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干旱区绿洲棉田土壤CO2/N2O排放特征及减排潜力研究
No full text农田生态系统作为温室气体排放源之一在全球碳氮循环中起到了重要作用。新疆绿洲农田是干旱区典型的灌溉农田生态系统，受人类活动的强烈影响，农田土壤CO2/N2O排放强度远高于同区域的其他生态系统，研究绿洲农田土壤CO2/N2O排放特征及调控措施具有重要的理论及实践意义。论文以干旱区绿洲棉田为研究对象，采用静态箱-气相色谱法阐明了绿洲棉田土壤CO2/N2O排放特征及主要影响因素，假设覆膜增加了土壤CO2排放、减少了土壤N2O排放，施肥促进了土壤CO2/N2O排放；大田和培育试验相结合探明了不同管理方式下棉田土壤CO2/N2O减排潜力，假设分期施肥降低了土壤CO2/N2O排放；基于DNDC模型提出了实现绿洲棉田土壤CO2/N2O减排的优化管理模式，预测了未来气候变化对棉田土壤CO2/N2O排放的影响，为干旱区绿洲农业生产管理和温室气体减排提供科学依据。主要结论如下：（1）绿洲棉田土壤CO2排放高峰期发生在棉花生长的花铃期（7-8月）。土壤CO2排放速率随温度升高呈指数增加，过高或过低的土壤含水量下土壤CO2排放速率均较低。全生育期内，58-77%的土壤N2O排放发生在滴灌施肥期（7-8月），土壤温度、湿度和矿质氮含量增加均利于土壤N2O产出与排放。较高的土壤温度和滴灌施肥措施可增加土壤硝化和反硝化细菌活性，利于土壤硝化和反硝化过程产出和排放N2O。（2）覆膜对土壤CO2和N2O排放的影响机制不同。覆膜保温保湿促进棉花生长，利于自养呼吸产出的CO2通过膜间土壤排放到大气中，土壤CO2排放量可增加7-9%。覆膜既能提高植物氮素利用效率减少土壤N2O产出，也可抑制土壤N2O传输利于N2O还原，全生育期土壤N2O排放量可减少19-28%。（3）施肥显著促进土壤CO2/N2O排放。土壤CO2排放量随施氮量增加呈线性增加，可能是施肥促进了棉花生长，增强了土壤微生物活性，利于土壤自养呼吸和异养呼吸产出和排放CO2。施氮肥为土壤微生物的硝化和反硝化过程提供底物，土壤N2O排放量随施氮量增加呈线性增加。观测期内，土壤N2O排放系数范围为0.28-0.70%，表明采用IPCC推荐的N2O排放系数（1%）会高估新疆干旱区绿洲膜下滴灌棉田土壤N2O排放量约一倍左右。 （4）培育试验中，分期施肥和施用硝化抑制剂均有效减少了土壤CO2/N2O排放，但分期施肥方式降低了施用硝化抑制剂下土壤N2O减排效率。田间试验中，施用硝化抑制剂没有显著影响滴灌施肥棉田土壤CO2排放，但抑制土壤铵态氮转化为硝态氮的硝化过程，土壤N2O排放量可减少23-42%。施用硝化抑制剂对棉花产量没有显著影响，降低土壤N2O排放产生的碳交易收益（6-11 RMB ha-1）远低于硝化抑制剂的成本投入（150 RMB ha-1），该方法不适用于减少新疆绿洲棉田土壤CO2/N2O排放。（5）DNDC有效模拟了覆膜对棉花生长和土壤CO2/N2O排放的影响。优化管理模式下模型模拟的结果表明，覆膜使棉田灌溉量和施氮量分别减少120 mm和10 kg N ha-1，使棉花产量、土壤CO2排放量和土壤有机碳增量分别增加了9%、10%和4%，使土壤N2O排放量减少了4%。不同气候变化情景下的模拟结果表明，未来气候变化使膜下滴灌棉田的棉花产量、土壤CO2排放量和作物经济收益分别增加了5-6%、7-9%和9-10%，土壤N2O排放量和棉田土壤有机碳增量分别减少了9-15%和21-29%。总之，未来气候变化利于新疆绿洲棉花增产，对土壤CO2/N2O排放产生的增温效应影响不大
新疆城市经济效率研究
No full text在过去一段时间内，新疆城市经济保持了高速增长，取得显著成绩，已成为新疆区域经济发展的主导力量，但高速发展的同时带来过度的资源消耗和严重的环境污染，对经济可持续发展造成重要影响。在经济新常态下，新疆城市资源环境约束日益趋紧，传统经济增长动力逐渐减弱，原来的高速发展模式难以为继，亟需转变经济发展方式，实现从要素推动转向创新驱动，不断提升城市经济效率，促进新疆城市经济高质量增长，为实现新疆社会稳定和长治久安奠定坚实的物质基础。提升经济效率是城市经济社会发展的必然选择，也是促进城市可持续发展的重要途径，国内外学者从不同的角度对城市经济效率进行了评价，但多数以传统的投入和产出要素为基础评价城市经济效率，较少考虑到影响城市可持续发展的资源和环境要素，无法客观真实地反映城市经济效率。本文把资源环境要素纳入经济效率分析框架，运用非参数方法测量资源环境约束下的新疆城市经济效率，明确各城市的经济效率状态，分析各城市经济效率差异，总结城市经济效率时空演变特征，检验城市经济效率收敛性，识别城市经济效率的重要影响因素，提出改善新疆城市经济效率的建议。研究内容和主要结论如下：运用 SBM 模型（Slack Based Measure）和 ML 指数（Malmquist-LuenbergerIndex）分别评价新疆城市经济技术效率和经济全要素生产率，研究结果发现：（1）新疆城市经济技术效率平均值为 0.61，整体处于中等水平，要素投入和环境污染都造成效率损失，说明新疆城市经济发展是高投入、高消耗、高污染的粗放式发展方式，经济增长具有不可持续性。（2）新疆城市全要素生产率指数平均值为 0.98，年均增长率为-2%，呈微弱下降趋势，反映出科技创新和技术进步还没有成为新疆城市经济增长的主要动力，经济增长主要靠要素驱动和投资驱动，还没有转向创新驱动，经济增长质量不高。（3）城市经济效率存在显著区域差异和规模差异。天山北坡和天山南坡城市的经济技术效率和经济全要素生产率平均值都高于其它区域城市，大城市经济技术效率和经济全要素生产率平均值高于中小城市，说明新疆城市经济发展差距较大，存在不平衡、不协调问题。（4）随着时间的推移，新疆城市经济技术效率总体处于下降的变化趋势，出现平稳型、上升型、下降型和波动型四种演变类型，反映新疆城市经济发展出现“分化”现象。新疆城市经济全要素生产率呈现出明显的阶段性变化特征，总体表现为 “三起三落、两峰值”特点，其变化与国家经济环境、宏观政策走向紧密相连，反映新疆城市经济易受外在环境影响，经济增长不够稳定。（5）城市劳动力、资本要素投入过多，土地、水资源消耗过快，工业污染过度排放，都导致经济效率损失，影响整体经济效率，说明新疆城市在降低资源消耗、减少环境污染、提高要素生产率等方面有较大的改善潜力。根据收敛理论和方法，本文采用多种收敛方法对新疆城市经济效率进行全方位检验，分析在 2000-2015 年间新疆城市经济效率差距的现状和演变趋势。研究结果发现：（1）新疆城市经济效率不存在绝对收敛，意味着城市之间还没有出现追赶效应，城市经济效率差距会进一步扩大。然而，城市经济效率存在条件收敛，各个城市经济技术效率和全要素生产率趋向自身稳态的水平。（2）新疆城市经济技术效率不存在随机性收敛，表明着经济技术效率差距不会短期消失，而会长期客观存在。（3）新疆城市经济效率核密度分布分析发现，城市经济技术效率差距增大，城市经济全要素生产率出现两极分化现象。马尔科夫转移矩阵分析发现，新疆城市经济效率流动性较低，存在一定集聚现象，形成低经济效率、中低经济效率、中高经济效率和高经济效率的集聚现象。结果进一步说明新疆城市经济效率不存在收敛特征，城市经济效率无法实现协调发展。运用空间面板模型对城市经济效率影响因素进行计量检验，研究结果发现：（1）基础设施、城市化水平、产业结构、集聚程度对城市经济效率有显著的正向影响。说明完善的基础设施、较高的城市化水平、合理的产业结构都能够提升城市经济效率，促进城市经济发展。（2）开放水平对城市经济技术效率起着一定促进作用，但是对经济全要素生产率影响不显著。（3）人力资本和研发投入对城市经济技术效率和经济全要素生产率都没有产生显著影响，说明人力资本和研发投入还是新疆城市经济发展的短板，这两个因素还没有发挥重要作用。根据以上研究结果，本文提出了提升新疆城市经济效率的建议：完善基础设施，提升经济支撑能力；调整城市产业结构，促进结构优化升级；促进土地集约化利用，提升城市集聚水平；加快人口聚集，提高城市化水平；提高人力资本水平，提升城市竞争力；扩大开放度，建立开放型经济；加大研发投入，提高科技创新水平等。本文研究丰富和完善了城市经济效率研究内容，对定量评价资源环境约束下的城市经济效率提供了理论方法和分析框架，有助于客观真实地分析城市经济增长质量，对新疆城市转变经济增长方式，降低资源消耗，减少环境污染，提高经济效率，促进城市经济可持续发展等方面具有一定指导意义
