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1.
生物扰动对红树林沉积物中AVS和重金属迁移转化的影响   总被引:3,自引:0,他引:3  
张弛  王树功  郑耀辉  陈桂珠 《生态学报》2010,30(11):3037-3045
红树林湿地是我国南方沿海地区极为重要的海岸生态环境系统之一,国内目前针对红树林湿地的研究主要集中于其生态系统功能,沉积物中重金属离子的生物可利用性等,却少有研究关注红树林生态系统中重要的生境改造者植物和蟹类对沉积物的生物扰动效应。从红树林湿地生态系统的植物根系和蟹类两方面,总结归纳了生物扰动对沉积物理化性质、AVS和重金属迁移转化行为的影响。具体包括生物扰动对沉积物的结构、含氧量、有机质、AVS、重金属和硫/铁离子的地化行为的影响效应等。在分析植物根系、蟹类行为对沉积物中重金属的重要结合态——AVS的影响效应的基础上,探讨了这些研究领域之间的相互联系,从而为进一步开展红树林沉积物中生物扰动、AVS及重金属地化行为的科学研究提供理论参考。  相似文献   

2.
富营养化水体沉积物中磷的释放及其影响因素   总被引:76,自引:5,他引:71  
综述了富营养化水体沉积物中磷的化学形态、释放规律及其影响因素。化学形态分为水溶性磷、铝磷、铁磷、钙磷、还原态可溶性磷、闭蓄磷、有机磷等 7种 ,其分布取决于各形态磷的性质。磷释放受 7种因素影响 ,厌氧、高 pH或低 pH值、高温、扰动、生物活动、底泥与水体含磷量的浓度差值以及钙质沉积物组分等因素均能促进沉积物中磷的释放。  相似文献   

3.
水体沉积物中酸挥发性硫化物的研究进展   总被引:13,自引:0,他引:13  
近年来 ,对沉积物特性的研究使人们逐步认识到建立沉积物质量标准以补充水质标准之不足的必要性和重要性 ,国际上有不少学者致力于建立沉积物质量基准 (SQC)的研究工作。利用平衡分配理论对疏水性有机污染物的沉积物毒性阈值研究已取得突破性进展 ,但对毒性金属 ,因其在沉积环境中更复杂的化学分配行为 ,至今研究结果仍存争议。1 990年 ,DiToro首次报道了水体沉积物中酸挥发性硫化物 (AVS ,Acidvolatilesul fide)对Cd的生物有效性的强烈影响[1]。之后 ,沉积物中的AVS已成为研究水环境重金属质量评价的…  相似文献   

4.
生物炭对污染物的土壤环境行为影响研究进展   总被引:10,自引:0,他引:10  
近年来,生物炭已成为农业、生态修复和环境保护领域的研究热点。一般认为,生物炭具有改善土壤质量、增加土壤碳汇、减少大气CO2浓度以及修复污染环境等功能。大量的生物炭施用到土壤后会改变土壤性质,影响重金属和有机污染物在土壤中的环境行为以及它们在环境中的归趋。本文就生物炭对土壤中重金属的吸附-解吸、在土壤中的形态转化、在土壤-植物系统中迁移行为、对有机污染物的吸附挥发及生物有效性进行了概述;在此基础上,扼要分析了当前生物炭应用存在的环境风险等问题,并从生物炭在土壤中的迁移转化及其归趋、生物炭的长期环境效应以及生物炭应用方向等方面进行了展望。  相似文献   

5.
通过对不同富营养化程度的湖泊(滇池及红枫湖)沉积柱剖面进行不同形态磷以及生物硅含量分析,对比了磷及生物硅的沉积分布特征,并探讨了其与湖泊富营养化演化的关系。结果表明:滇池沉积物中碎屑磷和有机磷在总磷中占50.5%~80.8%,是影响总磷趋势的主要原因;红枫湖中有机磷对总磷的贡献较大,占总磷的53%~60.9%;且两湖各形态磷均随深度的增加而减少;两湖总磷、有机磷、铝磷以及滇池沉积柱中的碎屑磷等的快速增长,表明其主要来源于人为污染;生物硅含量呈现从下层沉积物向上逐渐增加,在上层沉积物中逐渐减少的趋势;总磷、有机磷、铁结合态磷、铝结合态磷、弱结合态磷以及生物硅都能较好地反映富营养化污染的演变和现状。  相似文献   

