Assessing the physiological state of woody plants by parameters of chlorophyll fluorescence in the bark of annual shoots

The relative yield of variable chlorophyll fluorescence in the bark of annual shoots of woody plants was measured with a portable pulse-modulated fluorometer designed for this purpose at the Department of Biophysics (Biological Faculty, Moscow State University). Experiments were performed to study the response of this parameter to external influences (treatment with an herbicide, water loss, etc.). The results demonstrated the possibility of reliably recording the parameters of fluorescence in the annual shoots of various woody plants without damaging these shoots. It is concluded that measurements of chlorophyll fluorescence in the bark of woody plants can be used for analyzing changes in the physiological state of tree stands under the effects of natural and anthropogenic factors.     

Influence of silts on the growth,reproduction and chlorophyll fluorescence of <Emphasis Type=Italic>Potamogeton crispus</Emphasis> in turbid water

Turions of Potamogeton crispus were planted in several turbid waters. Some parameters of growth, reproduction and chlorophyll fluorescence were measured. The results were as follows: (1) Sprouting rates in all groups reached to 100.0% on the 17^th day. (2) The parameters of the growth (stem and leaf) and chlorophyll fluorescence (Φ_PSII, qP and qN) in 120 and 150NTU waters were inhibited heavily 60 days later, and their survival time was only 140 days. However, the plants in 30 to 90NTU waters could grow near water surface, their survival time was about 190 days. (3) After 150 days, the saturating irradiance intensity and rETR_max of the leaves in 30 to 90NTU waters markedly decreased with an increase in the amount of attached silts, and the number and fresh mass of turions (propagula) in 60 and 90NTU waters were significantly lower than the control. In summary, P. crispus in 0.7-metre-deep turbid water with suspended silts (not more than 90NTU) could sprout and grow normally, and produce the turions.     

Contrasting direct and indirect effects of warming and drought on isoprenoid emissions from Mediterranean oaks

Regional Environmental Change - The degree to which climate warming and increasing drought will alter isoprenoid emissions of Mediterranean forests remains unclear, because most studies were...     

Spatial analysis of drought severity and magnitude using the standardized precipitation index and streamflow drought index over the Upper Indus Basin,Pakistan

Environment, Development and Sustainability - Droughts are one of the multidimensional extreme events that negatively influence agriculture, water availability and food security in the World. The...     

An economic assessment of drought effects on three grassland systems in Switzerland

This paper analyzes the economic impacts of summer drought on Swiss grassland production. We combine field trial data from drought experiments in three different grasslands in Switzerland with site-specific information on economic costs and benefits. The analysis focuses on the economic implications of drought effects on grassland yields as well as grassland composition. In agreement with earlier studies, we found rather heterogeneous yield effects of drought on Swiss grassland systems, with significantly reduced yields as a response to drought at the lowland and sub-alpine sites, but increased yields at the wetter pre-alpine site. Relative yield losses were highest at the sub-alpine site (with annual yield losses of up to 37 %). However, because income from grassland production at extensive sites relies to a large extent on ecological direct payments, even large yield losses had only limited implications in terms of relative profit reductions. In contrast, negative drought impacts at the most productive, intensively managed lowland site were dominant, with average annual drought-induced profit margin reductions of about 28 %. This is furthermore emphasized if analyzing the farm level perspective of drought impacts. Combining site-specific effects at the farm level, we found that in particular farms with high shares of lowland grassland sites suffer from summer droughts in terms of farm-level fodder production and profit margins. Moreover, our results showed that the higher competitiveness of weeds (broad-leaved dock) under drought conditions will require increasing attention on weed control measures in future grassland production systems. Taking into account that the risk of drought occurrence is expected to increase in the coming years, additional instruments to cope with drought risks in fodder production and finally farmers’ income have to be developed.     