不同寄主来源的棉铃虫种群发生和交配过程模型模拟
No full text“Refuge” strategy was widely used in Xinjiang to delay the resistance problem of Helicoverpa armigera. The basis of successfully using this strategy is to take some suitable optimizing measures for refuges in some time. Population dynamics from different host plants and critical affecting factors in different periods, and the ranges of effective mating frequency are still lack of further and systematic study, which are even so important for the refuge optimization. In this study, through the laboratory experiments, isotope techniques and population modelling simulations, the field population dynamics and mating processes were simulated to determine key factor(s)affected population dynamics and ranges of effectiveness mating frequency of cotton bollworm from different host sources, and the goal is providing some useful suggestions for refuge optimization. Some of main results are as follows:(1) Mating frequencies of Helicoverpa armigera with different physiological ages Combinations of adults population mating with different ages were made and the experiments results found that the females in random mating was a determined role influencing mating frequencies. Mating frequencies of the 0-2 instars’ female were generally higher than others, and the average mating ratios were more than 60%; The females still had high potential mating abilities when ages were less than 5 instars, and average ratios exceeded 20% comapring to the females with 5~8 instars; In this study, the influence of the males' age was not significant in the mating frequency. (2) Modelling Simulations of Helicoverpa armigera using DYMEX and contributions analyses of key factors Establish DYMEX model could accurately simulate the field population dynamics of cotton bollworm（R2>0.4，P<0.05）. The effects of pesticides and natural enemies units in controlling the pest and contribution rates of interpreting variations of population dynamics were analyzed. The pesticide spraying events in controlling the first and second generations of eggs and larvae were pronounced, and average variation accounted for about 40%, but contribution rates of explaining population changed were declined when the third time pesticide spraying events happened; the effects of natural enemies in affecting the population decline rates were relatively stable, and the average contribution rates functioned by parasitoid and predator enemies units were 27% and 17%, respectively; The effects of interactions (insecticides and natural enemies) in negative affecting the eggs and larvae population, which trended to shrink in interpreting variations of population dynamics, except the first generations.(3) Mating process of cotton bollworm from different host sources Based on the isotope data, the population dynamics of cotton bollworm from different host plants were analyzed, which was also used to valid the simulating results. And there were generally consistency between the isotope and simulations results. According to the mating frequencies experiments’ results of cotton bollworm and the proportion dynamics of population from different host plants, the theoretical mating frequencies were calculated and ranged from 0.2 to 0.51 happened among different pest sources mating. The changing rates of mating frequencies with time were estimated. Different patterns of refuges had been simulated to know how it affected the mating frequencies, and found that the refuge size (able to supply C4 sources population) and synchronism between C3 and C4 in emerging adults for mating.