Temporal-spatial dynamics of distribution patterns of microorganism relating to biological soil crusts in the Gurbantunggut Desert

Biological soil crusts serve as an important biological factor contributing to the sand fixation. This study was conducted to investigate the temporal-spatial variability of microorganism in crusts relating to locations, soil layers of sand dunes and seasons. At moss-dominated inter-dune areas, higher soil nutrient and water concentrations were likely to maintain the microbial activities. Bacteria showed the highest capabilities of settlement and growth in inter-dunes in both spring and autumn. Soil water content reached the highest value in soil crusts in the inter-dune areas, especially in spring. Variations of quantities of actinomyces and fungi basically showed the consistent trend in different locations of sand dunes. With the deepening of soil layers, vertical distribution of quantities of each microorganism group showed different characteristics because environmental factors fluctuated in both spring and autumn. Among different microorganism groups, bacteria were predominant, actinomyces the next and fungi the least in both spring and autumn in all soil layers （0-20 cm）. The proportion of bacteria and soil water content were higher in spring than those in autumn in all soil layers （0-20 cm）. No consistent trends were found in actinomyces and fungi. The results showed that the quantities of microorganisms were significantly positive correlated with organic matter content, soil water content, total N, total P, available P, available K, pH, electrical conductivity, total salt content,catalase, urease, phosphatase and alkaline phosphatase.     

毛乌素沙地上空沙尘暴的前向轨迹及其影响范围

基于气象数据、MODIS遥感影像数据和NCEP再分析资料, 利用HYSPLIT模型模拟2000—2019年毛乌素沙地上空不同海拔高度(500, 1000和1500 m)各季节沙尘暴的前向轨迹, 并与遥感影像识别出的沙尘信息进行比较, 识别毛乌素沙地沙尘暴的影响范围。结果显示: 1) 在过去的20年中, 共有143个沙尘暴月和387个沙尘暴日, 并且 2004 年以来, 毛乌素沙地发生沙尘暴的频率逐渐降低; 2) 季节性气候条件对毛乌素沙地沙尘暴的移动路径有很大的影响, 春季沙尘暴发生频率较高, 秋季发生频率最低; 3) 受毛乌素沙地沙尘暴影响的国内地区主要包括陕西省北部、山西省北部、河北省北部和中部、山东省北部和中部、北京市、天津市、内蒙古自治区东部以及东北三省, 国外受影响的地区有朝鲜、日本北部以及俄罗斯与我国交界处, 受影响的海域有渤海、黄海北部和日本海西北部。遥感影像与HYSPLIT模型的比较提供了一种对沙尘运输、扩散和沉积过程进行验证和加深了解的有效工具, 研究结果可以为防灾减灾决策及沙源地治理提供科学的参考依据。     

不同放牧方式对半荒漠草原土壤理化性质的影响

本文以中蒙两国相邻地带小针茅半荒漠草原为研究对象，对游牧和定居放牧条件下土壤理化性质进行了研究，研究结果表明：蒙古国传统游牧区和内蒙古定居放牧区土壤含水量分别为10.06%、6.71%，两者存在显著差异（P＜0.05）；蒙古国游牧区砂粒含量明显少于定居放牧区，分别为56.27%和84.23%，两者存在显著差异（P＜0.05）；游牧区除土壤全钾外其它养分指标均高于定居区，而pH定居>游牧.     

Loess in the Tian Shan and its implications for the development of the Gurbantunggut Desert and drying of northern Xinjiang

Eolian loess is widely distributed on the various geomorphic surfaces between 700–2400 m a.s.l. on the northern slope of the Tian Shan. It is formed in a synchronous manner with dust transported from the Gurbantunggut Desert in the Junggar Basin. The thickest section of loess was found in the Shawan and Shihezi regions. Paleomagnetic and climatic proxy analyses of over 71 m of a loess-paleosol sequence on the highest terrace of the Qingshui He (River) in the Shawan show that the paleomagnetic Bruhues/Matuyama (B/M) boundary lies at the bottom of paleosol S8, at a depth of 69.5 m, and the bottom of the sequence was estimated to be ∼0.8 Ma. This implies that the extremely dry climatic conditions in the Junggar Basin and the initial Gurbantunggut Desert were present at least by 0.8 Ma. High-resolution grain size series demonstrate that this area and desert expansion experienced two dramatic periods of desert expansions that occurred at ∼0.65 Ma and 0.5 Ma, respectively; and the subsequent continuous enhancement led to the environment presently observed. This tremendous environmental effect, caused by large-scale expansion of the desert and arid region of inner Asia, might be an important driving force for the global temperature drop that occurred in the mid-Pleistocene.     