基于WRF模式的云南省干旱发生风险的预测分析

云南省作为西部大开发的典型省份之一,有着独特的自然环境和资源禀赋,但同时全省地形复杂多变且处于气候带的脆弱区,气候变率相当大.本研究在分析云南省近30年的土地利用/土地覆被变化的前提下,采用中尺度天气研究与预报Weather Researchand Forecasting (WRF)模式系统,对云南省未来40年干旱发生风险进行了预测分析.研究首先对WRF模式系统适用性进行了验证,重点分析了气温和降水两个主要干旱影响因子的未来时空变异特征.然后根据WRF模式系统的输出结果,选取了系列气象干旱指标因子,并采用综合气象干旱指数计算方法在空间和时间上对干旱发生风险进行了预测.从研究结果来看,加强对现用森林资源的保护,执行长期有效的生态工程建设,可以很大程度上减缓未来干旱发生频率.同时云南省当前“城市上山”等政策实施中也应考虑到建设用地扩张的不可逆转性,避免城市盲目上山.研究指出,未来区域发展规划应该对人为土地利用进行长期且合理有效部署,减少政策的不确定性,合理的区域发展规划是应对干旱风险的有效举措.     

Multi-GCM projections of future drought and climate variability indicators for the Mediterranean region

Future climate conditions for the Mediterranean region based on an ensemble of 16 Global Climate Models are expressed and mapped using three approaches, giving special attention to the intermodel uncertainty. (1) The scenarios of mean seasonal temperature and precipitation agree with the projections published previously by other authors. The results show an increase in temperature in all seasons and for all parts of the Mediterranean with good intermodel agreement. Precipitation is projected to decrease in all parts and all seasons (most significantly in summer) except for the northernmost parts in winter. The intermodel agreement for the precipitation changes is lower than for temperature. (2) Changes in drought conditions are represented using the Palmer Drought Severity Index and its intermediate Z-index product. The results indicate a significant decrease in soil moisture in all seasons, with the most significant decrease occurring in summer. The displayed changes exhibit high intermodel agreement. (3) The climate change scenarios are defined in terms of the changes in parameters of the stochastic daily weather generator calibrated with the modeled daily data; the emphasis is put on the parameters, which affect the diurnal and interdiurnal variability in weather series. These scenarios indicate a trend toward more extreme weather in the Mediterranean. Temperature maxima will increase not only because of an overall rise in temperature means, but partly (in some areas) because of increases in temperature variability and daily temperature range. Increased mean daily precipitation sums on wet days occurring in some seasons, and some parts of the Mediterranean may imply higher daily precipitation extremes, and decreased probability of wet day occurrence will imply longer drought spells all across the Mediterranean.     

土地利用变化及林业温室气体排放核算制度与方法实证

土地利用变化及林业(LUCF)活动是生态固碳最重要手段。研究确定LUCF温室气体排放核算制度和方法,对平衡碳排放、开展全国统一碳市场交易具有重要基础作用。在综述LUCF温室气体核算理论和方法基础上,借鉴IPCC指南和《省级温室气体清单编制指南(试行)》推荐的基本方法,构建了符合地域特色的LUCF温室气体排放核算制度和方法。采用2014年第九次国家森林资源清查数据,以全国低碳试点省陕西省为实证对象,初步核算了陕西省LUCF温室气体的净排放量,并从排放能力、排放结构和空间特征等角度揭示了陕西省LUCF温室气体的排放特征。结果显示:(1)2014年,陕西省LUCF温室气体净吸收量为1 698.42万t CO_2e,其中森林及其他木质生物质碳贮量净吸收1 852.67万t CO2e,森林转化净排放154.25万t CO_2e。(2)乔木林等优势树种,是陕西省LUCF温室气体排放中重要的固碳源(吸收源)。(3)陕南地区是重要固碳贡献区,陕北地区森林固碳能力较差。最后,针对LUCF温室气体排放核算制度和方法不够完善、森林固碳能力差异较大、区域固碳分化严重等问题,提出了健全温室气体核算制度、平衡森林资源空间分布、改善固碳树种结构等加强陕西省LUCF活动应对气候变化统计核算制度和能力建设的基本措施。     

Increasing extremes of heat and drought associated with recent severe wildfires in southern Greece

