对象,分析了西南地区大气降水中δD、δ18O的时空变化特征,并初步建立了3个地区大气降水线,探讨了降水稳定同位素与温度、降水量及水汽来源之间的关系,并利用HYSPLIT4.9模型分析追踪冬夏半年降水事件的水汽来源及运移路径。结果表明：西南地区降水稳定同位素存在显著的高程效应;δ18O=-0.0028H-3.93,R=0.89,降水中δ18Ｏ和δＤ值表现出由四川盆地-云贵高原-青藏高原东部与横断山脉地区逐渐贫化的趋势,季节变化规律特征为冬半年整体偏重,而夏半年整体偏轻。同时西南地区除昆明与成都地区外,d值整体上表现出夏低冬高的特征,符合我国季风降水影响区域的特点。3处地区大气降水线（LMWL）与全球大气降水线（GMWL）相比,四川盆地、青藏高原东部及横断山脉地区斜率与截距明显偏小,而云贵高原斜率与截距偏大,其主要与水汽凝结时温度、蒸发条件、水汽来源以及输送方式有关。温度效应和降水量效应在不同地区主导性存在差异,四川盆地地区、云贵高原地区、青藏高原东部以及横断山脉地区整体上不存在温度效应,存在显著降水量效应。西南各地区主导型水汽团也存在差异性,通过对不同地区冬夏季风期间主导型水汽团初步分析,受单一性水汽团影响的区域主要分布于西南部与东北部,而受多种水汽团影响的区域主要分布于西北部与东南部;贵阳-安顺一线处于西太平洋水汽团与孟加拉湾水汽团交界处,成都-卧龙-黄龙一线处于西太平洋水汽团与西风带水汽团的交界处。 关键词： 大气降水;稳定同位素;水汽来源;不同地形;西南地区     

Radionuclides in the Ecosystem of Lake Tygish in the Zone of the Eastern Ural Radioactive Trace

The radioecological situation in Lake Tygish is described. The lake is situated on the central axis of the Eastern Ural Radioactive Trace (EURT), which was formed after the nuclear accident in the Southern Urals in 1957. The distributions of ⁹⁰Sr and ¹³⁷Cs among the main components of the water body and the results of the measurement of tritium concentration in the water are presented. Mathematical models are described that have made it possible to estimate changes in the concentrations of radionuclides and their amounts accumulated in the water and bottom sediments of the lake during the long period after the accident and to predict the development of the radioecological situation in the lake until 2057. Based on the mathematical models, more accurate data on the initial ecological situation in the lake in the year of the accident have been obtained.     

Changes in the salinity of the Euphrates River system in Iraq

The water salinity of the Euphrates River as it enters Iraq, expressed as total dissolved solids (TDS), has more than doubled compared to that of 1973. Downstream of Al Hindia Barrage, south of Baghdad, the salinity has increased gradually over the last 30 years. The annual average TDS at Al Nassiriah, in the lower reaches of the Euphrates, has increased from 1,080 ppm in 1979 to more than 4,500 ppm in 2001. Water quality of the Euphrates within Iraq has deteriorated due to the decreased flow that is entering Iraq, diverted flows to the river from Al Tharthar Lake, and irrigation-return flow. The decreased flow from upstream sources was due to reservoir construction projects. Water from Al Tharthar Lake and from irrigation return flow is being diverted to the Euphrates to compensate for the upstream deficit. An environmental flow rate of 178 m³/s (annual minimum flow, 5.6 bcm or about one-third of historic minimum flow) is proposed as the minimum discharge that must be flowing into Iraq to preserve the environment of the Euphrates River in Iraq. A flow of twice this amount would allow more reasonable downstream management with an input average salinity of 760 ppm.     