Palaeolake and palaeoenvironment between 42 and 18 kaBP in tengger desert, NW China

Comprehensive field investigations and laboratory analyses show that palaeolakes, including fresh- mesohaline water Megalake Tengger and other semi-con- nected, isolated water bodies, during late Pleistocene covered an area of more than 20000 km², which is more than half of the Tengger Desert in NW China. Stratigraphic correlation and chronological evidence indicate that before ca. 42000 aBP the area was more arid. The palaeolakes started to develop around 40000 uncal. ¹⁴C aBP but until 37000 ¹⁴C aBP their scope was limited. High water levels established from 35000 ¹⁴C aBP lasted until 22000 ¹⁴CaBP. Lake levels regressed between 22000 and 20000 ¹⁴C aBP but transgressed from 20000 to 18600 ¹⁴C aBP. Subsequently, water level declined further and the Megalake Tengger finally desiccated at around 18000 ¹⁴C aBP. Megalake Tengger possessed a fresh-mesohaline water property, implying that the regional precipitation increased significantly. During the period of Megalake Tengger, the climate was warmer-humid than present. The annual rainfall was 250 to 350 mm more than that of today and the temperature was 1.5 to 3.0℃ higher.     

新疆北山地区金矿的 X 射线荧光找矿标志

文章探讨了在新疆北山地区特殊地质环境下，采用现场Ｘ射线荧光测量找金的方法技术问题。提出适合于该区快速找金的Ｘ射线荧光找矿最佳指示元素为铁、铜、砷，铁和铜的Ｘ射线荧光异常出现在垂直于金矿（化）体走向的两侧，砷的Ｘ射线荧光在金矿（化）体上呈现异常。     

The Holocene Palaeoclimatic change in southern vicinity of Tengger Desert

Through stratigraphy and chronology studies on Hongshui River section located at the southern vicinity of Tengger Desert, and based on the analysis results of TOC, TIC, elements, stable oxygen isotope that possess a high resolution of 40–50 a, the paleaoclimatic change history during last 8 000–3 000 a has been reconstructed.     

AMT法勘查额济纳盆地与巴丹吉林沙漠接触关系

 查明额济纳盆地东部与巴丹吉林沙漠之间的接触关系,有助于分析额济纳盆地地下水水位下降、生态环境恶化的原因。通过当地地质资料和物探方法的对比分析,选择合理有效的音频大地电磁法（AMT）物探手段,在该区域进行了原始创新性的勘查工作。勘查结果认为额济纳盆地上升、巴丹吉林沙漠下降,两侧地层岩性厚度变化较大,推断额济纳盆地与巴丹吉林沙漠为张性断层接触。研究可为分析两者之间地下水转化关系和额济纳盆地地下水水位下降原因、探讨盆地与沙漠区地下水形成机制提供依据,对恢复治理额济纳盆地生态环境具有一定帮助。     

古尔班通古特沙漠南缘媒介蜱群落分析

为明确目前古尔班通古特沙漠南缘媒介蜱的流行情况和分布规律,对该地区11个生境点的考查分析。结果显示,获得的2776枚媒介蜱,隶属4属11种,初步确定了莫索湾沙漠区、克拉玛依干旱区、安集海农垦区和精河平原牧场媒介蜱的种群落组成和区域分布,并对其群落结构进行了相关分析,同时确定了在古尔班通古特沙漠区媒介蜱的优势物种为残缘璃眼蜱(Hyalomama detritum detritum)、亚洲璃眼蜱(Hyalomama asiaticum asiaticum)、亚东璃眼蜱(Hyalomama asiaticam)、盾糙璃眼蜱(Hyalomama scuperse);在农垦区和平原牧场地段内则以银盾革蜱(Dermacentor niveus)、残缘璃眼蜱、亚洲璃眼蜱、亚东璃眼蜱、盾糙璃眼蜱为优势蜱种。