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231.
芦苇与海三棱藨草中重金属的累积及季节变化   总被引:11,自引:2,他引:11  
通过分析上海滨岸潮滩芦苇和海三棱藨草根系、茎叶中Cu、Pb、Fe、Mn、Zn、Cr、N的含量,发现Fe、Mn、Zn、Cu在芦苇与海三棱藨草根系、茎叶中含量较高,而Pb、Cr、N含量较低;Mn在芦苇与海三棱藨草茎叶中的含量接近或超过根系中的含量,而Fe在茎叶中的百分含量较少;聚类分析表明,Pb、Cr在芦苇和海三棱藨草体内的迁移能力非常相近,Zn、Cd、Cu也表现出类似的规律;芦苇和海三棱藨草分别在夏季和春季开始大量吸收重金属元素,之后含量降低,冬季时重金属元素在这两种潮滩植物根系和茎叶中再次出现富集。在同一采样断面,除Cr以外,其余重金属元素在海三棱藨草体内的含量明显高于芦苇。  相似文献   
232.
罗源湾的潮流, 余流特征   总被引:3,自引:0,他引:3  
根据罗泊湾(包括可门水道)的实测涨流资料,分析得出罗源湾湖流、余流的水平和垂直分布特征。结果表明:(1)罗源湾为强潮流作用的港湾,可门水道冈屿附近海域潮流流速较大,而湾的南部海域潮流较弱。(2)而罗源湾潮流的垂直分布来看,潮流流速中层最大、有层次之、底层最小,但潮流流速的这一垂直分布特征一般只出现在高潮前,后2-4太阴时的时段内。(3)在高、低潮前后,湾顶(特别是西北湾顶)以及可门水道附近海域上、  相似文献   
233.
Marsh creation is currently receiving wide attention in the United States as an important tool for mitigating the impacts of development in coastal wetlands. The perception that there is no net loss in valuable coastal wetlands when development is mitigated by the creation of man-made marshes can have a substantial impact on the permitting and decision-making processes. The effective result may be the trading of natural salt marshes for man-made marshes.Techniques for marsh creation were developed by the US Army Corps of Engineers to enhance and stabilize dredge spoil materials. Most research sponsored by the Corps has been directed at determining whether these goals have been accomplished. A survey of the research indicates that there is insufficient evidence to conclude that man-made marshes function like natural salt marshes or provide the important values of natural marshes. It is necessary, therefore, for decision-makers to understand the limitations of present knowledge about man-made marshes, realistically evaluate the trade-offs involved, and relegate mitigation to its proper role in the permitting process—post facto conditions imposed on developments that clearly meet state qualifications and policies.  相似文献   
234.
ABSTRACT: This paper presents research conducted on tidal power generation utilizig atmospheric pressure or air recirculation. The proposed methods in this paper differ from conventional methods. That is, they require simple and relatively inexpensive power generating facilities that would convert the potential energy of the tides into kine tic energy of air for driving the air turbines in a power plant. The characteristics of the new methods are as follows: (1) in tidal power generation utilizing the atmospheric pressure, the air pressure exerted on an air turbine can be maintained at 1 atm regardless of the water head; (2) in tidal power generation utilizing the air recirculation, the air pressure exerted on an air turbine can be made twice as high as the available water head; (3) higher tidal energy conversion efficiency can be obtained by flowing larger quantities of water in a shorter time period; (4) the generating turbines can be located at a convenient place remote from the reservoir; and (5) equipment corrosion due to salt is minimized.  相似文献   
235.
脱硫石膏农业利用研究进展与展望   总被引:15,自引:0,他引:15  
概述火电厂脱硫石膏定义、生产过程和性质。简述了脱离石膏的工业利用,详述了脱离石膏对酸性和碱性土壤改良的现状和机理,并展望了脱硫石膏促进滩涂土植被演替的前景。  相似文献   
236.
The South Carolina Estuarine and Coastal Assessment Program (SCECAP) was initiated in 1999 to assess the condition of the state's coastal habitats using multiple measures of water quality, sediment quality, and biological condition. Sampling was subsequently expanded to include components required for the National Coastal Assessment (Coastal 2000) Program. Habitats are classified as either tidal creeks (<#60; 100 meters in width) or larger open water bodies. Approximately 30 sites are sampled within each habitat during the summer months using a probability-based random sampling design. Results obtained from the first two years of sampling documented significant differences in several water quality parameters (DO, salinity, pH, turbidity, fecal coliform bacteria, total nitrogen, TKN, total phosphorus) and biological measures (chlorophyll-a, finfish and crustacean abundance and biomass and a number of benthic species) between the tidal creek and open water habitats. These differences highlight the value of partitioning shallow water habitats separately from the larger open water bodies traditionally sampled in estuarine monitoring programs, especially since tidal creeks serve as critical nursery areas for many species. Based on the differences observed, there is a clear need to identify different physical and biological thresholds for evaluating the condition of each habitat type.  相似文献   
237.