6.
生物吸附剂对污染物吸附的细胞学机理   总被引:3,自引:0,他引:3  
蔡佳亮  黄艺  礼晓 《生态学杂志》2008,27(6):1005-1011
重金属和持久性有机污染物在自然界中非常稳定,具有难去除性,对人类生命和健康会造成直接或间接的危害.目前,生物吸附剂已成为处理重金属和持久性有机污染物研究的热点和重点.本文根据近年来的研究成果对生物吸附剂进行了系统分类,阐述了生物吸附剂对重金属和持久性有机污染物吸附的细胞外、细胞表面和细胞内吸附机理,以及相关的影响因素.同时,还探讨了其研究现状中所存在的问题和未来的研究方向.  相似文献   

7.
深水湖泊经历氧化及还原环境的交替变化,影响着湖泊水体氮的生物地球化学过程;其底层沉积物中一般具有特有的还原环境,其间氮的生物地球化学转化过程复杂。本文以云贵高原典型深水湖泊百花湖为例,在湖泊水体夏季分层期采集底层沉积物柱体,将沉积物柱体分层处理后,对不同深度沉积物中孔隙水、水溶态和吸附态不同形态氮含量,以及沉积物中颗粒态有机氮(PON)含量和同位素进行分析。结果表明,沉积物柱体孔隙水中的总氮(TN)主要由NH4+-N和有机氮两种形式存在,TN含量为6.9~42.8 mg·L-1,NH4+-N含量为6.6~25.6 mg·L-1。硝态氮及亚硝态氮含量均低于检测限,说明沉积物中硝酸盐经历了充分的反硝化过程以及可能存在的异化还原过程。吸附态NH4+-N含量明显高于水溶态。沉积物中的颗粒有机氮含量为0.22%~0.60%。同时,颗粒有机氮含量在剖面上的变化趋势符合指数衰减模式,表明颗粒态有机氮含量的变化可能经历成岩作用和微生物矿化过程;δ15N-PON值在31 cm以上随着深度的加深逐渐减小,变化范围为3.4‰~10.0‰,平均值为6.4‰,其中以10 cm以上同位素值降低趋势明显,其可能原因与微生物降解活动以及湖泊水体的交换有关。31 cm以下δ15N-PON值的变化趋势与表层相反,则可能是早期成岩作用影响的结果。孔隙水中δ15N-TN同位素值最高,吸附态和水溶态差异较小,且该同位素组成较PON富集15N,可推测孔隙水剖面NH4+-N浓度的升高可能与硝酸盐的异化还原有关。  相似文献   

8.
沉积物氮形态与测定方法研究进展   总被引:8,自引:0,他引:8       下载免费PDF全文
刘波  周锋  王国祥  许宽  杜旭  凌芬  夏劲 《生态学报》2011,31(22):6947-6958
长期以来,国内外学者对沉积物中氮进行了大量的研究,在氮生物地球化学循环和生态学效应方面取得了重要进展.然而,现有关于氮赋存形态的研究主要集中在总氮和无机氮方面,还不能深入阐明沉积物氮的生物和生态学机制.分析了沉积物和土壤氮赋存形态划分和测定方法的研究进展,研究表明:沉积物氮的形态划分与测定方法基本上还是借鉴了土壤氮的研究方法;无机态氮的研究多集中在可交换态氮方面,对固定铵的研究相对较少;在可交换态氮提取方法上并没有针对沉积物与土壤的差异进行必要的论证和改进,沉积物中可溶态氮对可交换态氮测定的影响还不明确;有机氮的测定方法基本上是经验方法,目前还无针对有机氮生态学效应的分类及测定方法;连续分级浸提方法从生态学效应的角度对沉积物氮的研究进行了有益的探索,为深入揭示氮的生态学机制提供了新的思路,但是此类方法目前还集中在国内学者的相关研究中.  相似文献   