(4) Simulating resistance management affected by changes of effectiveness mating frequencies Host transfer affected mating frequencies significantly when the mating processes happened between different pest sources in landscape scale, and the phenology and population density were important. And the simulations indicated that the effectiveness mating frequency ranged from 0.1 to 0.37. For the relationship between population dynamics and mating processes,, the timing of mating sooner or later would affected the population growth, and population growth rate would be decreased with the gap of adults peak periods increasing. The proportions of each kind of genotype had been calculated and their changes simulated. And the patterns of refuge such as the areas and distributions needed to consider the planting proportions and spatial layout of Bt cotton.So far, the established DYMEX model could simulate the field population dynamics under complicated conditions, which was useful for the comprehensive management, agricultural production activities and et al. Understanding mating processes of cotton bollworm was a good way of “Refuge” optimization. Mating processes happened among different pest sources were known after simulations under different “Refuge” modes, theoretically understanding the field resistance of cotton bollworm population dynamic of mating and evolutionary processes.Above all, this research solved the problem of determining effectiveness mating frequency ranges, which can optimize the establishment of “Refuge” in the future.And this also a valued job in providing some management references of delaying resistance and prolong the service life of Bt cotton
沙拐枣光合生理特性的比较研究
No full textSpecies of Calligonum L. in Turpan desert botanical garden of Chinese Academy of Sciences Institute of Xinjiang Ecology and Geography were chosen as research materials confirmed by consulting specimen and relevant literature information. Their photosynthetic characteristics, physiological indicators, element contents were measured and analyzed through the mean variance analysis and the principal component analysis. All these results could supply theoretical basis for the protection, restoration and reasonable utilization of Calligonum L. The results of the study were as follows:(1) There were significant differences between genus Calligonum species. Survey of 4 species’ daily variation of net photosynthetic rate (Pn) of Calligonum L. showed that C. calliphysa, C. Leucocladu and C. Klementzii were “double peaks” and C. ebi-nurcum was “single peak”. The influencing factors of photosynthetic rate to C. calliphysa, C. Leucocladu and C. Klementzii were mainly composed of non-stomatal factors.(2) The photosynthetic characteristics of 4 Calligonum species were examined and analyzed by the modified rectangular hyperbola model. It revealed that C. ebi-nurcum was plant with high Pn and transpiration rate (Tr), C. ebi-nurcum had higher maximum net photosynthetic rate (Pmax), light saturation point (LSP) and large range of light adaptation which showed well adaptability to the environment. C. calliphysa had the highest water use efficiency (WUE), low transpiration rate, low photosynthetic rate, low stomatal conductance and high stomatal limitation(Ls), and this can explain that C. calliphysa