This paper is a review of research works concerning the nutrient transportation, transformation and exchange between water, sediment and biota in the lakes from the middle and lower reaches of the Yangtze River conducted in the context of project entitled “The Processes and Mechanism of Lake Eutrophication in Middle and Lower Reaches of Yangtze River”. All the lakes from this area are shallow lakes. According to the typical lake site research, the lakes from the middle and lower reaches of Yangtze River have a higher baseline of nutrition in the history. Normally the trophic status of these lakes can be categorized into medium-trophic or eutrophic Human activities have been enhanced during the last decades, which speed up the lake eutrophic process. Lake eutrophication control needs to reduce not only the external nutrient inputs from watershed but also the internal loading from the sediments. Investigations revealed that the lake sediments in this area are considerablly high in nutrition in which at most about 30% of phosphorus exists in the form of bio-available in the sediment. The surface sediment will exert great effects on the nutrient exchange between water-sediment interface via adsorption and release of nutrient. The nutrient release from the sediment in these shallow lakes is mainly in two ways, i.e. in the undisturbed condition the nutrient is released through diffusion created by the nutrient gradient from sediment to overlying water; whereas in disturbed condition, the nutrient release is determined by the hydrodynamic forcing intensity and the sediment resuspension. Metallic elements such as the iron, manganese and aluminium and the aerobic-anaerobic ambience will affect the release of nutrients. The disturbed release will increase the total nutrients in the water column significantly in the short period. At the beginning of sediment resuspension, the dissolved nutrient concentration will increase. This increase will be damped if the ferric oxide and aluminium are rich in sediment because of the adsorption and flocculation. This means that the lakes have capability of eliminating the nutrient loadings. Investigations for the lakes from middle and down stream of Yangtze River have suggested that most lakes have the self-cleaning capability. Dredging the control of the internal loading, therefore, is only applicable to the small lakes or undisturbed bays which normally are situated nearby the city or town and rich in organic materials in the sediment. In addition, the strong reduction condition and weak aeration of these lakes and bays make these small lakes and bays release much more bio-available nutrient and without much self-eliminating capability. Moreover, eutrophication induced algal bloom in these lakes will change the pH of water, which further induces the increase in the nutrient release. In turn, the increase in nutrient release promotes the growth of phytoplankton and results in severe algal bloom. For the heavily polluted water, research suggests that the biomass of bacteria and alkaline phosphatase activity will be higher corresponding to the higher concentration of nutrients, which accelerates the nutrient recycling between water, sediment and biota. Quick recycling of nutrient, in turn, promotes the production and biomass growth of microorganism and leads to more severe eutrophication. Further research work should focus on the nutrient transformation mechanism and the effects of microbial loop on the eutrophication.
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1.
长江中下游地区湖泊水和沉积物中营养盐的赋存、循环及其交换特征 总被引：15，自引：0，他引：15
回顾了有关长江中下游地区湖泊水、生物、沉积物中营养盐的迁移、转化、循环和交换等研究工作进展.典型湖泊的研究结果显示,历史上长江中下游地区湖泊的营养本底的确较高,处于中营养和富营养状态;人类活动在最近几十年中加快了这些湖泊的富营养化进程.长江中下游地区湖泊的治理不仅要重视外源污染的削减,也要重视湖泊内源污染的控制.长江中下游地区的浅水湖泊沉积物中,一般只有30％以下的磷是以较活跃的藻类易利用态存在的,表层沉积物通过吸附-解吸等交换作用对浅水湖泊水体中磷的浓度有较大的影响.长江中下游浅水湖泊沉积物中的营养盐释放主要有静态和动态二种释放方式.前者是基于化学平衡条件下的水土界面扩散作用.决定其释放量大小的主要因子是孔隙水与上覆水之间的营养盐浓度差.后者是基于水动力扰动对水土界面物理破坏条件下的底泥悬浮释放作用.二种释放模式在浅水水体中都存在.无论是静态或动态,水土界面的氧化还原环境,铁、锰、铝等元素含量,都对释放有影响.动态释放能在短期内大大提高水体颗粒态营养盐的浓度.在动态释放的初期,将有效增加水体可溶性营养盐,但是如果沉积物中铁、铝等金属元素较丰富,水体中的溶解性营养盐将由于吸附等作用而沉淀至湖底,因此,这样的湖泊往往具有较强的自我净化能力.长江中下游地区绝大多数湖泊都属于这种类型的湖泊.用底泥疏浚方法来控制湖泊内源污染的方法只适用湖泊面积较小、还原环境强烈,或者沉积物中铁、锰含量较低、水体去除可溶性营养盐的能力较弱的水体.此外,长江中下游地区的浅水湖泊生态系统对富营养化也具有强烈的反馈作用.水华暴发期间蓝藻的暴发性生长能通过改变水体的pH而引发沉积物中磷释放数量的大幅增加,大量释放的营养盐反过来又会促使蓝藻的大量生长,从而加剧水华的暴发.研究显示污染相对较重的水域水体中营养盐的含量高,微生物的生物量及生产力也高,碱性磷酸酶的活性也高,水体营养盐的循环也就更快.这反过来又促使微生物生产力增加,营养盐循环更快,加剧富营养化的危害.今后的工作应该重点围绕生物参与下营养盐的迁移转化等方面开展工作. 相似文献
2.
