保安湖沉水植被恢复及其渔业效益   总被引：11，自引：2，他引：9  

金刚  李钟杰  刘伙泉  温周瑞  陈洪达 《湖泊科学》1999,11(3):260-266

通过消除对沉水植物生长有破坏作用的草食性鱼类和杂食性鱼类,在低水位的早春选择无风浪的天气移栽水草,于１９９年保安湖一个面积为３．３ｈｍ＾２网栏湖汊成功地恢复了绝迹８个月的水草群落,秋季水草覆盖盖达５０％,同时研究了在无鱼类摄食破坏的条件下苦草和黄丝草的生长动态。  相似文献   

Changes in overland flow and infiltration after a rangeland fire in a Mediterranean scrubland     

A. Cerd 《水文研究》1998,12(7):1031-1042

Changes in overland flow and infiltration after a wildfire (summer 1989) in a typical Mediterranean scrubland were measured during the winters of 1990, 1991, 1992 and 1995 by means of simulated rainfall. Infiltration increases gradually from 1990 (sixth months after the forest fire) to 1995 (five and a half years after the forest fire). Overland flow decreases from 45% of rainfall after the forest fire to less than 6% five and a half years later. The reduction in overland flow was greatest in the first two years after the fire because of the quick recovery of vegetation. The steady-state infiltration capacity increased every year after the fire. Runoff and infiltration changes are mainly determined by the gradual recovery of vegetation. © 1998 John Wiley & Sons, Ltd.  相似文献   

Analysis on variation characteristics of geothermal response in Liaoning Province          下载免费PDF全文

ZHU Wei  TANG Wen  LIU Qiang  ZHANG Mei-gui 《地下水科学与工程》2017,5(4):336-342

Due to energy shortage and increasing environmental awareness, resources in shallow underground space have been rapidly exploited and utilized. So that studying variation characteristics of geothermal response in gneiss is necessary for effective and rational use of underground heat. Based on field test of thermal response in gneiss under hydrogeological survey project carried out in shallow geothermal energy development zone in Liaoning Province, this thesis analyzes mathematical statistics of geothermal response characteristics in main gneiss of Laoning Province. The initial formation temperature ranges from 10.80℃ to 15.80℃ according to field test. The statistical results show that in the condition of natural water content, the average thermal conductivity of Quaternary loose rocks comes as clay silty silty fine sand medium sand coarse sand gravelly sand. This order is consistent with thermal conductivity characteristics of gneiss obtained in the laboratory. Formation temperature recovery in different strata follows as granite medium sand clay. This order is opposite to the absolute value of temperature recovery curve slope of corresponding lithology, which shows that the stratum with higher temperature recovery rate has lower temperature recovery curve slope.  相似文献   

Phytoplankton,macrophytes and benthic diatoms in lake classification: Consistent,congruent, redundant? Lessons learnt from WFD-compliant monitoring in Poland     

《Limnologica》2016

The lake monitoring programme compliant with the Water Framework Directive has been implemented in Poland since 2007. Currently, the methods for three biological quality elements (BQEs): phytoplankton (the Phytoplankton Multimetric for Polish Lakes, PMPL), macrophytes (the Ecological State Macrophyte Index, ESMI) and phytobenthos (the Diatom Index for Lakes, IOJ) are officially applied and internationally intercalibrated. Based on the monitoring data from 256 lakes surveyed in 2010–2013 and assessed for all the three BQEs, we tested whether the assessment results obtained by the three biological methods were consistent and we searched for the causes of inconsistencies which we found. The lake classifications obtained from the PMPL and ESMI were highly consistent and the relationship between these metrics was relatively strong (R = 0.66, p < 0.001). Both metrics correlated equally strongly with water quality indicators. However, the PMPL and ESMI indicated systematic dissimilarities in the sensitivity to eutrophication between shallow and deep lakes. In shallow lakes, the alarming symptoms of macrophyte community deterioration (lower values of ESMI) occurred at lower nutrient and Chla concentrations and were accompanied by a better status of phytoplankton (higher values of PMPL) than in deep lakes that can be explained by a synergistic effect of inorganic suspended solids and algal growth on water transparency. As a consequence, the positions of phytoplankton and macrophytes as early warning indicators in the eutrophication gradient in shallow lakes were inverted compared to those in deep lakes. Compared to the PMPL and ESMI, the IOJ method gave the least stringent assessment results, with 22% of lakes failing to meet the environmental objectives. The relationships between IOJ and PMPL, and ESMI were relatively weak (R = 0.17, p = 0.008 and R = 0.17, p = 0.007, respectively). Moreover, the phytobenthos index IOJ correlated significantly more weakly with all the water quality indicators than either PMPL or ESMI did. The poor performance of the phytobenthos method in this study may suggest a limited indicator value of this BQE for lake assessment or inappropriate sampling design.  相似文献   