Role of the fungal mycelium in the retention of radiocaesium in forest soils

The aim of this work was to study possible binding of 137Cs to various organic components in the soil and fungi, by using various sequential extraction procedures. The retention and binding of 137Cs has been studied in two horizons Of/Oh and Ah/B of a Ukrainian forest soil. The exchangeable fractions 137Cs from soil (sum of H2O and 1 M NH4OAc fraction) were found to be 12% in the organic-rich layer (range 11-14%) and 23% in the organic-poor (range 20-29%). The hydrolysis with 10% H2SO4 resulted in an additional release of 30% of 137Cs from the organic-rich soil (range 30-35%) and 38% from the organic-poor soil horizon (range 27-53%). Extraction with 30% H2O2 released 11 and 15% of the 137Cs activity from organic-rich and organic-poor soil horizons. The corresponding values for treatment with 98.8% NaOCl were about 27% in both types of soil. About 11% of the total 137Cs activity was found in the humic acid fraction, about 5% in the fulvic fraction and 46% in the residue fraction. Relatively high level of 137Cs activity in soil (ca. 50%) was thus still left unsolved in the residue fraction. About 29% of 137Cs activity concentration in fungal mycelia was found as water soluble with a range of 11 to 41%. Additionally 24% of the 137Cs activity from mycelia was released by 1 M ammonium acetate extraction. Together, water and 1 M ammonium acetate extraction released about 53% of the total 137Cs activity in the mycelia. In fruit bodies of mycorrhizal fungi, 68% of the total 137Cs inventory was found to be water soluble at room temperature and 93% at 80 degrees C.     

Radionuclides in terrestrial ecosystems of the zone of Kyshtym accident in the Urals

It was shown that along the Eastern Ural Radioactive Trace central axis, about 100 km in length, decrease of the ⁹⁰Sr and ¹³⁷Cs deposition densities in soil samples may be described as an exponential function. At the western and eastern periphery of the trace, ⁹⁰Sr contents in soils approached to the background level due to global fallout. ⁹⁰Sr and ¹³⁷Cs concentrations in seeds of some herbaceous plants have been determined. The radionuclide concentrations and the resulting dose loads upon plant seeds showed an excess over the background level of about two or three orders of magnitude.     

Changes in the ratio of plants with different mycorrhizal status in the course of pasture digression in the Southern Ural steppes

Trends in the proportions of plants differently interacting with mycorrhizal fungi in the course of pasture digression have been analyzed in the steppe zone of the Southern Urals. Estimates of species richness and abundance of plant groups with different mycorrhizal status have been obtained by comparing original data on the structure of phytocenoses with published data on the ability of plant species to form mycorrhizae. It has been shown that the proportions and abundance of obligate mycorrhizal species decrease significantly in the course of digression, with consequent increase in those of species less dependent on or independent of symbiosis with fungi, i.e., facultative mycorrhizal or obligate nonmycorrhizal plants.     

Zonal patterns in the formation of synanthropic vegetation in the city of Kursk

Analysis of zonal patterns in the formation of synanthropic vegetation has shown that the intensity of manifestation of its zonal differentiation increases with the advancement of the successional stage of synanthropic communities. The rate of successional processes in these communities depends on the initial (potential) type of vegetation in the territory of the city.     

On the Multifunctional Role of the Biota in the Self-Purification of Aquatic Ecosystems

Principles of the theory of the ecological mechanism of water self-purification based on multiple functions of the biota in freshwater and marine ecosystems are formulated. In developing this theory, the results of the author's experiments with filtering hydrobionts have been used. These results indicate that the water self-purification mechanism is vulnerable to the impact of some pollutants and, in particular, surfactants. Conclusions drawn on the basis of the theory have practical significance for biodiversity conservation and for the sustainable use of the biological resources of aquatic ecosystems.     

我国减缓碳排放的近期形势与远期趋势分析

近3年来我国面临GDP能源强度呈上升趋势，能源消费及相应CO2排放增长对世界减缓碳排放的形势产生了更大影响的新的形势，从长远发展趋势看，我国当前由于工业特别是重化工业在国民经济结构中急剧增加引起的GDP能源强度阶跃性增长将随产业结构的稳定两平缓，并且随产业结构的优化和产业技术升级及高附加值产品比例提高而再度呈持续稳定下降的趋势。我国在现代化道路中与发达国家的历程相比，可以走更为节约能源和减少CO2排放的道路。但由于中国人口众多，和平发展的规模大、速度快，而且时间比发达国家滞后半个世纪以上，我国为实现现代化所必需的能源消费和CO2排放的增长会对全球的碳排放增长产生重大影响。这将使我国未来经济发展面临极为不利的外部环境。     

Factors of variation in the number of adventive species in herbaceous communities of the Western Caucasus

The saturation of herbaceous communities with adventive species in the Northern Caucasus has been estimated using as an indicator the number of such species in 0.5-m² plots. Among factors accounting for variation in the test parameter, consideration has been given to the coverage of the herbaceous layer, the species richness of communities (in 0.5-m² plots), and the numbers of adventive and indigenous species (in 15-m² plots). The field data have been processes by methods of ordinary and multivariate regression analysis. The results show that variation in saturation with adventive species between small areas of herbaceous communities largely depends on the number of such species in larger areas, their species-holding capacity, and the level of completeness of communities.     

