首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
生物吸附剂-海黍子吸附镍   总被引:4,自引:0,他引:4  
采用生物吸附剂-海黍子对重金属镍离子进行吸附,做了动力学实验,得到了海黍子吸附镍的动力学方程。研究了溶液的pH值,初始Ni^2 浓度等因素对Ni^2 的吸附特性的影响,得到最佳pH值4~6及最大吸附量0.8283mmo1/g,并用Langmuir和Freundlich方程对吸附等温线进行了拟合,用Langmuir方程拟合相关系数R^2达0.999以上。  相似文献   

2.
外来红树植物无瓣海桑的入侵生态特征   总被引:1,自引:0,他引:1  
无瓣海桑因其具有速生性的特点而被广泛的用于滩涂海岸造林和控制外来杂草互花米草。但是同样作为外来种,无瓣海桑其自身的入侵性及生态风险已经成为近年来研究的一大热点。依据外来种风险评估的侧重点,分别从定居特性、传播特性及其影响等方面总结了国内外无瓣海桑的入侵生态特征的相关研究,表明无瓣海桑具有速生、高生产力、对低温和土壤具有一定的适应性、已在澳门等地出现扩散入侵现象等利于入侵的特点;但是同时它生态位宽度中等,繁殖率较低,并且它的种植会改善红树林生态系统土壤养分,有利于乡土红树植物的生长。现有对无瓣海桑入侵生态特征的定性研究并不能完全确定其入侵性和生态风险。因此今后需采用风险评估模型等手段对无瓣海桑入侵性进行更为深入地评估。  相似文献   

3.
无瓣海桑(Sonneratia apetala Buch.Ham)是中国沿海地区常用的红树林造林树种。然而,目前对其根系的空间分布特征仍知之甚少,以下基础性问题仍急待回答:无瓣海桑地表根系和地下根系的空间分布特征如何?这些特征随林龄如何变化?这些根系空间分布特征能为理解无瓣海桑促淤保滩、防风消浪等功能提供哪些启示?选择北部湾13 a、8 a、5 a、3 a 4种龄期的无瓣海桑人工纯林,采用地表根系网格法和壕沟挖掘法,调查了4种林龄下无瓣海桑的水平根系分布幅度、根系深度、地表根密度、高度与基径、地下根系的垂直分布,研究了无瓣海桑植株根系空间分布特征及随树龄的变化规律。研究结果表明:(1)无瓣海桑植株地表根系水平分布范围随树龄增加而不断扩大,13 a、8 a、5 a、3 a无瓣海桑植株地表根系水平分布范围分别是79.20、45.80、18.40、14.64 m,分别是其冠幅的14.46、8.90、5.62、5.52倍;(2)4种林龄的无瓣海桑植株地表呼吸根系的密度、高度、基径在水平方向上由冠幅向外逐渐减小;(3)无瓣海桑植株地下垂直根系分布的深度十分有限,13 a与8 a无瓣海桑根系垂直分布深度为0~60 cm,5 a和3 a为0~40 cm;另外0~20 cm土壤深度为根系主要分布深度,13 a、8 a、5 a、3 a无瓣海桑在0~20 cm分别分布着79.3%、87.6%、93.0%、94.1%的根系。研究结果不仅有助于加强对无瓣海桑根系时空分布特性的理解,而且能从根系角度为进一步理解无瓣海桑促淤保滩、防风消浪等功能提供新解释。  相似文献   

4.
为揭示不同植物群落土壤在无瓣海桑(Sonneratia apetala)控制互花米草(Spartina alterniflora)中的作用,利用化感生物测定的方法,选用黑麦草(Lolium perenne)为受体,对比分析红树林无瓣海桑群落、互花米草群落以及无瓣海桑+互花米草群落土壤水提液的化感作用大小。结果表明3,种植物群落土壤水提液对黑麦草具有化感作用,无瓣海桑群落土壤和无瓣海桑+互花米草群落土壤水提液对黑麦草根长和苗高的影响表现出低促高抑的现象;ρ为0.25 g·mL-1的土壤水提液对黑麦草种子发芽和幼苗生长影响不大,1.0 g·mL-1土壤水提液对黑麦草根长和苗高产生显著影响,加入活性碳之后能减弱水提液的化感作用。ρ为0.25或0.5 g·mL-1条件下3,种土壤浸提液对黑麦草发芽率的影响无显著差异;ρ为1.0 g·mL-1的3种水提液都显著抑制黑麦草根长,而无瓣海桑群落土壤水提液表现出更强的化感作用,ρ为1.0 g·mL-1的土壤水提液显著抑制黑麦草苗高,无瓣海桑群落土壤对苗高的抑制作用显著强于互花米草群落土壤(P<0.01)。以黑麦草为受体,无瓣海桑群落土壤化感作用强于互花米草群落土壤,通过根系分...  相似文献   

