采煤塌陷对地表植物群落特征的影响

为了研究采煤塌陷对地表植被组成及其多样性的影响,对陕西省神府-东胜补连塔煤矿采煤塌陷区不同塌陷年限(2、7、12、17 a)区域和未塌陷区域(对照)植被进行抽样调查与分析. 结果表明:该区域共有14科39属46种植物,主要为草本植物;采煤塌陷对植被种类组成、物种分布有很大影响,导致植物种类显著减少31.03%~44.83%. 塌陷区优势种较对照区有较大变化,优势种由多年生草本植物演变为一二年生草本植物;但是不同塌陷年限区域植物优势种基本稳定,主要为看麦娘(Alopecurus aequalis)、烛台虫实(Corispermum candelabrum)、刺叶藜(Chenopodium aristatum)等. 采煤塌陷导致植株密度显著下降58.62%~68.00%、物种丰富度显著下降17.43%~27.00%、Margalef丰富度指数显著降低4.07%~22.76%,但植被盖度差异不显著. 采煤塌陷显著影响植物群落多样性,其中,塌陷12和17 a样地植被Margalef丰富度指数和Shannon-Wiener多样性指数较塌陷2 a样地显著提高. 群落排序结果表明,物种分布与塌陷有明显相关性. 塌陷区植株密度及其植被组成中多年生草本种数很难恢复到对照区水平,植被恢复进程十分缓慢.      

国内外采矿废弃地生态恢复研究进展

采矿废弃地的生态恢复是目前恢复生态学的一个研究热点.对于采矿废弃地进行生态恢复有着十分重要的理论和现实意义.本文对国内外的采矿废弃地的生态恢复历史与现状作了一个较为系统地回顾与总结,同时还运用恢复生态学理论,分析了采矿废弃地的类型和特点,总结了目前采矿废弃地生态恢复的主要措施和技术以及不足之处.     

神木煤矿区土壤重金属污染特征研究

通过对神府煤田开采区3个煤矿区周围土壤Cu、Cd、Cr、Mn、Ni质量分数进行测定及分析,评价了煤田开采对周围土壤的污染程度。结果表明,长期的煤炭资源开发、运输等活动,已导致周围土壤受到重金属不同程度的累积性污染,土壤中Cd、Ni质量分数高于陕西省土壤背景值,且Cd污染程度较高,Ni污染程度较低,而Cu、Cr、Mn基本不受污染。3个煤矿表层土壤各重金属元素质量分数均表现出污染区大于对照区,但这种变化幅度存在一定差异;Cu、Cr、Mn 3种重金属元素虽没有超出背景值,但已表现出一定程度的累积;煤矿周围土壤重金属污染受到开采年限、土壤质地、风向等因素的影响。3个煤矿污染区土壤剖面样品中,5种重金属元素质量分数基本上随着土壤深度的增加呈现降低的趋势,且这种趋势具有波动性。     

矿区土地复垦与对策

较系统地总结了从开矿到复垦过程中需要在土地整理方面做的工作，研究借鉴目前国内外土地复垦的方法，讨论土地复垦过程中出现的问题及复垦后所应采取的对策。     

北太平洋地区春季粉尘的空间分布特征——观测及模拟

通过对2001年4月的一次中亚强沙尘暴过程的观测事实分析和数值模拟,结果表明,源自中亚的强沙尘暴扬起的粉尘,通过西风急流远程传输到韩国、日本、北太平洋、北美大陆.北太平洋地区的沙尘沉积通量空间分布将主要取决于3个方面:沙尘沉积通量随传输距离的增加呈指数衰减;传输路径上粉尘有较高的沉降通量;沙尘过境时的降水空间格局将在很大程度上决定粉尘的沉降空间格局.     

EFFECTS OF PLACER MINING DISCHARGE ON HEALTH AND FOOD OF ARCTIC GRAYLING1

ABSTRACT: During the summers of 1982, 1983, and 1985, we assessed the effects of placer mining sedimentation on Arctic grayling, Thymallus arcticus, in the headwaters of Birch Creek, northeast of Fairbanks, Alaska. We compared differences between two streams (one that was undisturbed and one with mining activity upstream) near the confluence. Studies of caged fish demonstrated that, if grayling could not escape from streams carrying mining sediments, they would either die at high rates (sac fry) or suffer gill damage, starvation, and slowed maturation (age-O fingerlings and age-2 juveniles). Indirect effects of sedimentation, through loss of summer habitat for feeding and reproduction, may more severely affect grayling populations than the direct effects of sedimentation on the health and survival of individual fish.     