Mountains of the northern Mediterranean basin face two major threats under global change. Aridity and available fuel are both expected to increase because of climatic and land-use changes, increasing fire danger. There may already be signs of such effects in the case of the Pinus nigra and Abies cephalonica forests on Mt. Taygetos (southern Greece). We reconstructed climate (mid- to late-fire-season drought) using tree-rings for the last 150 years and compared it with the mountain’s fire history reconstructed from P. nigra fire scars. Seven, out of the ten, large fires Mt. Taygetos experienced were associated with below-normal precipitation (P) or above-normal maximum temperature (T _max). The largest fires occurred in late summer of 1879, 1944, 1998, and 2007. However, only the recent fires (1998 and 2007) had both low P and high T _max, also confirmed from long-term meteorological data. The synergy between climate and fuel availability may explain the very high intensity of 1998 and 2007 fires that burned mostly as stand-replacing crown fires. The other two large fire events (1879 and 1944) most likely occurred under reduced availability in burning fuel and were related to above-normal T _max. Our findings are among the first based on long-term and site-specific empirical data to support the prediction that Mediterranean mountainous areas will face a very large threat from wildfires in the twenty-first century, if socioeconomic changes leading to land abandonment and thus burning fuel accumulation are combined with the drought intensification projected for the region under global warming.     

Effect of heat stress on morphophysiological characteristics and biochemical parameters of stress response in gypsy moth (Lymantria dispar L.) larvae

Experiments on daily exposure of gypsy moth larvae to heat stress have shown that it leads to an increase in the survival rate of larvae with reduced adaptation to artificial diet (AD) and a decrease in the survival rate of larvae well adapted to AD. It has been found that acetylcholine esterase and tyrosinase activities and the concentration of tyrosine derivatives are reduced significantly in stress-exposed larvae. The conclusion is drawn about a possible relationship between change in the level of larval adaptation to food and a switch in metabolism of tyrosine derivatives from hormone synthesis to melanin synthesis pathway.     

Respiratory effects of household exposures to tobacco smoke and gas cooking on nonsmokers

The records of 708 nonsmoking white adult residents of Washington County, MD, who had participated in two of respiratory symptoms were analyzed to evaluate the effects of exposure at home to two potential sources of indoor air pollution: cigarette smoking by other household members, and use of gas as a cooking fuel. After adjustment for the effects of age, sex, socioeconomic level, occupational exposure to dust, and years of residence in household, the presence of one or more smokers in the household was only suggestively associated with a higher frequency of chronic phlegm and impaired ventilatory function defined as FEV₁ < 80% predicted. The use for cooking was associated with a significantly increased frequency of chronic cough and a significantly greater percentage with impaired ventilatory function as measured both by FEV₁ < 80% predicted and by FEV₁/FVC < 70%.     

A review of virus and protein sorption by ion exchange resins

This paper reviews the use of ion exchange resins for adsorbing proteins and viruses and for purifying viral suspensions. The analysis of resin performance under different conditions provides some information on the fundamental nature of virus/protein-resin interaction.A variety of systems are considered and the influence of factors such as resin type, resin pretreatment, chemical characteristics of the solution and virus type on adsorption are discussed and compared. Analogies are made between virus-host and virus-resin interactions, both of which are specific to the virus-host or virus-resin pair. Consideration is given to the use of proteins as models for virus adsorption. The use of viral parameters such as iso-electric point and the amino acid content of the protein coat for predicting virus adsorption behavior is also discussed. Anion exchange resins were found to be more effective virus sorbents than cation exchange resins. Cation exchange resins were ineffective in low ionic strength media, while anion exchange resins were most effective in low ionic strength media.     