5.
广东省雷州附城主要红树林群落碳储量及其影响因子   总被引:2,自引:0,他引:2  
红树林生态系统具有碳储量高、碳汇潜力强的特点,选择碳密度高的红树林树种和最佳的碳汇环境有利于实现碳储量的最大化。以广东省雷州半岛附城沿海红树林为研究对象,通过比较不同林龄、不同潮位、不同树种栽种模式红树林群落碳储量,深入研究不同生物因素和环境因素对红树林碳储量的影响。该研究中,红树林碳储量包括植物碳储量和土壤碳储量两部分,植物碳储量通过地上植物、地下植物和凋落物的生物量的测定进行计算,通过测定土壤有机碳来计算土壤碳储量。结果表明,红树林群落碳储量一般具有随树龄增加而持续增大的趋势,主要原因为土壤碳储量不断增加。高潮位红树林碳储量高于低潮位的,潮位因素与树种因素对碳储量的影响具有交互作用,潮位因素对不同树种的影响程度不同。在研究区域内,20年生各群落碳储量排序为:无瓣海桑(S.apetala)-桐花树(A.corniculatum)桐花树(A.corniculatum)+秋茄(K.obovata)无瓣海桑(S.apetala)桐花树(A.corniculatum)无瓣海桑(S.apetala)-白骨壤(A.marina)秋茄(K.obovata)白骨壤(A.marina),碳储量分别为305.52、236.26、178.15、172.96、145.99、136.98、97.42 t·hm~(-2)。本研究可为合理制定红树林碳汇造林方案提供科学依据。  相似文献   

6.
大亚湾海水中的二氧化碳体系   总被引:1,自引:0,他引:1  
对大亚湾四个季节调查表明、大亚湾海水二氧化碳各组份占总碳比例介于河口与外海之间,HCO_3~-/∑CO_2值为0.89,CO_3~(2-)/∑CO_2值为0.11,CO_2/∑CO_2值为0.005。文章描述了二氧化碳各组份在大亚湾的时空变化,进行二氧化碳各组份与盐度的回归分析。得出影响大亚湾海水二氧化碳体系主要因素在春季是低盐水与高盐水的混合;在夏季是上层永和下层水的混合;在冬季则是生物动活。  相似文献   

7.
红树林是海岸的特有植被类型,研究其物种多样性与空间分布,对红树林的恢复与保护具有重要意义。本文以南沙湿地公园红树林为典型案例,采用遥感影像解译和样方调查的方法,对红树林物种多样性、群落特征与空间分布格局进行研究。结果表明:(1)南沙湿地公园红树林物种多样性指数高于其他与之纬度相近的红树林群落;(2)以无瓣海桑Sonneratia apetala Buch-Ham.、桐花树Aegiceras corniculatum(L.)Blanco.、黄槿Hibiscus tiliaceus L.和芦苇Phragmites australis(Cav.)Trin.ex Steud.为优势种;(3)主要的群落类型为无瓣海桑群落、黄槿群落和芦苇群落等3种,总面积百分比达86.72%,无瓣海桑群落和黄槿群落面积占比分别为41.13%和36.44%,成为红树林的绝对优势群落;(4)红树林群落在空间上呈聚集态分布,聚集度最高的是无瓣海桑群落,其次是黄槿群落,面积占比最低的是木榄群落;(5)引进种无瓣海桑,发展态势好,抑制了乡土种红树植物生长。建议扩种白骨壤Avicennia marina(Forsk.)Vierh.、桐花树和秋茄Kandelia candel(L.)Druce.,扩大其斑块面积,以提升乡土红树植物群落的稳定性,达到有效保护红树林的目的。  相似文献   

8.
海莲红树林土壤CH4动态研究   总被引:2,自引:0,他引:2  
对海南东寨港河港河口海莲红树林土壤CH4动态进行研究。CH4通量季节变化规律为春季>夏季>秋季>冬季,所有季节所有滩面其平均值为1.21 mg/(m2d)。不同季节CH4产生量平均值的大小顺序也为春季>夏季>秋季>冬季,所有季节所有滩面其平均值为8.28 mg/(m2d);土壤理化因子对河港海莲林土壤CH4产生率的重要性依次为全氮>NaCl>Na >Cl->SO42->含水量>总含盐量>有机质。暖季CH4氧化量高于冷季,平均值为7.06 mg/(m2d)。在所有季节所有滩面上,河港海莲林土壤CH4传输率的平均值为28.21%。  相似文献   