鲁甸地震生命线工程震害特点及应急抢修   总被引：2，自引：1，他引：1  

刘爱文  帅向华  吕红山  吴健  徐超 《震灾防御技术》2014,9(3):359-367

在现场调查的基础上,本文总结分析了鲁甸地震交通、通信和电力等三类生命线工程的震害特点及应急抢修情况。鲁甸地震是一次较典型的山区地震,地震地质灾害和强地震动共同作用是造成生命线工程破坏的主要原因。交通系统的主要震害是山体滑坡引起的道路中断,灾区属于高山峡谷地形,道路抢通困难。电力系统的小型水力发电站破坏严重,龙头山变电站的破坏直接导致其下级的2个变电站也断电。通信系统在本次地震中受的影响相对较小,恢复也较快。  相似文献   

Environmental Effect Caused by Over-exploitation of Deep Groundwater in North China     

Xiu-yan WANG  Yu-hong FEI 《地下水科学与工程》2014,2(1):12-20

Based on the formation and development analysis of the environmental geological disaster of land subsidence, earth fissures and other geological disasters in the North China, it showed these disasters caused a very serious problem in some areas of the North China, such as the deep groundwater exploitation cone, which is accumulated with great damage and loss and is hard to be controlled, therefore, great attention should be paid. It is considered that the formation of the deep groundwater cone is the root of various geological environmental problems, and the groundwater cone recovery is the key to solve other environmental problems  相似文献   

中国工矿区发展形势解析及可持续发展政策研究(英文)     

李倩  张文忠  王岱 《资源与生态学报(英文版)》2014,5(1):42-52

工矿区作为中国重要的资源能源供给基地,长期以来为全国和区域经济社会发展做出了突出贡献。但随着不可再生资源的锐减,在市场经济体制下的区域竞争中,工矿区的经济、社会、生态环境问题日益凸显。本文根据从全国各省市汇总的一手数据,甄选出128个典型工矿区,经分析发现经济发展问题重点表现为可采资源面临枯竭、产业结构失调和财政收支失衡;社会发展问题重点表现为居民生活保障缺失、公共服务水平低下和管理体制机制落后;生态环境问题重点表现为工业污染严重和地质灾害频发。针对这些问题,本文重点围绕产业结构调整、管理体制改革、民生保障服务以及生态环境整治四个方面明确了未来促进工况区改造和可持续发展的对策建议。  相似文献   

国际及中国地球科学发展态势文献计量分析   总被引：7，自引：0，他引：7  

肖仙桃  孙成权 《地球科学进展》2005,20(4):467-476

以SCI、ESI（基本科学指标数据库）、GEOREF等数据库为统计分析源,对1993—2003年国际及中国地球科学的发展现状和发展态势从文献计量学的角度进行统计分析,分析了国际地球科学论文产出的主要领域、国家、机构、科学家和期刊,对中国地球科学论文产出的主要领域进行比较分析,并通过论文产出、被引频次、篇均被引频次和国际1%顶尖论文数量对比反映中国的科学影响力。结果表明,国际环境科学和生态学研究论文增长很快,占地球科学相关主题领域论文的比例也比较大,但中国生态学研究论文无论从占国内22个学科论文产出的比例,还是从占全球该领域的比例来说都有较大差距;中国地质科学领域研究重点在地球化学、金属矿产和能源的经济地质学,但在环境地质学领域研究相对较少,而国际上环境地质学研究论文的发展已经大大高于传统的地质学论文。  相似文献   