福建闽江水口库区飘浮植物覆盖对水体环境的影响 总被引：18，自引：0，他引：18
为了探索城市富营养化湖泊生态修复技术,2000年9月在南京市莫愁湖物理生态工程试验区内,开展了隔离外源污染、覆盖底泥和种植水生植物对湖泊水质平均水平和水体脉动强度影响的比较研究．试验结果表明,通过围隔隔离外源污染可在较短时间内迅速改善湖泊TN的平均水平,但难以提高湖泊生态系统的稳定性;通过覆盖底泥控制内源污染难以改善湖泊水质的平均水平,并且难以提高湖泊生态系统的稳定程度;种植水生植物不仅能够全面改善湖泊水质的平均水平,而且可以提高湖泊生态系统的稳定性．此外,富营养化湖泊中,藻类生长与湖水营养盐浓度并不存在正相关的关系．因此,对城市湖泊富营养化的防治,在控制外源污染降低营养盐浓度的同时,应恢复湖泊原有的以水生高等植物为主的生态系统． 相似文献
3.
太湖生态与环境若干问题的研究进展及其展望 总被引：30，自引：5，他引：25
本文着重就太湖水动力及其生态环境效应、太湖沉积物及其内源污染问题和太湖生态系统结构与功能及其蓝藻水华等热点问题近十年来的研究进展进行了回顾.在水动力及其生态环境效应方面,初步摸索出一套适合太湖这样大型浅水湖泊的研究方法,即通过沉积物悬浮过程的研究,把风浪与水体光照透明度、内源释放、水土界面的氧化还原环境等过程和要素联系起来,获得了太湖理化要素随深度变化的内部结构特征,确立了三维水动力模拟模型在太湖应用中的必要性.建立了太湖光照和透明度与悬浮物的关系,及基于悬浮物浓度的太朔初级生产力计算模型.在太湖沉积物与内源污染问题上,初步弄清了太湖沉积物分布与污染物质分布的特征,太湖沉积物悬浮的动力作用的来源与大小.太湖水动力对内源释放的影响,进一步提出了适于太湖内源污染控制的判断方法.对于太湖生态系统结构与功能及其蓝藻水华问题,在蓝藻水华爆发过程假设的基础上,进一步通过营养盐阈值、休眠孢子复苏等方面对此进行了完善.研究还发现了富营养化导致生态系统退化,生物趋于小型化且多样性下降的现象,营养盐循环速率加快,加重水体富营养化程度.进一步通过附着生物的研究,揭示了富营养化导致草型生态系统向藻型生态系统转化的原因.在此基础上,提出了生态恢复应该首先降低营养盐负荷、其次才是生态恢复的新观念,以及湖泊治理必须先控源截污、后生态恢复的新思路.最后,就这几个方面的进一步发展做出了展望. 相似文献
4.
