黑麦草在净化富营养化水的人工湿地生态工程中的作用   总被引：6，自引：0，他引：6  

牛晓音  葛滢  常杰  关保华  徐青山 《湿地科学》2004,2(3):202-207

在人工湿地生态工程中利用黑麦草(Lolium perenne L．)净化污水，得到了较好的效果。结果表明：利用黑麦草在冬春季节的生长，可使亚热带地区人工湿地常年运行，黑麦草在3—4月份对水体就有明显的净化作用。在春夏季节，特别在5月份黑麦草可以获得较高的生物量和N、P的积累量，因而净化贡献最大。从产草量方面考虑，延长黑麦草的生长期能获得较高的生物量；从植物体所含营养物质状况和饲用价值看，增加收割次数的黑麦草N、P含量高，饲用价值高；但从黑麦草对污水中N、P的吸收和积累量方面考虑，收割次数过高则不利于黑麦草对污水的净化及N、P的累积。从上述几方面综合考虑，在黑麦草整个生长期收割次数以2．3次为宜。  相似文献   

洪湖的环境变迁与生态保护   总被引：16，自引：2，他引：16  

卢山  李世杰  王学雷 《湿地科学》2004,2(3):234-237

洪湖历史上经历了多次变迁，在同类型湖泊中表现出其生态的复杂性和多样性。通过分析洪湖从成湖以来所发生的的湖泊环境变化，阐述了人类活动对洪湖环境带来的一系列生态问题，对洪湖生态环境的恢复与优化提出对策与建议；同时，对于洪湖省级湿地自然保护区的建设和管理提出了科学的、可操作的具体措施。  相似文献   

海岸带临港工业、海运物流与全球化大生产的探讨   总被引：5，自引：0，他引：5  

田汝耕  张振克  朱大奎 《世界地理研究》2004,13(2):1-8

海岸带是世界人口密集、经济发达的地带，在全球经济一体化和全球化大生产中具有重要的地位。近半个世纪以来，海岸带临港工业迅速崛起并持续高速发展，依托海港建设、大型船舶运输发展起来的临港工业和海运物流，在跨国公司的运作下形成了现代意义上的全球化大生产。这种生产方式使资源贫乏的日本快速发展成发达国家；深圳赤湾临港工业区成为中国高效益工业的典范。本文着重讨论了海岸带经济建设中大力发展临港工业对地区、国家和全球经济的影响，指出中国21世纪应大力开发利用海岸带港湾资源、重点建设全球化大生产的大进大出的基地，建立若干个具有国际竞争力的海岸带产业中心，推动国民经济持续、快速发展。  相似文献   

MODIS数据在黄河凌汛监测中的应用   总被引：11，自引：0，他引：11  

鄢俊洁  刘良明  马浩录  许志辉 《武汉大学学报(信息科学版)》2004,29(8):679-681

对MODIS数据的特性及其在黄河凌汛监测中的应用情况进行了探讨和总结。试验结果表明 ,MODIS数据在冰雪检测方面具有很大的潜力  相似文献   

Upper Pleistocene and Holocene paleosalinity and trophic state changes in relation to sea level variation in Rocha Lagoon, southern Uruguay     

F. García-Rodríguez  D. Metzeltin  P. Sprechmann  R. Trettin  G. Stams  L.F. Beltrán-Morales 《Journal of Paleolimnology》2004,32(2):117-135

Paleolimnological data are presented on trophic development in relation to sea level variation in Rocha Lagoon, a 72 km² coastal lagoon in southern Uruguay. Using sediment cores that extended to ∼20,000 yr BP, analyses of grain size, organic matter, carbonate, total carbon, nutrients, and diatoms allowed us to infer changes in trophic state and paleosalinities, which were closely related to Holocene relative sea level variation. Higher trophic states were observed during regressive events, most probably due to increases in runoff and erosion as regressions progressed. Diatom Association Zones (DAZ) were identified in both cores. Those DAZ corresponding to transgressive events were dominated by marine/brackish taxa and relatively low organic matter and nutrient values, while those DAZ corresponding to regressive events showed increases in brackish/freshwater diatoms and both organic matter and nutrients. Although the lagoon formed after the first Holocene marine transgression, our data indicate the existence of a marine/brackish aquatic system during upper Pleistocene (i.e., before 15,000 yr BP), but by ∼20,000 yr BP, the system was still likely to be a semi-arid terrestrial system.  相似文献   

Estimation of ocean primary productivity and its spatio-temporal variation mechanism for East China Sea based on VGPM model     

LI Guosheng  GAO Ping  WANG Fang  LIANG Qiang 《地理学报》2004,14(1):32-40

According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for CaseⅠand CaseⅡwater bodies respectively. The monthly chlorophyll distribution in the East China Sea in 1998 was obtained from this improved model on calculation results of SeaBAM. The euphotic depth distribution in 1998 in the East China Sea is calculated by using remote sensing data of K490 from SeaWiFS according to the relation between the euphotic depth and the oceanic diffuse attenuation coefficient. With data of ocean chlorophyll concentration, euphotic depth, ocean surface photosynthetic available radiation (PAR), daily photoperiod and optimal rate of daily carbon fixation within a water column, the monthly and annual primary productivity spatio-temporal distributions in the East China Sea in 1998 were obtained based on VGPM model. Based on analysis of those distributions, the conclusion can be drawn that there is a clear bimodality character of primary productivity in the monthly distribution in the East China Sea. In detail, the monthly distribution of primary productivity stays the lowest level in winter and rises rapidly to the peak in spring. It gets down a little in summer, and gets up a little in autumn. The daily average of primary productivity in the whole East China Sea is 560.03 mg/m2/d, which is far higher than the average of subtropical ocean areas. The annual average of primary productivity is 236.95 g/m2/a. The research on the seasonal variety mechanism of primary productivity shows that several factors that affect the spatio-temporal distribution may include the chlorophyll concentration distribution, temperature condition, the Yangtze River diluted water variety, the euphotic depth, ocean current variety, etc. But the main influencing factors may be different in each local sea area.  相似文献   

Impact of land-cover and climate changes on runoff of the source regions of the Yellow River     

LI Daofeng  TIAN Ying  LIU Changming  HAO Fanghua 《地理学报》2004,14(3):330-338

After dividing the source regions of the Yellow River into 38 sub-basins, the paper made use of the SWAT model to simulate streamflow with validation and calibration of the observed yearly and monthly runoff data from the Tangnag hydrological station, and simulation results are satisfactory. Five land-cover scenario models and 24 sets of temperature and precipitation combinations were established to simulate annual runoff and runoff depth under different scenarios. The simulation shows that with the increasing of vegetation coverage annual runoff increases and evapotranspiration decreases in the basin. When temperature decreases by 2oC and precipitation increases by 20%, catchment runoff will increase by 39.69%, which is the largest situation among all scenarios.  相似文献   

Noah's Flood: The New Scientific Discoveries About the Event that Changed History     

《The Professional geographer》2004,56(3):445-447

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Origin of the Palau and Yap trench-arc systems     

Kazuo Kobayashi 《Geophysical Journal International》2004,157(3):1303-1315

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Imaging the Dead Sea Transform with scattered seismic waves   总被引：2，自引：0，他引：2  

N. Maercklin  C. Haberland  T. Ryberg  M. Weber  Y. Bartov  the DESERT Group 《Geophysical Journal International》2004,158(1):179-186

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