enhance water use efficiency to adapt drought stress by reducing stomatal conductance to reduce transpiration rate. Moreover, the lowest apparent quantum yield (AQY) and highest light compensation point (LCP) were observed in C. calliphysa which seemed to be the low utilization of light. C. Leucocladu had highest AQY and lowest LCP value which showed the efficient use of weak light, while the photosynthetic rate sharply drop at noon influenced by non-stomatal factors. C. Klementzii was poor adaptability to the drought environment with low WUE, Pmax and light utilization range. These analysis results were highly conform to the ecological distribution of genus Calligonum in Xinjiang.(3) 10 Calligonum species were selected to study the differences of physiological characteristics of Calligonum species under the desert habitat. 7 physiological indexes were measured, the differences were analyzed by variance analysis, and resistance was comprehensively evaluated by principal component analysis. The results showed that the physiological indexes in the same habitat were significantly different (P C. ebi-nurcum > C. densum > C. leucocladum > C. klementzii > C. cordatum > C. rubicundum > C. arborescens > C. caput-medsae > C. pumilum. Calligonum have different resistance mechanisms with different content of protective enzyme. The results were very anastomotic with ecological distribution of Calligonum in Xinjiang. The experiment could provide scientific basis for introducing, cultivating and screening desert plants of Calligonum in resistance.(4) The analysis of element contents of 10 Calligonum species showed that the distribution of nitrogen (N) phosphorus (P) and kalium (K) was inequality in different Calligonum species which dues to the selective absorption. The contents of N was highest in C. arborescens, lowest in C. rubicundum, and all 10 species were below the average level of China 20.2 g/kg, the global average 20.6 g/kg and the north desert level 24.4 g/kg. The contents of P was highest in C. densum, lowest in C. pumilum, and 5 species were below the average level of China 1.46g/kg, and 8 species were below the global average 1.99 g/kg. The contents of K was found highest in C. rubicundum and lowest in C. rubicundum. These revealed that C. arborescens could better use N element, C. densum had high utilization of P, while C. rubicundum made efficient use of K.(5) The ratio element content between ten Calligonum species also showed significant difference. The N/P ratio was found highest in C. pumilum and lowest in C. densum and C. cordatum. The N/K ratio was found higher in C. arborescens, C. calliphysa, C. pumilum and C. caput-medusae, while lower in C. leucocladu, C. rubicundum and C. Cordatum. C. leucocladu and C. rubicundum had highest K/P ratio while C. densum had the lowest. This study suggested that genus Calligonum in Turpan desert botanical garden were easily affected by N limitation. Especially for nitrogen deficiency in Xinjiang desert, introducing, cultivating and screening Calligonum specie with efficient absorption and utilization of N, high efficiency of photosynthesis and high adaptation to stress is very important.Key words: Calligonum L.; Photosynthesis; Resistance index; Ecological stoichiometry
自驾游服务体系构建与实证研究——以新疆维吾尔自治区为例
