沼泽湿地生态储水量及生态需水量计算方法     

李丽娟  李九一  粱丽乔  柳玉梅 《地理学报(英文版)》2009,19(4):427-436

As one of the most typical wetlands, marsh plays an important role in hydrological and economic aspects, especially in keeping biological diversity. In this study, the definition and connotation of the ecological water storage of marsh is discussed for the first time, and its distinction and relationship with ecological water requirement are also analyzed. Furthermore, the gist and method of calculating ecological water storage and ecological water requirement have been provided, and Momoge wetland has been given as an example of calculation of the two variables. Ecological water use of marsh can be ascertained according to ecological water storage and ecological water requirement. For reasonably spatial and temporal varia-tion of water storage and rational water resources planning, the suitable quantity of water supply to marsh can be calculated according to the hydrological conditions, ecological de-mand and actual water resources.  相似文献   

Assessment of nitrogen maintenance requirement in juvenile Black Porgy <Emphasis Type="Italic">Acanthopagrus schlegeli</Emphasis>     

朱秋华  钱国英  高有领  汪财生 《中国海洋湖沼学报》2009,27(1):63-68

Nitrogen balance method and nitrogen-free diet were used in this study to determine nitrogen maintenance requirement (NM) and nitrogen maintenance requirement per unit metabolism body weight (NM′) of black porgy Acanthopagrus schlegeli. Fish with body weight (BW) of 50, 80, 120, 160 and 200 g were fed by the diets containing three graded levels of crude protein (380, 420 and 460 g/kg). The results from nitrogen balance experiment showed that the amount of nitrogen deposition varied from 0.15 to 0.31 mg/g BW per day, accounting for 12.2% to 21.1% of nitrogen intake. The amount of fecal nitrogen excretion varied from 0.21 to 0.32 mg/g BW per day, accounting for 16.3% to 21.6% of nitrogen intake. The endogenous nitrogen excretion, a main part of nitrogen consumption varied from 0.79 to 0.97 mg/g BW per day, accounting for 63.3 % to 68.0% of nitrogen intake. Positive correlation was found between NM and body weight, while a negative correlation was found between NM of unit body weight and the growth duration. No significant differences (p>0.05) were found in NM′ among different growth stages. The average of NM′ was 0.485 7mg/g per day. The results from nitrogen-free diet experiment showed that a negative correlation between NM and feed intake of nitrogen-free diet. NM increased with the decrease of feed intake of fish. The average of NM was 0.482 9 mg/g BW per day that was close to 0.483 8 mg/g BW obtained from fish with 120 g BW in nitrogen balance experiment. The nitrogen balance method is recommended to be a better method for determining NM in consideration of fish stress and result stability. This study also provides a calculated result of the protein content in diets, which is necessary for maintaining fish body protein at different growth stages. The calculation was based on the amount of nitrogen required for maintaining body protein per kg BW. Supported by Scientific Research Project Grant (No.2004C100059) from the city government of Ningbo, China.  相似文献   

Capacity and economic efficiency in small-scale fisheries: Evidence from the Mediterranean Sea   总被引：4，自引：0，他引：4  

Lorenzo Idda  Fabio A. Madau  Pietro Pulina   《Marine Policy》2009,33(5):860-867

To design an effective capacity management plan for small-scale fisheries one must understand what one is measuring and define its capacity. As recognized by some authors, overcapacity is a problem that generally affects small-scale fisheries just as much as it does other types of fishing. This study aims to estimate fishing capacity, technical efficiency, scale efficiency and capacity utilization in a particular small-scale fishery in the Mediterranean, i.e., the Northwest Sardinian fleet in Italy. A non-parametric approach using a data envelopment analysis (DEA) model was applied to a sample of trawls in order to estimate their economic capacity, and related measurements were taken. The capacity and efficiency with reference to two different alternative scenarios were also calculated.  相似文献   

张掖城市湿地保护区生态需水量分析与计算          下载免费PDF全文

巴建文  马小全  秦晓燕 《甘肃地质》2009,(3):67-71

浅埋的地下水位以及泉水溢出是张掖城市湿地形成的主要原因。在充分考虑保持湿地现状的同时,顾及到湿地区内农耕区不至于因地下水位变化而产生负茴环境地质影响。将2005年8月份湿地保护区水位埋深,确定为保持湿地现状的地下水位埋深临界值。按照张掖城市湿地保护区的基本特征、表现、生态保护目标,生态需水量主要包括湿地植被蒸腾量、湿地土壤蒸发量、灌溉需水量以及景观建设需水量等。计算得生态需水量为3053．87×10^4m^3/a。湿地生态需水量的分析与计算对于制定合理的湿地保护措施具有重要意义。  相似文献   