Distribution of 137Cs in the Tree Layer of Forest Ecosystems in the Zone of the Accident at the Chernobyl Nuclear Power Plant

Trends in ¹³⁷Cs distribution over the parts of coniferous (Pinus sylvestrisL.) and deciduous (Betula pendula Rocht.) trees are described. The trees have been selected in the stationary experimental plots located in southwestern Bryansk oblast, Russian Federation. The distribution of ¹³⁷Cs in the wood along the trunk height is shown to be nonuniform. The effects of ¹³⁷Cs content in the xylem sap on the accumulation of this radionuclide in the leaves and needles are assessed. The factors controlling ¹³⁷Cs accumulation in the components of woody plants are revealed, and their significance is estimated.     

Fluctuations in the size of Lake Chad: consequences on the livelihoods of the riverain peoples in eastern Niger

Recent level changes in Lake Chad are associated with large area changes because the lakebed is almost flat. They have deeply impacted the lifestyle of local populations. The Mober are the main ethnic group living in the surroundings of Bosso, in eastern Niger near the Yobe River and in Lake Chad. They were initially herders and farmers who developed flood-retreat farming and sophisticated irrigation systems. But their main activity during high Lake levels was fishing: it provided food as well as substantial incomes, thanks to the export of smoked and dried fish. Since 1973, Lake Chad has shrunk, mainly because of the decrease in rainfall in its southern hydrological basin, on the border between Chad and the Republic of Central Africa. On the border between Niger and Nigeria, the Yobe River discharge was more stable but it provided a minor input to the Lake. Large areas with rich soils, termed here as polders by analogy with those of the Bol region in Chad, became available and allowed maize, cowpeas, sorghum and vegetables farming without irrigation or fertilizer. This system is governed by the “bulama,” chiefs of the villages and of the land that is still abundant. However, without any return of the Lake on the polders, there is a serious risk of soil exhaustion. Sweet pepper farming has been developed on the sandy Yobe borders since 1960, partly thanks to the local farmers’ ancient knowledge of irrigation techniques. It requires an investment of capital to buy fertilizers, pesticides, and gasoline for the motor pumps. This farming system may not only provide high incomes, but it also promotes inequality between men and women on the one hand and on the other hand, between poor farmers, who must borrow money and who have to sell their harvest immediately, and those who are able to store their products and wait for the best prices. The Mober of Bosso were able to adapt to rapid changes in the level of the Lake firstly without public intervention due to their long-lasting pluriactivity. However, their ability to cope with stronger changes induced either by climate or by large projects aiming at restoring high Lake Chad levels should be carefully monitored.     

Response of lithophilic zoobenthos to changes in the granulometric composition of grounds in the metarithral zone of a small river in the foothills of southwestern kamchatka

Data on the species composition, abundance, and biomass of macrozoobenthos in the rapids of a small river flowing in the foothills of the southwestern Kamchatka Peninsula are considered along with the results of quantitative analysis of structural rearrangements in the lithophilic community under the effects of changes in the granulometric composition of bottom sediments. Groups of lithophilic and pelophilic invertebrates typical of the metarithral of such rivers (e.g., chironomids of subfamilies Diamesinae and Prodiamesinae) are identified.Translated from Ekologiya, No. 2, 2005, pp. 120–125.Original Russian Text Copyright © 2005 by Leman, Chebanova.     