9.
根系分泌物及其在植物修复中的作用   总被引:53,自引:0,他引:53       下载免费PDF全文
 近年来环境污染日益严重,污染物在土壤植物中的行为引起了人们的高度关注。利用植物去除土壤水体等介质中污染物的植物修复是近10年来兴起的一项安全、廉价的技术,已成为污染生态学和环境生态学的研究热点,它通过植物吸收、根滤、稳定、挥发等方式清除环境中的重金属和有机污染物。国内外有关植物修复的研究报道和概述很多, 但对植物根系分泌物在植物修复中所起的作用及其机理少有述评。 本文从根系分泌物对土壤重金属和土壤有机污染物的去除作用出发,对根系分泌物的种类、数量及其在去除环境污染物中的作用机理和功能地位进行了总结,并借助研究事例对影响植物根系分泌的内外因子,如植物种类、营养胁迫、重金属胁迫、根际环境的理化性质、土壤微生物及其它环境因子进行了讨论。概言之,根系分泌物在修复污染土壤中的重金属途径是多种多样的,主要是通过调节根际pH值、与重金属形成螯合物、络合反应、沉淀、提高土壤微生物数量和活性来改变重金属在根际中的存在形态以及提高重金属的生物有效性,从而减轻它对环境的危害。在清除有机污染物时,根系分泌物中的酶可以对有机污染物进行直接降解,根系分泌物影响下的微生物也可以对有机污染物进行间接降解,且被认为是主要的降解途径。根系分泌物在植物修复过程中确实起着某些重要作用,今后应将这方面的研究重点放在某些特异性根系分泌物植物,尤其是某些重金属超富集植物资源的寻找、筛选上,通过室内实验和野外研究确定其根系分泌物对清除重金属和有机污染物的效率,证实超富集植物根系分泌物的特异性与污染物超富集的内在联系,找到污染土壤生态恢复和治理的有效方法并加以推广应用,如针对性地在被污染地大面积种植此类具特异性根分泌物植物,并辅以营林措施如修剪等,加快生物修复进程,提高修复效率。植物根系分泌物在植物修复过程中所具有的重要生态意义和可能应用前景,为污染生态学和化学生态学之间的联合研究开拓了全新的领域,今后将取得新的突破和重要进展。  相似文献   

10.
环境因子对杭州西湖沉积物各形态磷释放的影响   总被引:1,自引:0,他引:1  
对西湖沉积物的磷形态、粒径组成、化学组成进行了分析, 模拟研究了上覆水磷含量、光照、pH、温度、水动力条件等不同环境因子对西湖沉积物各形态磷释放的影响。结果表明, 上覆水为蒸馏水时的最大释磷量约为底泥-湖水系统的1.15倍, 且释放形态均以IP中的Fe/Al-P为主。在蔽光条件下的最大TP释放量约为光照条件下最大TP释放量的1.35倍。pH 是影响磷释放的重要因素, 在碱性条件下, 促进Fe/Al-P的释放; 在酸性条件下, 促进Ca-P 的释放。在高温条件下沉积物的释磷量会高于低温条件下的释磷量。沉积物各形态磷的释放量在15h后逐渐趋于平衡扰动状态达到平衡时TP释放量是静态释放平衡状态的1.61倍。研究结果旨在探讨不同环境因子对湖泊沉积物磷迁移转化的生态环境效应, 预测西湖内源磷释放的发展趋势, 为控制沉积物内源污染提供理论基础。  相似文献   

11.
依据长江口滨岸潮滩大型底栖动物的自然分布特征,选取了两段典型的研究区域——崇明东部潮滩和浒浦岸段边滩,运用实验模拟和对比分析方法,定量地研究了大型底栖动物谭氏泥蟹和河蚬对潮滩生态系统中氮营养盐的界面扩散及其早期成岩变化的影响。研究表明,谭氏泥蟹主要通过掘穴活动增加沉积物-水-气三相接触界面,促进沉积物中的无机氮(NH 4- N、NO- 2 -N和NO- 3- N)向上覆水体中扩散,并且也加快了沉积物中氮的氨化作用和硝化作用速率,而河蚬则主要通过生理活动机制影响潮滩生态系统内氮素的迁移转化过程。研究结果深刻揭示了大型底栖动物通过生物扰动和生理活动作用机制,促进了长江口潮滩生态系统内氮素的生物地球化学循环过程速率。  相似文献   

12.
The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns: the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the gastropod Cyclope neritea, a burrowing species which does not build any structure. Oxygen two-dimensional distribution in sediments was quantified by means of the optical planar optode technique. Diffusive oxygen fluxes (mean and integrated) and a variability index were calculated on the captured oxygen images. All species increased sediment oxygen heterogeneity compared to the controls without animals. This was particularly noticeable with the polychaetes because of the construction of more or less complex burrows. Integrated diffusive oxygen flux increased with oxygen heterogeneity due to the production of interface available for solute exchanges between overlying water and sediments. This work shows that sediment heterogeneity is an important feature of the control of oxygen exchanges at the sediment-water interface.  相似文献   

