新疆鄯善产淀粉酶沙漠放线菌的生长特性研究

通过对从新疆鄯善特殊沙漠环境采集的沙样中分离纯化获得89株沙漠放线菌菌株进行分析研究,筛选出淀粉酶活力高的四株放线菌,继而进行了NaCl耐盐实验,pH耐受实验,温度耐受实验研究。生长特性研究结果表明,沙漠放线菌对NaCl浓度具有广泛的适应性,属于中等嗜盐菌,最适生长酸碱度和温度数值范围分别为7~9℃和28~48℃。XSS040804菌株的最高耐受温度为55℃。     

Validating a dust production model by field experiment in Mu Us Desert, China

It is essential for validation and improvement of a dust production model to perform field observations on dust emissions. The dust production model (DPM model) consists of two physically explicit sub-models, namely saltation model [1, 2] (eq. (1)) and sandblasting model [3] (eqs. (2) and (3)). Fh is saltation flux, E is fraction of erodible surface, C is a dimensional constant, ρa is air density, g is gravitational acceleration, U* is the wind friction velocity, Ut*(Dp) is threshold frict…     

干旱区内陆河流域荒漠河岸林变化研究

新疆塔里木河流域以胡杨为建群种的荒漠河岸林是我国及世界上胡杨分布最为集中的地区之一。通过分析该地区土壤含水率、地下水埋深、地形地貌类型与胡杨空间分布、龄级结构、郁闭度的关系,探讨其生长状况。同时,采用１９８３年、１９９２年及１９９６年遥感信息源编制植被专题图件,在ＧＩＳ支持下处理图件,并应用制图数据及相关自然及人文数据,分析胡杨面积变化及演替规律,强调了系统重建设及恢复的重要作用。     

天漠嗜盐和耐盐细菌产淀粉酶活性及菌株多样性

采用平板水解圈法对分离自张家口天漠沙土的嗜盐和耐盐细菌（含放线菌）进行淀粉酶活性筛选,运用基于16S rRNA基因序列的分析方法对活菌株进行系统发育多样性分析.结果表明,76个受试菌株中,有34株淀粉水解酶活性呈阳性（44.7%）,其中有6株具有较强的淀粉水解酶活性;系统发育分析显示34个阳性菌株类群多样性和物种多样性较高,可以归为18个物种,分属于细菌域（Bacteria）的2门（Actinobacteria,Firmicutes）2科（Streptomycetaceae,Bacillaceae）8属（Streptomyces,Bacillus,Gracilibacillus,Halobacillus,Oceanobacillus,Piscibacillus,Thalassobacillus,Virgibacillus）;产淀粉酶活性较强的6株菌均属于厚壁菌门（Firmicutes）芽孢杆菌科（Bacillaceae）,分属于该科的3个属.其中菌株JSM 1684012,JSM 1684041和JSM 1685098属于芽孢杆菌属（Bacillus）;JSM 1684067和JSM 1685082属于纤长芽孢杆菌属（Gracilibacillus）;JSM 1685081属于喜盐芽孢杆菌属（Halobacillus）.以上结果说明分离自张家口天漠沙土的嗜盐和耐盐菌中存在较高比例的产淀粉酶菌株,且这些菌株具有较高的类群多样性和物种多样性.     

基于MODIS数据的巴丹吉林沙漠冬季暖岛空间分布特征及其研究

使用遥感与地理信息系统技术,利用2012年12月-2013年2月的MODIS地表温度数据产品对巴丹吉林沙漠地区冬季地表温度进行研究.将巴丹吉林沙漠分为湖泊区、沙漠外围区和沙漠周边区3个区域,旨在对3个区域的白天和夜晚地表温度进行研究对比.结果显示位于巴丹吉林沙漠腹地的湖泊区冬季白天和夜晚平均地表温度为6.10?C和-14.37?C,沙漠外围区分别为4.25?C和-15.44?C,沙漠周边区分别为4.07?C和-14.29?C,存在沙漠腹地湖泊区地表温度明显高于沙漠其他区域的"暖岛效应",其形成机制可能与远程地下水补给湖泊群有关.     