No full textThe era of automobile popularization, the era of mass tourism, and the era of ‘Internet +’ contribute to the development of car tourism in China which has become an important force in the national economy. This paper is to clarify the relationship between driving the elements of tourism service system, constructs the theoretical framework of driving tour service system, by comparing the domestic and foreign theoretical and empirical research. Therefore, the construction of driving tour service system is very important from the theoretical and practical perspectives. The first part studies the basic elements of driving tour service system. From the perspective of system theory, this part grasps the whole service system of driving tour, sorts out the components and parts, including driving area, driving circuit, driving camp, information service platform and the security and support services, and establishes car tourism service system based on service function and level.The second part does empirical research on evaluation index system. By the questionnaire and statistical analysis, tourist satisfaction is studied. Through exploratory factor analysis, confirmatory factor analysis and structural equation model, the highest of the elements are classified, including tourism facilities and service factor, environment factor, accessibility factor and tourism resources factor. Finally, the structural equation model of driving tour satisfaction is constructed.The third part puts forward suggestions to guide and promote driving tourism industry development through providing a theoretical basis
能源与环境约束下的新疆经济增长效率估算及其驱动因素研究
No full textResearch on the source of economic growth is one of the key issues in the studyof macro economics and regional sustainable development. Total factor productivity isan important tool to analyze the source of economic growth, and the result of which isan important basis for the government to formulate long-term economic growth policy.Meanwhile, total factor productivity is an important index to measure the quality ofeconomic growth of a country or a region, and it is also one of the important goals ofeconomic growth. With China’s economy entered the new normal period, andeconomic policy adjustment and industrial restructuring, it will become an importantissue to improve its own economic growth for Xinjiang about how to achievesustainable development under the constraints of energy and environment.This study estimates the efficiency of economic growth under the constraints ofenergy and environment, and analysis of the source of economic growth in Xinjiangby means of econometric methods. The main contents of the research include: Basedon the relevant data of Xinjiang, (1) By the grey relational analysis model, the paperanalyzes the correlation between industrial energy consumption and economic growth,as well as between energy consumption categories and economic growth in Xinjiang.(2) To confirm the existence of the environmental Kuznets curve (EKC) in Xinjiang,and to analyze the interactive relationship between environmental governance andeconomic growth. (3) By constructing a data envelopment analysis (DEA) model tomeasure the economic growth efficiency of Xinjiang, which includes energy input andnon expected output. (4) Using Solow residual method to estimate the total factorproductivity of Xinjiang, and explore the source of economic growth in Xinjiang.Above research shows: Firstly, the economic growth of Xinjiang is driven byfactors, which has strong dependence on capital, labor and energy，and there is acertain degree of irrational on energy consumption structure. Secondly, theenvironmental quality of Xinjiang is still declining, which