2021—2050年河南省夏玉米净灌溉需水量对气候变化的响应     

闫旖君  徐建新  肖恒 《气候变化研究进展》2017,13(2):138-148

基于河南省17个气象站点观测资料和25个CMIP5模式预估数据,采用BCC/RCG-WG 3.0天气发生器构建区域气候变化情景,集合评估了RCP4.5情景下2021—2050年夏玉米净灌溉需水量较1961—2000年的变化及其空间分布。结果表明：全生育期内气温升高1.8℃,降水增加3.6%,引起作物需水量和有效降水量分别增加5.1%和1.5%,净灌溉需水量增加5.6%。受气温升高和降水减少的双重影响,播种－拔节期净灌溉需水量增幅较大,达到21.3%;拔节－乳熟期尽管有效降水量增加3.0%,但这并不足以抵消气温升高引起的作物需水量增加5.1%的影响,净灌溉需水量仍然增加3.4%;乳熟－成熟期,由于有效降水量增加8.2%,超过了作物需水量增加7.4%的影响,净灌溉需水量减少1.4%。豫西三门峡、孟津和豫西南栾川、西峡等4站在各生育期内净灌溉需水量均有不同程度的增加。  相似文献   

浙江余杭湿地生态修复现状及技术措施     

沈士华  朱弘  董铸梁  陈日泉  叶欢欢 《湿地科学与管理》2012,8(3):46-47

近年来,湿地生态修复的理念逐渐被人们认知和认同,一些符合生态修复理念的民生工程在各地政府的大力扶持下起到了良好的宣传与示范作用,并逐步得到推广应用。然而由于我国对湿地生态修复的研究起步较晚,湿地生态修复的理念及技术尚停留在初级阶段。根据浙江省余杭区湿地资源调查资料,分析了当前湿地修复中存在的不足,提出一些切实可行的生态修复理念及技术措施。  相似文献   

基础地理信息数据产品"检测软件"的功能需求分析     

周一 《现代测绘》2003,26(3):11-13

随着测绘全面进入数字时代,基础地理信息数据产品的质量控制已成为地理信息产业链中的瓶颈。本文针对“4D”数据产品计算机检测软件的功能需求进行了系统而全面的阐述与分析。  相似文献   

黄河下游输沙水量研究综述   总被引：13，自引：2，他引：11       下载免费PDF全文

石伟  王光谦 《水科学进展》2003,14(1):118-123

对输沙水量的计算方法,黄河下游汛期、非汛期输沙水量的研究现状,水库对输沙水量的影响,输沙用水总量的研究现状等方面分别作了回顾。分析指出,输沙水量与来水含沙量、来水流量、河道冲淤、河床前期条件等有关。黄河下游各时期输沙水量不同,汛期最小,其余依次为非汛期、冬三月、凌汛期。水库调水调沙的同时也改变着黄河下游的输沙水量。利用水库群调水调沙,使小浪底水库以造床流量、高含沙水流输沙,是目前推荐的黄河下游节水减淤高效输沙入海的主要方式。提出了一些有待进一步研究的问题。  相似文献   

湿地缺水问题的研究展望   总被引：2，自引：0，他引：2  

王芳 《湿地科学与管理》2006,2(1):12-17

湿地是水循环的主体环节,从河流、湖泊、沼泽到河口以至近岸海区,都直接受水资源开发利用的影响。由于水资源传统的开发方式和过度利用,使湿地面临严重的缺水形势。为了保护湿地,维护流域水循环,我国已经开展了湿地生态需水研究,并取得一些成果。但是,如何保障湿地需水仍是摆在我们面前的重要课题。水权是水资源管理更加科学的分配制度,因此借助水权来探索生态需水的保障机制,使湿地生态需水得到可靠保证。  相似文献   

生态环境需水研究进展   总被引：16，自引：0，他引：16       下载免费PDF全文

赵西宁  吴普特  王万忠  冯浩 《水科学进展》2005,16(4):617-622

生态环境需水研究是近年来国内外广泛关注的热点。回顾了国内外生态环境需水研究的总体情况,对生态环境需水的概念及其内涵、生态环境需水量化方法等方面的最新研究进行了全面的分析和总结,提出目前生态环境需水研究中亟待解决的一些问题和展望了生态环境需水研究的发展趋势。  相似文献