为研究双酚A(BPA)在河口水中的光解动力学及水中重要溶解性组分对其光解的影响,在广西钦州大榄江连接茅尾海的河口水域采取水样,通过模拟日光实验研究了河口水中BPA的光解动力学,及河口水中的重要溶解性组分Cl-,Br-,溶解性有机质(DOM),NO3-和HCO3-对BPA光解的影响.结果表明,河口水中BPA的光解速率常数k值比纯水中大,且上游水样中BPA的k值是下游水样的2.5倍.稳态光解实验表明DOM及其与卤素离子作用显著影响BPA的光解,虽然NO3-也影响BPA光解,但与DOM共存时,NO3-的影响不明显.自由基淬灭和竞争反应动力学实验发现激发三重态DOM(3DOM*)和卤素自由基(HRS)是决定河口水样中BPA光降解的主要活性物种,且3DOM*与BPA的反应活性(二级反应速率常数k3DOM*,BPA=4.42×108L/(mol·s)要高于HRS与BPA的反应活性(kBPA,Cl·=2.11×108L/(mol·s),kBPA,Cl2·-=8.5×106L/(mol·s).下游水样中高含量的卤素离子(292mmol/L)易淬灭3DOM*产生反应活性较低的HRS,致使下游水体中BPA的光解速率低于上游水体.  相似文献   
238.
选取闽江口塔礁洲淡水感潮野慈姑(Sagittaria trifolia L.)湿地为研究对象,2015年12月—2016年10月,每月小潮日原位定期向实验样地施加2个沉降量水平的硫酸钾溶液:S60(60 kg·hm-2·a-1)和S120(120 kg·hm-2·a-1),运用静态箱-气相色谱法研究模拟硫酸根沉降对河口区淡水感潮湿地N2O通量的影响及主要环境影响因子.对照、S60和S120 3个处理下N2O通量分别为(58.06±23.07)、(23.50±22.85)和(20.75±7.83)μg·m-2·h-1,年尺度上,S120处理显著降低N2O通量(p0.05),S60处理与CK处理差异不显著(p0.05).闽江口淡水感潮野慈姑湿地整体上表现为大气中N2O源.野慈姑湿地N2O排放通量与间隙水盐度呈显著负相关关系.研究表明,对于亚热带河口区淡水感潮野慈姑湿地,施加量为120 kg·hm-2·a-1的模拟硫沉降显著降低其N2O排放通量.  相似文献   
239.
河口潮滩湿地CH4、CO2排放通量对氮硫负荷增强的响应   总被引:2,自引:1,他引:1  
以闽江河口区高、中潮滩短叶茳芏湿地为研究对象,于2014年6—11月植物生长季进行氮硫负荷增强实验,利用静态箱-气象色谱法测定土壤CH_4、CO_2排放通量,并同步观测相关环境因子.结果表明,氮硫负荷增强对潮滩湿地CH_4、CO_2排放通量的影响不尽一致.与对照相比,NH_4~+-N输入使高、中潮滩CH4排放通量分别提高了(107.53%,7.19%),使高潮滩CO_2排放通量增加了3.39%,中潮滩减少了3.00%;NO_3~--N输入使高潮滩CH4、CO_2排放通量分别增加了(29.99%,16.99%),使中潮滩分别减少了(3.45%,4.77%);SO_4~(2-)-S输入使高、中潮滩CH4排放通量分别减少了(8.99%,7.67%),使高潮滩CO_2排放通量减少了3.87%,中潮滩增加了5.44%;N-S复合输入使高、中潮滩CH4排放通量分别提高了(72.48%,25.66%),CO_2排放通量提高了(13.32%,13.48%).氮硫负荷增强改变了短叶茳芏沼泽生长季CH_4、CO_2排放通量变化规律,但除了NH+4-N处理对高潮滩CH4通量的影响显著外,其他处理影响均未达到显著性水平.相关分析显示,高、中潮滩湿地CH_4、CO_2排放通量与土壤温度,含水率具有显著的正线性相关关系,与土壤电导率相关性不显著.在全球环境问题日益严重背景下,系统研究湿地生态系统温室气体排放的机制与规律,对于准确估算全球温室气体排放量具有重要而直接的意义.  相似文献   
240.
ABSTRACT. The Texas Water Development Board, the principal water resource planning agency of the State, has been conducting extensive estuarine data collection activities and associated research to determine the required quantity and quality of fresh water inflows necessary to maintain various environmental conditions in Texas estuaries to preserve the estuarine ecosystems. These activities are a consequence of a statutory directive to the Board to make provisions in its State Water Plan for the effects of upstream water resource development on the associated estuaries. This paper reports on the results of the first phase of an extensive estuarine research project. The objectives of the research project are to (1) define the interrelationships between estuarine ecosystems and fresh water and nutrient inflows, and (2) develop and test quantitative simulation techniques which describe these relationships. In order to accomplish the first objective, physical and chemical water quality data and biological data on the estuarine ecosystems are being collected, compiled and analyzed. The second objective is being satisfied by the development of hydrodynamic and ecologic simulation models of the estuarine environment.  相似文献   
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