has a certain distance to achieve EKC inflection point; meanwhile the main source of pollution is the primaryindustry and the second industry, and there is a mutual promotion between the thirdindustries and the environment. Thirdly, the economic growth of Xinjiang is facingthe dilemma of low efficiency and three structural shocks. Fourthly, the total factorproductivity of Xinjiang has a strong accumulation and path dependence. Technologytransfer and transformation are the main reasons for the change of total factorproductivity, while the impact of institutional improvement and the development ofindependent research on the total factor productivity of Xinjiang is not obvious.Fifthly, the institutional development of Xinjiang is not complete, there are manyfactors that hinder the optimal allocation of production factors, and the R&Dinvestment of Xinjiang is low, which has not yet formed a scale effect.Therefore, in the future, Xinjiang should increase investment in the environment,science and technology, education and human capital, and improve the efficiency ofenergy utilization and energy consumption structure, at the same time, effective fiscaland tax policies should be adopted to promote dynamic transformation of economicgrowth and transformation and upgrading of industrial structure, in order to realizingthe coordinated and sustainable development of economy, energy and environment inXinjiang
气候变化对印度河上游流域水文水资源变化的影响，巴基斯坦
No full text喜马拉雅山、喀喇昆仑山和兴都库什山的冰川有着复杂的动力学作用，近几十年来经历了保持稳定或扩张。然而，世界各地的冰川正在迅速退缩。这种现象称为喀喇昆仑异常。该地区拥有世界上除了极地以外最大的冰川和冰盖，被称为世界第三高峰。季节性的冰川积雪融水在为下游的居民提供水资源的山地生态系统中扮演着重要角色。在随着喀喇昆仑山冰川融化出现的众多问题中基于水文模型的积雪覆盖动态变化模拟对巴基斯坦吉尔吉特-巴尔蒂斯坦地区水资源管理有着重要意义。精确的山区降水估算对许多水文过程至关重要，例如冰川物质平衡，河流径流，干旱和洪水监测等。在复杂山区，是很难获得准确的降雨量数据。但是，卫星降水量产品可以作为这些地区降雨估算的备用数据源。全球覆盖的高时空分辨率卫星降水数据已经用于许多研究领域。因此，在研究区可用的冰川物质平衡，雪盖动力学以及降水空间格局的背景下，重要的就是河流径流的测量。将 SWAT 模型结合温度指数和高程分带算法应用到以冰川融雪水位主要水源的罕萨流域。本文利用 SWAT 模型模拟了冰川积雪覆盖度高的罕萨流域的径流量对未来气候变化的响应及其对印度和水系时空特征的贡献。模型以 1998-2004 年为校准期，以 2008-2010 年为验证期，并以 4个推荐的统计参数（p 因子和 r 因子）作为不确定性评价指标进行模拟。模型模拟结果较好，校准期和验证期的评价指标分别为 R2 系数为 0.82，Nash 系数为 0.8，P 因子为 79% R 因子为 76%。本文利用 IPCC 第 5 次报告中的 GCMs（General Circulation Models）数据，以 1980-2010 为基准期，预测了未来 2030-2059 和 2070-2099 两个时间段的径流量。结果显示，到本世纪末气温增高 1.39 °C 到 6.58 °C，降水量降水增加 31%，导致径流量增加 5%到 10%.积雪动态变化分析采用的是 MODIS 8 天合成的积雪覆盖数据，以此来与印度河上游高纬度地区的 4 个气象站的 2000 年到 2014 年的数据进行对应。结果表明，巴基斯坦吉尔吉特-巴尔蒂斯坦地区的积雪覆盖面积从 45.04%增长到 59.26%。通过 15 年的观测数据可以看出兴都库什山和喜马拉雅山的积雪覆盖面积有轻微的减少趋势，主要是因为降水和温度的增加。实测的水文气象数据，大地测量数据和卫星数据表明喀喇昆仑山西部冰川自 1990 年以来具有保持稳定或扩张的趋势。罕萨河流量从 1966到 2010 年的六月至九月减少的现象可以解释这种反常现象。喀喇昆仑山脉西部的天气模式转移和降雪/积雪（MODIS 数据分析）的增加等趋势，并不能提供冰川退化的直接证据。本文在全球气候模式的三种排放情景（IPCC 第五次报告的 RCP2.6，RCP4.5 和 RCP8.5 情景）下预测了未来的径流量。预测结果表明，河流径流在本世纪中叶之前增加，之后会下降，这就为喀喇昆仑山的冰川趋于稳定或者增加现象提供了强有力的证据。通过高分卫星日尺度，月尺度，和年尺度的降水产品结合在喀喇昆仑，帕米尔高原和天山 地区的地面观测数据进行估算。通过 ME 值获得的最佳相关系数表明有少量的降水被低估。 同理，在年时间尺度上，降水观测数据和卫星降水产品的最大偏差，中误差，平方根误差和误差有很强的相关性。在具有 95％置信区间的测量站和CHIRPS 产品之间也观察到良好的相关性（r≥0.80）。观察到 CHIPRS 数据集的最大偏差（0.98）和中误差（-0.23mm decad-1）。在气候变化情境下，结合地面观测数据，MODIS 积雪覆盖产品和 CHIRPS 降水产品，本研究解释了巴基斯坦境内印度河上游流域积雪变迁现象。本研究还提供了罕萨河对气候变化响应的有关信息。这些结果可用于制定该区域未来可持续水管理的有效战略，同时克服下游水库如 DiamerBasha水坝的蓄洪和水存储的脆弱性。这些发现可以帮助对该地区季节性径流的预测，以及用雪盖变化来作为气候变化的响应
Flocculation and Transparent Exopolymer Particles Formation of Microbial Mat Extracellular Polymeric Substances from a Hypersaline Lake