沙漠砂混凝土轴心受压应力-应变曲线试验分析

为探究单一变量下沙漠砂混凝土应力-应变全曲线,分别设计4组不同沙漠砂取代率的棱柱体混凝土试块,进行单轴受压试验,分析沙漠砂混凝土破坏现象、破坏过程以及破坏特征,并研究不同沙漠砂取代率对沙漠砂混凝土峰值应变、极限应变、弹性模量的影响.研究结果显示:沙漠砂混凝土与普通混凝土相比,其破坏特征具有一定的差异性;取代率为20％时沙漠砂混凝土其轴心受压强度达到最高,且胶凝材料对沙漠砂包裹效果较为明显;沙漠砂混凝土脆性明显高于普通混凝土;沙漠砂混凝土无量纲应力-应变曲线上升段、下升段均采用过镇海模型较为贴合,且能准确描述沙漠砂混凝土在单轴受压作用下的变形特征.     

New eco-morphological-behavioural approach of the chinchilla rats in the pre-Andean foothills of the Monte Desert (Argentina)

This study characterizes the ecology, behaviour and morphology of populations of Abrocoma schistacea and A. uspallata in north-western Argentina. We carried out live-trapping, tagging and recapture during 2006–2008. Burrow structure and vegetation were described. Diet composition and the activity of chinchilla rats were defined. Both species inhabit rock crevices in the pre-Andean foothills of the Monte Desert. Some of their morphological specializations for saxicolous life, such as foot pads for better traction on rocky surfaces and reduced nails, are convergent with those of other saxicolous species. Both species appear to be diurnal, with activity peaking in the early morning. Dietary analyses suggest trophic specialization by both species. Density of A. schistacea was of 0.15 ± 0.06 individuals ha^?1; with individuals living in groups of 3–4 animals. Given their low abundance, restricted distribution and high level of habitat and food specialization, we urge that populations of this species be protected through effective management.     

浅析塔克拉玛干沙漠降水云系特征及演变规律

文章在分析前人研究成果的基础上,总结归纳了塔克拉玛干沙漠降水云系的基本类型、特征、环流形势和云系演变的一般规律.云系类型归纳起来可以分为四大类:冷锋涡旋云系类,南支槽盾状云系类,大槽、低涡云系类,副热带西风急流云系类.这四类云系只要进入塔里木盆地活动,都会影响塔克拉玛干沙漠降水或大风、沙尘天气.     

Distribution of sand dunes and sand shifts along the southern fringe of the Mu Us Desert since the Ming Dynasty

This article takes the two segments of the Ming Great Walls, Dabian and Erbian, and their associated barracks and forts as geographical references. Based on a detailed scrutiny of historical records of the Ming and Qing dynasties, and on field surveys, the southern boundaries of the sand dunes and sand shifts of the Mu Us Desert in the Ming and Qing dynasties are carefully reconstructed. A comparison of the southern boundaries of the sand dunes and sand shifts of the Mu Us Desert in Ming and Qing with the modern boundary revealed in remote sensing imagery clearly shows that the southern boundary of dunes and shifts in the Mu us Desert has expanded only in a few areas and on a small scale. In the area to the south of Changle Fort, along the direction of annually prevailing winds, sand drifts have penetrated through the Jialu River valley into the loess region and have formed a sand strip of 32 km long and 3 km wide. To the east of Qingping Fort, sand drifts penetrated toward the eastern loess region through the Luhe River valley and have formed another sand strip of 8 km long and 2 km wide. Generally speaking, though the intensity of human activity has been increasing in this area since the Ming Dynasty, the Mu Us Desert has not significantly expanded toward the southeast or southwest. The sand-loess boundary in the southern fringe of the Mu Us Desert has been almost unchanged since the Ming Dynasty.     

干旱荒漠草原型流域水文干旱和气象干旱关系

为了合理评估干旱对荒漠草原流域的影响程度,准确判断气象干旱与水文干旱之间的传播特征,以艾不盖河流域作为典型研究区,基于1965—2021年共57年的月降水和径流资料,计算三种不同时间尺度的SPI和SRI,分析了气象干旱和水文干旱的演变过程、趋势特征及相关性。研究结果表明：应用标准化降水指数SPI和标准化径流指数SRI能够很好地反映气象干旱和水文干旱变化状况;SPI值和SRI值对降水量和径流量的敏感性随着时间尺度的增加而降低,时间尺度越大,发生高等级气象干旱事件和水文干旱事件的频数越高;发生气象干旱事件和水文干旱事件的趋势增强,且发生水文干旱的程度和可能性较气象干旱更重;时间尺度越大,水文干旱与气象干旱相关性越好,同时水文干旱要滞后于气象干旱,滞时为0—1月。研究结果为荒漠草原流域抗旱减灾提供了有效的理论支撑。