13.
Exchange of phosphorus across the sediment-water interface   总被引:55,自引:21,他引:34  
In this article, principles of phosphorus retention and phosphorus release at the sediment-water interface in lakes are reviewed. New results and hypotheses are discussed in relation to older models of phosphorus exchange between sediments and water. The fractional composition of sedimentary phosphorus is discussed as a tool for interpretation of different retention mechanisms. Special emphasis is given to the impact of biological, particularly microbial, processes on phosphorus exchange across the sediment-water interface and to the significance of biologically induced CaCO3 precipitation to phosphorus retention in calcareous lakes.  相似文献   

14.
Robbins  J. A. 《Hydrobiologia》1982,91(1):611-622
Recent sediments of the North American Great Lakes are inhabited by numerous species of macrobenthos which alter the physical and chemical properties of sediments and modify interface transport characteristics. Distributions of such radionuclides as cesium-137, lead-210, and isotopes of plutonium exhibit a zone of constant activity extending down from the sediment-water interface from 1 to 15 cm. Recent studies have confirmed that radiometrically determined mixed depths are consistent with the vertical distribution of oligochaete worms and the amphipod,Pontoporeia hoyi. Generally, 90% of the benthos are contained within the radiometrically defined mixed zone. Where comparisons are possible, rates of sediment reworking by ‘conveyor belt’ species are comparable to or exceed sedimentation rates. Systematic variations in the mixed depth occur within depositional basins with greatest depths tending to be associated with least consolidated, organically rich materials. A quantitative steady-state mixing model accounts satisfactorily for observed radioactivity and heavy metal profiles. Bioturbation appears to be an important process, limiting the resolution with which historical records of particle-associated contaminants may be reconstructed from sediment cores. As bioturbation serves to maintain contact of contaminated sediments with overlying water, this time may also characterize the long-term lake recovery for contaminants removed by burial. As the time varies with location, a mean for an entire lake is not well known, but is on the order of 20 years for Lake Huron. Contribution No. 300 of the Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan.  相似文献   

15.
Considerations in modeling the sediment-water exchange of phosphorus   总被引:1,自引:0,他引:1  
The potential to release accumulated phosphorus from sediments has been the major motive to study and to model the fate of this nutrient in sediments. For the dynamics of the sediment-water interaction the sizes of the pools involved and the rates of conversion/transport from one pool to another are of primary interest. As the sediment pools for phosphate are generally much larger than the pools in the water column, a rather slow adjustment of the sediment to management measures will occur. For the analysis of management measures it is obvious that the gradual change in sediment composition must be taken into account. Only for rather short periods the sediment composition can be assumed to be constant; this may be appropriate for studies of e.g. the annual cycle. The sediment-water interaction is a complex resultant of physical, chemical and biological processes, including:
  • physical processes: advection due to seepage or consolidation, pore-water diffusion, transport and mixing of solids by resuspension, sedimentation and bioturbation.
  • chemical processes: adsorption and desorption, dissolution and (co)precipitation, inclusion.
  • biological processes: mineralization of a wide range of organic compounds by various (micro)organisms, each with their own nutrient requirements and electron acceptors.
  • Aspects which are discussed and need to be considered in application of a model in research or management are the level of aggregation and detail that is required and may still be practical, the spatial and temporal scales which are applicable for the processes mentioned and their influence upon the numerical dispersion and model stability, the availability of data for calibration/validation and the resolution of the analytical techniques. These aspects are not independent however. Frequently models are not functional because they contain details which are either unnecessary or suggest a feigned accuracy which is not justified by analytical and experimental resolution of system characteristics.  相似文献   

    16.
    SUMMARY. 1. Pore water chemistry in peaty sediment was monitored for a year at two representative locations of the eutrophic shallow Loosdrecht lakes. The Netherlands. Phosphorus fluxes over the sediment-water interface were calculated using measured concentration gradients in the pore water and compared to fluxes measured under laboratory conditions. Results were analysed with Redundancy Analysis to detect patterns of variation in pore water chemistry and in measured and calculated fluxes, that could be ascribed to environmental variables.
    2. It was demonstrated that phosphorus fluxes measured in long-term laboratory incubations were not correlated to any of the pore water characteristics.
    3. Initial phosphorus fluxes measured in sediment columns, which varied between −7.7 and 1330 μmol m−2: day−1, were correlated significantly to the calculated phosphorus flux over the sediment-water interface.
    4. The high correlation between calculated fluxes of ammonia, phosphorus and methane and measured initial flux of phosphorus, conclusively pointed to mineralization of organic matter as the driving force for phosphorus release from the sediment.
    5. Redundancy Analysis demonstrated that the rates of mineralization and phosphorus release were only weakly related to temperature. They appeared to be especially stimulated by the autumnal decrease in temperature which was probably related to an extra input of organic matter.  相似文献   