No full textThis study investigated the mechanism of flocculation and transparent exopolymer particles (TEP) formation of extracellular polymeric substances (EPS) from mixed algal-bacterial biofilm mat from hypersaline lakes. Various spectrophotometric techniques were employed along with parallel factor (PARAFAC) modelling on the sample excitation-emission matrix (EEM) spectra. EPS with exposure to sunlight was found to form larger TEP and floc particles of variable sizes, confirmed from turbidity test, ζ−potential (−mV) and PSD (d.nm) assay in the first few hours of sunlight exposure. It further suggested that floc/TEP formation from EPS could occur by charge neutralization and bridging mechanism. Correspondingly, EEM-PARAFAC identified humic-like and protein-like or tryptophan-like components in both raw and treated EPS samples. After the fifth day of solar irradiation, humic-like substances were entirely decomposed whilst the regenerated protein-like substances from EPS were the key components remained in irradiated samples. Degradation of EPS, particularly protein molecules of EPS was observed from the result of HPLC−SEC, which was confirmed from degradation of DOC, total protein and total polysaccharide analysis. FTIR of treated EPS and filtered EPS had more –COOH, C−H, and –C–O groups indicating acidic polysaccharide typical of TEP. With increasing pH, EPS flocculated with increasing PSD (d.nm) while a decrease in PSD (d.nm) was observed with decreasing pH. Microscopic images with AB dye assay showed a significant increase in floc/TEP at pH 10 followed by pH 8.Incubation over 24 hours with different concentration of NaCl (0 mM to 60 mM) had noteworthy effect on floc/TEP formation. But AB dye assay image with NaCl treatment showed no significant differences in floc/TEP size by changing the concentration of NaCl. ATR-FTIR spectroscopy analysis confirmed C=O and C–N groups. The carboxylic and phenolic (–COO− /–O − ) containing protein molecules in EPS might be responsible for EPS-metal (Mn+)–protein or EPS- metal (Mn+)-polysaccharide complexation by higher pH and Na+/Cl−leading to TEP/flocformation.The TEP/floc formation mechanism of EPS in response to different divalent cations (Fe2+, Ca2+ and Mg2+) with different concentrations (2 mM, 0.5 mM and 10µM) were observed. In the course of time a significant charge drop was observed with increasing concentration of Fe2+ followed by a larger floc/TEP formation in the first six hours. However, the larger floc/TEP broken down into daughter particles in the next 24 hours (approximately ~1652 d.nm). Microscopic investigation of AB dye confirmed fibrillar amorphous floc/TEP formation after 24 hours of incubation EPS adjusted with FeCl2 , CaCl2 and MgCl2. PSD assay confirmed highest floc/TEP formation in FeCl2 treatment compared to CaCl2 and MgCl2 treated EPS. ζ−potential, PSD and turbidity assay confirmed that particle bridging and particle breakage were dominant. Excitation-emission (EEM) spectroscopy along with parallel factor (PARAFAC) analysis confirmed protein-like, tryptophan-like and humic-like substances of EPS formed complexes through donation of their electrons to Fe2+, Ca2+,Mg2+ and that subsequently formed TEP/floc. It is, therefore, evidence from the above experiments that EPS can transform itself into the floc/TEP in a natural environment by the influence of sunlight, pH, salinity and different types of divalent cations that alter the geochemical interaction in natural waters
极端干旱区几种典型多年生植物根际微生物群落特征研究