9.
高校校园中水回用的研究与规划   总被引:22,自引:0,他引:22  
在分析某高校校园中水回用的必要性的基础上,对校园中水回用方案进行了比较,提出最佳适合高校校园中水回用的方案;同时研究了中水回用系统工艺,并对本中水回用项目的经济效益、社会效益和环境效益进行了详细的分析研究。  相似文献   

10.
为了客观公正地评价生态农场的发展状况,运用层次分析法,结合生态农场实际情况,从本地资源、经济效益、社会效益和生态环境效益角度出发,提出了生态农场评价指标体系构建原则和方法,并建立生态农场综合水平评价定性与定量相结合的指标体系,进而运用量化的评价指标体系和层次分析评价法,对湖南省辰溪县橘海生态农场进行了综合评价实证.  相似文献   

11.
酞酸酯的暴露及健康风险研究日趋深入。在综述了酞酸酯的物化性质、接触机会两方面特性,以及体内代谢、健康危害两方面的最新研究进展基础上,比较了其国内外相关标准现状,总结了酞酸酯暴露评估现状及健康风险研究现状,提出并分析了存在的问题,并对其今后的研究进行了展望。  相似文献   

12.
谢晓丽 《生态环境》2002,11(4):352-355
对广州市的荔枝、龙眼和香蕉三大类水果产品质量和生产环境进行了质量监测和评价。结果表明,这三类水果的生产环境均遭受一定程度的污染;水果质量广泛受到氟污染,部分受到Pb、Cd污染;荔枝对镉的吸收富集作用较强。  相似文献   

13.
The electrochemical reduction characteristics of chlorinated hydrocarbons were investigated by cyclic voltammetry technique. The reduction mechanism and activity of the chlorinated hydrocarbons at the copper electrode were explored. The relationship between the structure of chlorinated hydrocarbons and their reductive activity were discussed. The experimental results showed that chlorinated alkanes and a portion of chlorinated aromatic hydrocarbons could be reduced directly at the copper electrode. However, chlorinated aromatic hydrocarbons were not easy to reduce at the copper electrode. The results provided a theoretical basis for the catalyzed iron inner electrolysis method.  相似文献   

14.
A fast, reliable and quantifiable bioassay has been developed to study the factor in the optic gland ofSepia officinalis L. that stimulates mitosis in both gonial and follicle cells. Male germ cells, follicle cells, nidamental and oviducal gland cells of maturing cuttlefish (sampled in 1988 and 1989 in the Bay of Seine) were mechanically and enzymatically dispersed. Incorporation rates of3H thymidine by the dispersed cells and measurements of their aspartate-transcarbamylase activity were used as indicators of mitotic activity. Both assays were stimulated after incubation with optic-gland extracts of haemolymph from maturing individuals. The optimal conditions for the bioassay were determined. The factor stimulating mitosis does not appear to be sex-specific but does display seasonal variations.  相似文献   

15.
The brown alga Fucus ceranoides L. was studied in several estuaries on the Isle of Man (Great Britain) in the summers of 1989 and 1990. The objective were to determine the success of natural fertilization in a dioecious organism with external fertilization and to contribute to our understanding of processes such as polyspermy blocks and propagule settlement under natural conditions. Gamete release occurred on a semilunar cycle near full and new moons; at such times, settlement densities of 500 zygotes cm-2 d-1 were common. Gamete release was largely restricted to daytime high tides. Fertilization success was high: about 95 to 100% of all eggs released were fertilized, and 1 to 9% of these zygotes were polyspermic. The incidence of polyspermy increased towards the upper limit of F. ceranoides in the estuary of the river Neb; this may be significant in the context of the Na+-dependent block against polyspermy. Levels of polyspermy were not related to fertilization success (R2=0.06). Rates of pronuclear migration and karyogamy determined in the laboratory were used as an internal clock to estimate when eggs were fertilized in the field. Most eggs were fertilized 30 to 120 min after plants were immersed by the incoming tide, which corresponded to the period 60 min before to 30 min after high tide. The high success of fertilization suggests that polyspermy blocks are important in nature, and, in combination with the high settlement of zygotes, shows that population size in F. ceranoides is determined by post-settlement mortality, not by propagule availability.  相似文献   