    17.
    Biogeochemistry of manganese- and iron-rich sediments in Toolik Lake,Alaska   总被引:2,自引:2,他引:0  
    The sediments within Toolik Lake in arctic Alaska are characterized by extremely low rates of organic matter sedimentation and unusually high concentrations of iron and manganese. Pore water and solid phase measurements of iron, manganese, trace metals, carbon, nitrogen, phosphorus, and sulfur are consistent with the hypothesis that the reduction of organic matter by iron and manganese is the most important biogeochemical reaction within the sediment. Very low rates of dissolved oxygen consumption by the sediments result in an oxidizing environment at the sediment-water interface. This results in high retention of upwardly-diffusing iron and manganese and the formation of metal-enriched sediment. Phosphate in sediment pore waters is strongly adsorbed by the metal-enriched phases. Consequently, fluxes of phosphorus from the sediments to overlying waters are very small and contribute to the oligotrophic nature of the Toolik Lake aquatic system. Toolik Lake contains an unusual type of lacustrine sediment, and in many ways the sediments are similar to those found in oligotrophic oceanic environments.  相似文献   

    18.
    水丝蚓对太湖沉积物有机磷组成及垂向分布的影响   总被引:5,自引:0,他引:5  
    白秀玲  周云凯  张雷 《生态学报》2012,32(17):5581-5588
    以太湖常见底栖动物——水丝蚓为研究对象,借助室内流动培养装置和31P核磁共振技术(phosphorus-31 nuclearmagnetic resonance spectroscopy)(31P-NMR),研究生物扰动对太湖沉积物有机磷组成及垂向分布的影响。结果表明:短时间内水丝蚓扰动对沉积物有机磷化合物种类组成影响并不显著,但会引起上层沉积物中稳定性较差的有机磷化合物磷脂和DNA含量出现显著降低,同时沉积物中总磷和有机磷的垂向分布亦发生明显改变。此外,水丝蚓扰动下沉积物含水率、孔隙率和碱性磷酸酶活性显著增加,使活性较高的有机磷化合物分解加速,最终导致表层沉积物中的磷脂与DNA含量降低。  相似文献   

    19.
    全氟辛酸(PFOA)是一种重要的全氟化表面活性剂,具有环境持久性、高毒性和生物累积性等特征,成为当前备受关注的新污染物。沉积物是PFOA的重要环境储蓄库,被污染后的沉积物可作为长期污染源造成上覆地表水及周边地下水污染。本文结合近年来国内外研究,对地表水和沉积物中PFOA的来源、污染现状和界面吸附迁移行为进行了综述。结果表明: 地表水体和沉积物中PFOA最主要的污染来源为工业废水排放。全球范围地表水体和沉积物中PFOA污染水平普遍为ng·g-1和ng·L-1数量级,且国内部分地区污染形势更为严峻。沉积物组分、水化学条件、有机质及表面活性剂等因素均影响沉积物中PFOA的吸附行为,但目前在吸附主控机制方面仍然存在争议。沉积物中PFOA迁移行为的研究正处于起步阶段,相关报导还较为缺乏,对于迁移机理的认识还很不足,今后需在该方面加大研究力度。  相似文献   

    20.
    Phosphorus release from the sediments of very shallow lakes, the Norfolk Broads, can be as high as 278 mgP m-2 d-1. These high rates are associated with high total sediment Fe:P ratios and occur when sulphide from sulphate reduction removes Fe(II) from the pore water. There is also evidence that bioturbation from benthic chironomids can enhance phosphorus release rates, particularly in sediments low in total iron. The release of phosphorus from the sediments of these lakes is delaying restoration following the control of phosphorus from sewage discharges. Biomanipulation is being used in these lakes to create clear water and re-establish aquatic macrophytes. This removal of fish has allowed larger populations of benthic chironomid larvae to develop which may result in an increase in the rate of phosphorus release and changes to the pore profiles of dissolved phosphorus, soluble iron and free sulphide.  相似文献   

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