基于混合生命周期方法的私人电动汽车温室气体排放研究

近年来,电动汽车因其在行驶过程中无任何尾气排放,被各国政府视为推动交通部门清洁、低碳发展的重要途径,主要发达国家纷纷推出了各自的电动汽车发展战略。但是,由于电力属于二次能源,其上游电力生产阶段的能源消费是否清洁将对电动汽车的减排效果产生重要影响。考虑到目前中国绝大部分电力源于煤炭,电动汽车是否真正有益于减排还有待进一步验证。目前一些专家和学者基于传统的过程生命周期评价方法对电动汽车的能源消费、温室气体排放做了一些研究,但研究结果差异较大。为了对电动汽车的减排效果进行更精确的研究,本文采用混合生命周期方法对电动汽车的能源消费、温室气体排放进行了计算。同时,在考虑电动汽车的燃料生命周期、车辆制造生命周期的基础上,将相关配套充电设施建设生命周期纳入到电动汽车的全生命周期系统边界内,以使对电动汽车全生命周期的研究结果更加完整、精确。研究结果显示,纯电动汽车并非是"零排放"的,在燃料周期,虽然纯电动汽车的单位里程能源消费强度较小,约为传统汽油车的94.6%,但以煤为主的高碳电力结构导致目前纯电动汽车燃料周期的单位里程温室气体排放强度约为传统汽油车的1.12倍;车辆周期内,纯电动汽车的能源消费和温室气体排放量也略高于传统汽油车;此外,配套充电设施的建设也将增加纯电动汽车全生命周期的能源消费和温室气体排放量。综合燃料、车辆及充电设备的全生命周期,在当前的电源结构及技术条件下,电动汽车虽然具有较高的能源效率和较好的石油替代效果,但其全生命周期内的煤炭消费较高,导致其温室气体排放量高于传统汽油车,在当前的情况下大规模发展电动汽车并不利于温室气体减排。     

Effects of atrazine and nicosulfuron on freshwater microalgae

Growth modifications caused by various concentrations of atrazine and nicosulfuron were monitored in closed and continuous culture of Chlorella vulgaris (chlorophyta), Navicula accommoda (diatomophyta), and Oscillatoria limnetica (cyanophyta). The concentration at which algal growth rate was reduced twofold (EC50) was determined in the three species for both herbicides. Comparatively, the two toxicants were applied at 10 microg/l level in microcosms inoculated with natural phytoplankton from Lake Geneva. The relative abundances of major phytoplanktonic species were measured by algal cell count at the beginning and at the end of each experiment. Atrazine and nicosulfuron have different targets in plant metabolism, respectively, photosystem II (PSII) and acetolactate synthase (ALS), and the expected effects were different. Generally, the cultured phytoplankton exhibited various sensitivities, depending on species or herbicide. In the microcosms, the major taxa of natural phytoplanktonic samples exhibited various patterns, from acute toxicity to growth enhancement. For example, the diatoms inside the community were not affected by atrazine and nicosulfuron, except for Stephanodiscus minutulus that was sensitive to both, and Asterionella/formosa that was sensitive only to nicosulfuron. The specific physiology and the relationships among the phytoplanktonic communities have to be carefully considered when one would try to predict the extent of herbicide action on natural phytoplankton using in vitro tests. There is a need to test the toxic effect on various cultured strains, representative of most of the taxonomic composition of natural communities, to take into account the wide range of sensitivities and reaction to herbicide contamination. But this is not enough to give a solid frame when transposing the results to the field, and the use of more ecologically relevant systems is recommended.     

页岩气开发对生态环境影响评价模型

针对页岩气特殊的开发方式及环评难度比常规气大的特点,运用"压力-状态-响应"框架模型,建立了页岩气开发对生态环境影响的评价指标体系。引入曲线投影的方式,并将投影寻踪方法和动态聚类方法相结合,提出了曲线投影寻踪动态聚类的定量评价方法;基于样本各指标的曲线投影和动态聚类方法寻找最佳投影方向,并建立相应的生态环境影响评价优化模型。结合全局最优经验指导和信息素交流,采用改进的蚁群算法对优化模型进行求解。该算法维持蚁群的多样性,且收敛性较好,同时也避免出现局部最优。对四川省威远页岩气区块进行了实例分析,结果表明:2010年、2011年和2014年的环评属于差类(4级),2012年和2013年的环评属于中类(3级),其中植被覆盖率、空气质量优良率、地表水质达标率、废水排放量、公众对环境的满意度、二氧化硫排放量和废水排放量达标率等指标对生态环境评价的影响较大。在页岩气开发初期,由于开发技术落后,再加上环保投资不高,环保意识不强,造成生态环境问题较为严重。随着学习借鉴美国的经验,及页岩气的开发技术进一步提高,加上国家对生态环境保护的重视,威远页岩气区块生态环境恶化得到有效的遏制。但开发时间越长,开采难度越大,将会产生更多更大的生态环境问题。分析结果与威远页岩气开发区域的实际情况相符,为页岩气气田生态环境影响评价奠定了科学基础。投影寻踪动态聚类方法具有无需设定参数、操作简单、客观等优点,是页岩气开发对生态环境影响评价的一种新方法。     