Understanding the impact of hydropower developments in the context of upstream–downstream relations in the Mekong river basin

Hydropower developments along the main stem of the Mekong River and its tributaries cause transboundary effects within the Mekong Basin Region, which comprises parts of six countries. On the one hand, the provision of hydropower triggers economic development and helps to meet the rising energy demand of the Mekong riparian countries, especially China, Thailand, and Vietnam. On the other hand, the negative impact of dam construction, mainly altered water flow and sediment load, has severe impacts on the environment and the livelihoods of the rural Mekong population. Several discrepancies exist in the needs, demands, and challenges of upstream versus downstream countries. Against the common apprehension that downstream countries are powerlessly exposed to mainly negative impacts whereas upstream countries unilaterally benefit from hydropower, the authors argue that upstream–downstream relations are not really clear-cut. This conclusion is based on a consideration of the complex power play between Mekong riparians, with a focus on recent power trade interactions. The article investigates the consequences of hydropower dams for the Mekong region as well as the role of supranational players, such as the Mekong River Commission and the Greater Mekong Subregion Initiative, on the hydropower debate. It is not nations that are the winners or losers in the hydropower schemes in the Mekong, but rather parts of the riparian population: a few influential and powerful elites versus the large mass of rural poor.     

Ecological Variation in the Morphological Structure of the Crown in Siberian Stone Pine at the Timberline

The structure of the crown and branching; the growth, development, and ontogeny of branches; and organogenesis and growth of female shoots in the model Siberian stone pine trees were studied in four types of habitats at the timberline in the central Altai Mountains (1700–2170 m a.s.l.). The results provided evidence that the ecological forms of trees appear due to changes in the pattern of branching as well as to the decreased rate of vegetative (primarily apical) growth. The diameter of the shoot pith is one of the most variable characters reflecting the deterioration of environmental conditions at higher elevations.     

Siberian musk deer in the diets of tiger and bears in the Sikhote-Alin

The role of the Siberian musk deer in the diets of the Amur tiger, brown bear, and Asian black bear has been studied in the Sikhote-Alin State Biosphere Reserve in 1992 to 2016. Information has been collected from 763 tiger feeding sites, and the contents of tiger feces have been analyzed. Radiotelemetry has been used to evaluate tiger–musk deer relationships. The musk deer accounted for 0.26% of all animal species found to be eaten by the tiger. Musk deer remains in feces of the tiger, brown bear, and Asian black bear occurred with frequencies of 1.3, 0.2, and 0.3%, respectively. A case of musk deer avoiding the presence of brown bear is described.     

Ecogeographic variation in the generative organs of larch in the Russian Far East

Relationships between morphological characters of the generative organs of larch and ecogeographic and climatic factors in the Russian Far East have been analyzed. It has been shown that local ecological factors have an effect on metric morphological characters of cones such as the length, width, and number of seed scales, which are not usually used as diagnostic characters. On the other hand, a major proportion of variation at the regional level in characters regarded as taxonomically significant is accounted for by geographic and climatic factors of the environment.     

Environmental implications of changes in the levels of lakes in the Ethiopian Rift since 1970

The Ethiopian rift is characterized by a chain of lakes of various sizes and hydrological and hydrogeological settings. The rift lakes and feeder rivers are used for irrigation, soda extraction, commercial fish farming, and recreation, and they support a wide variety of endemic birds and wild animals. The levels of some of these lakes have changed dramatically over the last three decades. Lakes that are relatively uninfluenced by human activities (Langano and Abaya) remain stable except for the usual inter-annual variations, strongly influenced by rainfall. Some lakes have shrunk due to excessive abstraction of water; others have expanded due to increases in surface runoff and groundwater flux from percolated irrigation water. Lakes Abiyata and Beseka, both heavily impacted by human activities, show contrasting lake level trends: the level of Abiayata has dropped by about 5 m over three decades because of the extraction of water for soda and an upstream diversion for irrigation. Beseka has expanded from an area of 2.5 to 40 km² over the last three decades because of increased groundwater inputs from percolated irrigation water. Lake Awassa has risen slightly due to land use changes resulting in increased runoff in its catchment. This paper addresses these lake level changes and their environmental repercussions, based on evidence from hydrometeorological records, hydrogeological field mapping supported by aerial photography and satellite imagery interpretations, water balance estimation, and hydrological modeling. A converging evidence approach is used to reconstruct the temporal and spatial variations of lake levels. The results reveal that the major changes in the rift valley are mainly related to anthropogenic factors. These changes appear to have grave environmental consequences for the fragile rift ecosystem. These consequences demand the very urgent implementation of integrated basin wide water management practice.