Land-cover change in upper Barataria Basin estuary,Louisiana, 1972-1992: increases in Wetland area

The Barataria Basin, Louisiana, USA, is an extensive wetland and coastal estuary system of great economic and intrinsic value. Although high rates of wetland loss along the coastal margin of the Barataria Basin have been well documented, little information exists on whether freshwater wetlands in the upper basin have changed. Our objectives were to quantify land-cover change in the upper basin over 20 years from 1972–1992 and to determine land-cover transition rates among land-cover types. Using 80-m resolution Landsat MSS data from the North American Landscape Characterization (NALC) data archive, we classified images from three time steps (1972, 1985, 1992) into six land-cover types: agriculture, urban, bottomland hardwood forest, swamp forest, freshwater marsh, and open water. Significant changes in land cover occurred within the upper Barataria Basin over the study period. Urban land increased from 8% to 17% of the total upper basin area, primarily due to conversions from agricultural land, and to a lesser degree, bottomland forest. Swamp forest increased from 30% to 41%, associated with conversions from bottomland hardwood forest and freshwater marsh. Overall, bottomland forest decreased 38% and total wetland area increased 21%. Within the upper Barataria, increases in total wetland area may be due to land subsidence. Based on our results, if present trends in the reduction of bottomland forest land cover were to continue, the upper Barataria Basin may have no bottomland hardwood forests left by the year 2025, as it is subjected to multiple stressors both in the higher elevations (from urbanization) and lower elevations (most likely from land subsidence). These results suggest that changes in the upper freshwater portions of coastal estuaries can be large and quite different from patterns observed in the more saline coastal margins.     

Chemical Changes in Sediment Pore-Waters of an Acidic Mining Lake After Addition of Organic Substrate and Lime for Stimulating Lake Remediation

In the past five years, enclosures have beeninstalled in an acidic mining lake in Lusatia to investigate insitu remediation processes. They were treated with straw, withstraw and Carbokalk, or with Carbokalk alone, where Carbokalkis a by-product of the sugar industry (solid precipitate ofnon-sugars after lime clarification of extracted sugar beetjuice). Sediment samples were taken as cores to get informationabout the behaviour of organic and inorganic components insediment pore-water with depth. Vertical distributions of pH,soluble reactive phosphate, nitrate, ammonium, silica,aluminium, iron, manganese, calcium, magnesium, sodium,potassium, sulphate, and DOC were measured. The resultingprofiles, each consisting of 15 data points at differentdepths, were compared by cluster analysis. The similarities ofsediment cores from different treated enclosures relating toprofiles of chemical components were discussed. Increasedconcentrations of potassium and sulphate were found in pore-water after substrate treatment. The data imply dissolution ofpotassium iron sulphate hydroxide minerals (jarosite) after anincrease of pH caused by dissolution of lime and by sulphatereducing processes which were stimulated by organic substrateaddition.     

煤层底板采动导水破坏深度计算的神经网络方法

在综合分析影响煤层底板采动导水破坏深度因素的基础上 ,应用人工神经网络方法 ,建立了底板破坏深度的计算模型。该模型利用现场观测资料作为学习训练样本和测试样本 ,对模型的测算结果、理论计算值和实测值进行了对比分析。结果表明 :用神经网络方法计算底板破坏深度考虑的因素更加全面 ,结果更接近于实际。笔者研究的计算模型和测算方法 ,为承压水上安全采煤决策提供了科学依据。     

Locational Probability for a Dammed, Urbanizing Stream: Salt River, Arizona, USA

/ Data from historical aerial photographs analyzed with a GIS show that river channel change on the Salt River in the Phoenix metropolitan area of central Arizona has been driven by large-scale regional flood events and local human activities. Mapping of functional surfaces such as low-flow channels, high-flow channels, islands, bars attached to channel banks, and engineered surfaces shows that during the period from 1935 to 1997, the relative areal coverage of these surfaces has changed. Flood events have caused general changes in sinuosity of the low-flow channel, but islands have remained remarkably consistent in location and size, while channel-side bars have waxed and waned. The most important determinant of local channel form and process is sand and gravel mining, which in some reaches occupies more than 70% of the active channel area. The general location of mining is closely related to the location of the moving urban fringe, which serves as a market for sand and gravel during construction. Quantitative spatial analysis of imagery supplemented by field mapping shows that for each location within the general channel area, it is possible to specify a probability of encountering a low-flow channel or other fluvial features. Maps showing the distribution of these probabilities of occurrence reveal the most probable location and configuration of the channel as it occurred in the past. Some reaches have the low-flow channel located persistently within a limited area as a result of bedrock or sinuosity controls, but other reaches dominated by flow separation or shallow gradient have almost no persistence in channel location from one flood to another.