No full text根际作为植物-土壤-微生物复合体，在土壤生态系统中最为活跃。植物通过根系与土壤、微生物发生偕同作用，共同作用于生态系统。根际微生物能在土壤-植物之间自由穿梭，参与能量转换与物质运输，在根际微环境中占据重要地位。由于受到气候变化和人类活动等因素的影响，极度干旱区的荒漠生态系统结构极其脆弱，并出现不同程度的退化。退化生态系统修复的主要措施之一是利用多年生优势植物进行植被恢复与重建。因此，系统研究和综合评价极端干旱区多年生植物根际微生物群落特征，对于退化生态系统修复具有重要的科学意义和应用价值。本研究依托中国科学院吐鲁番沙漠植物园和策勒荒漠草地生态系统国家野外研究站，通过自然条件下实验和人工控制实验，利用划线平板法、BIOLOG法、高通量测序、土壤化学元素分析法等相结合的方法，对几种典型多年生优势植物疏叶骆驼刺（Alhagi sparsifolia Shap.）、多枝柽柳（Tamarix ramosissima Ledeb.）、头状沙拐枣（Calligonum caput-medusae Schrenk.）的根际微生物群落特征及对生态系统修复的作用进行定位研究。结果表明：（1）在根际微生物生境特征方面：在自然环境实验中，植物种、土壤深度及其交互作用对根际土壤理化性质各指标都有极显著的影响。根际土壤含水率极低，各样品土壤含水率范围在1.01%~1.12%之间。三种植物根际土壤均呈现弱碱性，pH值范围在7.76~8.37。电导率（EC）大小排序：疏叶骆驼刺>多枝柽柳>头状沙拐枣。疏叶骆驼刺根际土壤C、N、C:P、N:P显著高于多枝柽柳和头状沙拐枣；根际土壤P含量从大到小依次为多枝柽柳>疏叶骆驼刺>头状沙拐枣；根际土壤C:N均值排序为：多枝柽柳>头状沙拐枣>疏叶骆驼刺。土壤深度与根际土壤C、P、C:P、N:P存在极显著相关性。（2）在微生物数量分布方面：研究发现细菌占根际可培养微生物数量中的多大多数。每种植物根际细菌数量、微生物总数在不同土层有相同的波动变化规律。根际真菌、放线菌在不同植物不同土层也呈现差异性分布。根际细菌数量、微生物总数排序为：头状沙拐枣>疏叶骆驼刺>多枝柽柳。根际真菌、放线菌数量排序为：疏叶骆驼刺>多枝柽柳>头状沙拐枣。除多枝柽柳、头状沙拐枣根际细菌、放线菌、微生物总数在0-50 cm和200-250 cm土层呈现负效应，其余样本根际效应均为正效应。（3）在微生物群落结构多样性方面：从所有样品中共获得根际细菌36门、77纲、105目、270科、1133属，获得根际真菌8门、727纲、87目、17科、439属，其中包含很多新的菌属。三种植物在较浅土层优势细菌菌门为放线菌门（Actinobacteria），随土壤深度的增加变形菌门（Proteobacteria）逐渐替代放线菌门（Actinobacteria）成为优势菌门。疏叶骆驼刺根际土壤优势细菌属为Pseudosphingobacterium，多枝柽柳和头状沙拐枣根际土壤优势细菌属均为拟无枝酸菌属（Amycolatopsis）。三种植物根际真菌优势菌门都是子囊菌门（Ascomycota）。疏叶骆驼刺根际真菌优势菌属是赤壳属（Nectria），多枝柽柳为桦褐孔菌属（Inonotus），头状沙拐枣为粉孢革菌属（Coniophora）。（4）在微生物功能多样性方面：根际微生物群落代谢平均颜色变化（AWCD值）排序为：疏叶骆驼刺>多枝柽柳>头状沙拐枣。其中疏叶骆驼刺根际微生物AWCD最高土层为100-150 cm，多枝柽柳为0-50 cm，头状沙拐枣为200-250 cm。AWCD值最高的土层，多样性指数H和多样性指数U值也最大。主成分分析共提取了8个主成分构成根际微生物功能代谢主要碳源，其中包含氨基酸4种、单糖3种、胺类2种、酸类2种、醇类1种共计12种碳源，主要碳源利用类型是氨基酸和单糖。（5）微生物数量与群落功能多样性对植被修复的响应：利用头状沙拐枣植被修复后土壤中细菌、放线菌数量、微生物总数比其他疏叶骆驼刺和多枝柽柳植被修复后多，利用疏叶骆驼刺植被修复后土壤中真菌数量最多。疏叶骆驼刺植被修复后土壤微生物代谢活性（AWCD值）最强，多枝柽柳植被修复后土壤微生物功能多样性最高。疏叶骆驼刺和多枝柽柳植被修复后中间土层微生物数量较多，头状沙拐枣植被修复后较深土层微生物数量较多。疏叶骆驼刺、头状沙拐枣植被修复后较深土层微生物代谢最强，多枝柽柳植被修复后中间土层微生物代谢最强。植被修复后荒漠土壤主要碳源利用类型是酸类与氨基酸类
含氮消毒副产物生成势及消毒副产物毒性
No full text饮用水消毒副产物(DBPs)是近 40 年来饮用水安全的研究热点之一。虽然在饮用水消毒过程中含氮消毒副产物(N-DBPs)生成势低于含碳消毒副产物(C-DBPs)，但因其具有较高的细胞毒性及基因毒性而被广泛研究。本论文通过野外采样分析与实验室化合物模拟分析相结合，研究了不同水源水 N-DBPs 生成势特征、水质及氯化条件对DBPs 生成势的影响、消毒副产物对小鼠的生理毒性和生殖毒性。初步得出如下结果：1. 新疆和广东两地水源水的氯化和氯胺化结果说明氯胺消毒可降低 N-DBPs 的生成势；从地域而言，新疆地区水源水 HNMs 生成势高于广东地区，广东水源 HANs生成势高于新疆水源，N-DBPs 生成势为广东水源高于新疆水源，原因是广东地区人类活动和水生生物代谢活动高于新疆地区；从季节而言，夏季新疆水源水 HNMs、HANs、N-DBPs 的生成势均高于冬季，这与气温影响水生生物生命活动有关。2. 在氯化糖类和酚类过程中，得出亚硝酸氮是氯化酚类形成 TCNM 的氮源，而并非氯化糖类形成 TCNM 的氮源。TCNM 的生成量受苯环上所连接官能团种类、数量及位置的影响。邻苯二酚、间苯二酚和间苯三酚的正交实验结果表明，pH 是影响TCNM 形成的关键因子，反应时间和反应温度影响较微弱。3. 在氯化消毒邻苯二酚与亚硝酸根过程中，首次发现了金属离子对 TCNM 形成具有明显的增强效果，促进作用顺序为 Fe3+＞Ti4+＞Al3+，且促进强度与金属离子浓度呈正比例相关。氯化条件的影响：金属离子对 TCNM 形成的促进作用在弱碱性条件(pH 8-9)高于弱酸性和中性；无论是延长反应时间还是提高反应温度，都未明显影响金属离子对 TCNM 形成的促进效果。此外，多种金属的共同作用效果与其中具有最高促进作用的金属离子相接近。4. 在氯化消毒色氨酸过程中，随着投氯量由 10 mg/L 增加到 75 mg/L，HAAs、HKs 生成势随之升高，HANs 生成势先降低再升高后降低，HNMs 生成势先升高后降低，对 THMs 生成势无影响，最佳适宜投氯量为 50 mg/L，DBPs 的生成势为 HAAs＞THMs＞HNMs＞HANs＞HKs。pH 升高会提高 HANs、HKs、HNMs 生成势，降低HAAs 生成势，对 THMs 生成势影响不明显。在有余氯存在情况下，亚硝酸氮添加会促使 HNMs 生成势增加，对 THMs、HAAs、HANs、HKs 生成势影响不明显。亚硝酸氮要成为 N-DBPs 的氮源，需要满足两个条件：一是水体具有较高的芳香性，二是亚硝酸氮是水体的主要氮源。随着溴离子浓度增加，THMs、HAAs、HNMs 生成势随之增加，HANs 和 HKs 的生成势无明显变化规律；溴代消毒副产物呈正比例增加，但氯代消毒副产物并未呈正比例下降。5. 色氨酸氯化消毒溶液会抑制小鼠的发育，pH=9 消毒溶液对小鼠血液代谢影响最大且对肝脏发育抑制最强。在 pH 和 Br-的影响下，色氨酸和色氨酸消毒溶液都对小鼠的肝脏细胞造成了氧化损伤且色氨酸溶液的损伤程度高于其消毒溶液，氯化处理可降低色氨酸溴离子添加组对肝脏的氧化损伤。色氨酸消毒溶液会对小鼠的肾脏细胞造成损伤，pH=9 消毒溶液对肾脏的氧化损伤高于其它处理组，氯化处理可增强色氨酸溴离子添加组对肾脏的损伤。pH=9 消毒溶液对小鼠具有较高的生理毒性。受检 28种 DBPs 引起的肝脏和肾脏损伤并不显著。6. 在 pH 和 Br-的影响下，色氨酸溶液和色氨酸消毒溶液会影响小鼠的发育，色氨酸溶液对小鼠整体和睾丸发育的抑制作用强于其消毒溶液，氯化处理降低了溴离子添加组对小鼠发育的抑制。pH=7 色氨酸消毒溶液对小鼠睾丸组织的损伤高于其它处理组，pH 降低和溴离子添加可显著降低消毒溶液对睾丸组织的损伤。色氨酸消毒溶液对精母细胞和睾丸骨架细胞损伤高于色氨酸溶液，特别是 pH=9、pH=7 和 Br-=5mg/L 消毒溶液。pH=7 消毒溶液会抑制小鼠精子的活力，弱酸性和弱碱性消毒溶液均不利小鼠精子生成，pH=5 和 pH=7 的消毒溶液会增加精子的畸形率，pH 升高和溴离子添加会降低消毒溶液对小鼠精子的损害。在 pH 和 Br-的影响下，色氨酸溶液和其消毒溶液对小鼠具有轻微的生殖毒性，色氨酸消毒溶液对小鼠生殖毒性强于色氨酸溶液。目前的结果并不能说明色氨酸消毒溶液的生殖毒性是由受检的 28 种 DBPs 引起的