Modeling of agricultural drought risk pattern using Markov chain and GIS in the western part of Bangladesh

The aim of the study is to assess the agricultural drought risk condition in the context of global climate change in the western part of Bangladesh that covers about 45% area of the country for the period of 1960–2011. Drought Index (DI) and Drought Hazard Index (DHI) have been calculated by Markov Chain analysis and that of Drought Vulnerability Index (DVI) from socioeconomic and physical indicators. The DI values show that the northern part in general is more drought-prone, having less crops prospect, whereas the southern part is less drought-prone with high crop potentiality. The probability of extreme drought occurrence increases in recent decades in some parts as a result the drought events become more frequent in the areas. The DHI ranges from 15 to 32, and northern part suffers from more extreme drought hazards than that of southern part. DVI also indicates that northern part is exposed to high to very high drought vulnerability as higher percentage of illiterate people are involved in agricultural practices and high percentage of irrigation to cultivable land, but southern part exposed to moderate to low vulnerability because of low values of vulnerability indicators. Finally, agricultural drought exists at high risk condition in northern part and low in southern parts and 21.63, 26.54 and 29.68% of the area poses very high, high and moderate risk, respectively. So, immediate adaptation measures are needed keeping in mind climate features like rainfall and temperature variability, drought risk and risk ranking to make viable adaptation measures.     

Analysis of temperature influences on the amplitude-frequency characteristics of Rn gas concentration

The ventilation mechanism of Rn gas in underground environments is considered. Ventilation plays an important role in influencing the variability (harmonics) of Rn gas in the porous space below the earth's surface. We propose a new physical-environmental model of relating Rn gas concentrations to air temperature variations at the earth's surface. Applicability of this model was tested after searching for Rn gas indicators of geodynamic processes in two underground tunnels in central and southern Israel. The theoretical estimation of Rn gas concentrations shows a good agreement with the observed values. We demonstrate the possibility of Rn gas anomalies being caused by atmospheric temperature variations and the necessity to take these effects into account when investigating geodynamic processes.     

Study on Disturbances and Its Effects on Nature Reserves

1 INTRODUCTION Nature reserves are special regional ecological systems. They are the cornerstone for the protection of ecosystems on a global scale (Fuentes et al., 2000), and a necessary method to protect biological resource, species, and the diversity of the ecosystem (Zhang, L.Y., et al., 2002). Since the 1970s the research for designing, planning, and managing various kinds of nature reserves has seen rapid development. Many sorts of disturbance factors occurring in nature reserves, …     

Effects of brine injection wells, dry holes, and plugged oil/gas wells on chloride, bromide, and barium concentrations in the Gulf Coast Aquifer, southeast Texas, USA

Data from 1,122 brine injection wells, 24,515 dry holes, 20,877 plugged oil/gas wells, and 256 water wells were mapped with a geographic information system (GIS) and statistically analyzed. There were 9, 107, and 58 water wells within 750 m of a brine injection well, dry hole, or plugged oil/gas well, respectively. Computed median concentrations were 157 mg/l for chloride, 0.8 mg/l for bromide, and 169 microg/l for barium. The maximum chloride concentration was 2,384 mg/l, close to 10 times the secondary drinking water standard. Shallow water wells and water wells near plugged oil/gas wells had significantly higher chloride and bromide levels.