碳酸岩与铂族元素地球化学   总被引：1，自引：1，他引：0  

黄智龙许成  刘丛强 《地质论评》2005,51(4):443-451

碳酸岩（carbonatite）被视为一种研究大陆地幔地球化学的“探针岩石”,通过对这类岩石的研究,在探讨地幔组成与演化、地幔交代作用与不均一性以及岩浆形成的动力学背景、岩浆来源及演化和有关矿产的成矿作用等方面,具有重要的理论意义和实际价值。铂族元素（Platinum—group elements,简称PGE）在研究核-幔分异、地幔组成与演化以及幔源岩石（主要为基性-超基性岩）形成的大地构造背景、岩浆起源及演化,以及探讨K／T界线与陨石撞击事件等方面具有重要意义。本文在概述国内外碳酸岩和PGE地球化学研究现状的基础上,结合地质事实和地球化学研究成果,认为碳酸岩熔体具有一定携带PGE的能力,可利用PGE地球化学来探讨碳酸岩的源区特征和岩浆形成与演化过程;同时指出,碳酸岩PGE地球化学研究过程中还存在许多悬而未决的科学问题。  相似文献   

Geochemistry and mineralogy of shallow alluvial aquifers in Daudkandi upazila in the Meghna flood plain, Bangladesh   总被引：1，自引：0，他引：1  

M. Aziz Hasan  Mattias von Br?mssen  Prosun Bhattacharya  Kazi Matin Ahmed  Arif Mohiuddin Sikder  Gunnar Jacks  Ondra Sracek 《Environmental Geology》2009,57(3):499-511

The shallow alluvial aquifers of the delta plains and flood plains of Bangladesh, comprises about 70% of total land area are mostly affected by elevated concentrations of arsenic (As) in groundwater exposing a population of more than 35 million to As toxicity. Geochemical studies of shallow alluvial aquifer in the Meghna flood plain show that the uppermost yellowish grey sediment is low in As (1.03 mg/kg) compared to the lower dark grey to black sediment (5.24 mg/kg) rich in mica and organic matter. Sequential extraction data show that solid phase As bound to poorly crystalline and amorphous metal (Fe, Mn, Al)-oxyhydroxides is dominant in the grey to dark grey sediment and reaches its maximum level (3.05 mg/kg) in the mica rich layers. Amount of As bound to sulphides and organic matter also peaks in the dark grey to black sediment. Vertical distributions of major elements determined by X-ray fluorescence (XRF) show that iron (Fe₂O₃), aluminum (Al₂O₃) and manganese (MnO) follow the general trend of distribution of As in the sediments. Concentrations of As, Mn, Fe, HCO₃ ⁻, SO₄ ²⁻ and NO₃ ⁻ in groundwater reflect the redox status of the aquifer and are consistent with solid phase geochemistry. Mineralogical analysis by X-ray diffraction (XRD) and scanning electron microscopy (SEM) fitted with energy dispersive X-ray spectrometer (EDS) revealed dominance of crystalline iron oxides and hydroxides like magnetite, hematite and goethite in the oxidised yellowish grey sediment. Amorphous Fe-oxyhydroxides identified as grain coating in the mica and organic matter rich sediment suggests weathering of biotite is playing a critical role as the source of Fe(III)-oxyhydroxides which in turn act as sink for As. Presence of authigenic pyrite in the dark grey sediment indicates active reduction in the aquifer.  相似文献