16.
During the end of the phytoplankton spring bloom, about 100 water samples were taken at 23 stations in the Baltic Sea. The samples were analyzed for particulate Cu, Fe, Zn, Cd, and Pb by atomic absorption as well as for chlorophyll and seston. Further subsamples were counted with an inverted microscope, and phytoplankton carbon content was calculated. The hydrographical-biological state of the Baltic Sea during spring is described. Two different water masses could be differentiated and these were separated by the halocline. The concentrations of particulate metals are in accordance with those published by other authors. No significant differences could be calculated between mean values of particulate metal concentrations in the two water bodies. Correlations between particulate metal concentrations and chlorophyll, seston, phytoplankton carbon and cell-count were calculated for both photic layer and deeper waters. Significant correlations were found only in the photic layer. The importance of standing crop for metal accumulation in seston is discussed.  相似文献   

17.
Bright yellow lenses were found in the eyes of the mesopelagic deep-sea fish Argyropelecus affinis Garman. The yellow lenses were studied spectrophotometrically and the eyes were examined histologically. Absorption spectra of the yellow lenses revealed three peaks at wavelengths of 405, 430, and 460 nm. Histological examination revealed the eyes to be typically tubular. The functional significance of the yellow lens in such deep-sea fishes is discussed.  相似文献   

18.
华北平原地下水有机污染特征初步分析   总被引:5,自引:0,他引:5  
各种污染造成地下水中有害物质逐年增加,地下水水质逐渐下降,严重危及了饮用水安全。针对此情况,按照相关的要求,采集了245组水样。样品由有资质的测试单位测定。依据对地下水质调查的初步分析,华北平原地下水中已有机物检出。对所有水样测试结果的统计显示:检出的有机污染物共有32种。检出率大于4.5%的有氯仿、甲苯、四氯乙烯、苯并[a]芘、氯苯、苯和1,2-二氯苯,其中个别水样中的四氯化碳、苯并[a]芘和挥发性酚类三项超过了饮用水标准(据地下水质量标准报批稿,中国地质调查局,2007),超标率分别为1.22%、2.45%和1.90%。个别在深层地下水样品中也检出了微量有机污染物,这可能与取样井的混合开采、止水不佳有关。从区域上来看,在人类活动相对强烈的城镇地区地下水中,有机物检出率相对较高,特别是在渗透性好的山前地带,污染物较易进入到地下水中。通过分析发现,地下水有机物的高检出率与地下水硬度的升高有一定相关性。由于地下水有机污染在时间和空间上差异一般较大,建议对已发现的异常点进行重复取样测试,积累水质数据,以利于将来的综合分析。  相似文献   

19.
The Danjiangkou reservoir was selected to provide the source water for the middle routes of the South to North Water Transfer Project, which has provoked many environmental concerns. To date, investigations of water contamination of the source water of the Danjiangkou reservoir with organic micro-pollutants have been limited. This study was conducted to identify and rank organic contaminants that pose risks in the Danjiangkou reservoir. To this end, the Chemical Hazard Evaluation and Manage- ment Strategies (CHEMS-1) approach was adapted to integrate the deconvolution technology of qualitative identifying contaminants for site-specific environmental matrices. The samples were screened for the presence of 1093 contaminants using deconvolution technologies and the hazard values of the identified contaminants were calculated using the adapted CHEMS-1 approach accord- ing to their hazardous properties and occurrence in source water. The results showed that 46 contaminants from 1093 targets were present in Danjiangkou water, 23 of which appeared at frequencies higher than 50%, and 15 of which were identified as priorities. Over half (53%) of the high- ranked contaminants were polycyclic aromatic hydrocar- bons (PAHs), with chrysene ranked highest on the list. Health risk assessment of the top-ranked PAHs was conducted and revealed that cancer risks of PAHs detected in the source water of Danjiangkou to different populations ranged from 10-7 to 104, indicating a low cancer risk to consumers. The results of this study indicated that the adapted CHEMS-1 approach was feasible for site-specific screening of organic contaminants to identify and rank potential priority pollutants.  相似文献   

20.
Sediment-trap samples were collected during and after the occurrence of a salp (Salpa fusiformis) bloom in the Bay of Villefranche, Mediterranean Sea, in April/May 1985. Large amounts of organic aggregates and faecal pellets were collected during the bloom. The aggregates were rich in carbohydrates and mineral grains and had similar rates of sedimentation (900 to 2 100 m d-1) to those of the faecal pellets (1 000 to 2 000 m d-1). The results of mineralogical and organic chemical analyses indicate the potential effect of these mucus-rich aggregates on local biogeochemical fluxes.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号