大型浅水湖泊沉积物内源营养盐释放模式及其估算方法--以太湖为例 总被引：27，自引：1，他引：26
在新的野外调查和室内试验基础上,完善了有关大型浅水湖泊沉积物内源营养盐释放的模式,并在此基础上提出了太湖内源释放的估算方法.通过在太湖开展室内释放模拟实验和风浪期间底泥悬浮及上覆水中营养盐浓度变化的野外观测,提出了静态与动态二种浅水湖泊内源释放模式.静态情况下,营养盐主要通过浓度梯度扩散从沉积物进入上覆水,其释放强度受控于沉积物～水界面的温度,氧化还原环境及营养盐浓度差;动态条件下,沉积物由于动力扰动而发生悬浮,沉积物中溶解性及颗粒态的营养盐随着沉积物的悬浮而释放.虽然动态情况下总的营养盐释放较静态条件下大,但由于湍流导致水体及水土界面充氧,铁,锰等金属元素因氧化而吸附溶解性营养盐(特别是活性磷SRP)的能力增强,所以动力扰动仅引起总的营养盐释放,而不一定导致溶解性营养盐的释放.因此,在动态条件下,营养盐总释放量受控于动力扰动强度,底泥可悬浮量及沉积物中的营养盐含量;对于可溶性的营养盐,特别是SRP,其释放还受控于动力复氧的强度,沉积物中铁的含量及沉积物间隙水与上覆水中营养盐的浓度差.在此基础上,分别估算了静态和动态二种情况下沉积物内源释放量.根据实验室模拟结果,静态条件下太湖全湖一年NH4+-N释放量达1万吨左右,PO43--p释放量达900t左右;结合太湖2001年的风场观测记录,把太湖野外风浪过程分为风平浪静,小风浪,大风浪三种情况,分别占全年总日数的12％,82％,6％.在"风平浪静"条件下,其释放量根据实验室的静态释放试验来估算,而"小风浪"和"大风浪"条件下,其释放量则根据室内水槽试验得到的释放通量来估算.结果显示太湖全年释放量为总氮8.1万吨,总磷为2.1万吨;分别为外源氮磷年输入量的2～6倍. 相似文献
5.
浅水湖泊底栖-敞水生境耦合对富营养化的响应与稳态转换机理:对湖泊修复的启示 总被引：1，自引：0，他引：1
浅水湖泊中的初级生产者主要由分布在底栖生境中的底栖植物和生活在敞水生境中的浮游植物组成.底栖植物主要包括维管束沉水植物和底栖藻类等,浮游植物则主要为浮游藻类.贫营养浅水湖泊湖水营养盐浓度低,透明度高,底栖植物因能直接从沉积物中获取营养盐,往往是浅水湖泊的优势初级生产者.随着外源营养盐负荷的增加,湖水中的营养盐浓度不断升高,浮游植物受到的营养盐限制作用减小,加上其在光照方面的竞争优势,逐步发展成为湖泊的优势初级生产者,湖泊逐步从底栖植物为优势的清水态转变为浮游植物为主的浑水态,即稳态转换.在稳态转换过程中,浅水湖泊生态系统结构与功能发生了一系列变化,本文综述了浅水湖泊沉积物性质和生物(浮游植物、底栖植物、底栖动物和鱼类等)群落结构的变化,分析了这些变化对底栖植物、浮游植物之间竞争优势和底栖敞水生境间磷交换的影响,探讨了富营养化驱动的底栖敞水生境耦合过程变化和稳态转换机理.了解浅水湖泊底栖敞水生境耦合过程与稳态转换机理对富营养化浅水湖泊修复有重要意义.富营养化浅水湖泊修复实际就是重建其清水态,在制定修复目标时应该关注评价清水态的指标,如透明度、浮游植物生物量、底栖植物的覆盖度或优势度等.在开展湖泊修复技术研发与工程应用时,应该重点关注对底栖敞水生境耦合有重要影响的关键技术,如沉积物磷释放和底栖生物食性鱼类控制以及底栖植物(尤其是沉水植物)恢复等有关技术. 相似文献
6.
分析了生物操纵(biomanipulation)和非经典生物操纵(non-traditional biomanipulation)理论的原理、应用条件及局限性,提出了在局部水体治理湖泊富营养化的对策.分析认为:生物操纵的核心内容是利用浮游动物控制藻类;但浮游动物不能有效控制丝状藻类和形成群体的蓝藻水华;我国的大型浅水湖泊浮游动物数量一般并不多,对浮游植物摄食压力不大;在浅水湖泊,浮游动物摄食藻类后很快分解、释放又进入物质循环,因此不能治理湖泊富营养化;浮游动物是浮游植物和鱼类等经济水生动物之间重要的营养通道,过分追求保护浮游动物是值得思考和研究的问题.而非经典生物操纵的核心内容是利用鱼类直接控制蓝藻水华;当鲢、鳙鱼达到阈值密度可以控制蓝藻水华,但很难控制所有藻类和降低N、P治理湖泊富营养化.在局部水体治理湖泊富营养化的对策是:把鱼类控藻、水生植被恢复和局部水域生态系统重建相结合,形成具有利用与控制蓝藻生产鱼类、吸收氮磷净化水质功能的"水质生物调控单元". 相似文献
7.
浅水湖泊湖沼学与太湖富营养化控制研究 总被引：2，自引：1，他引：1
自2007年无锡暴发饮用水危机事件以来,太湖经历了前所未有的高强度、大规模治理,各种治理措施累计投资已经超过千亿元.监测显示,在治理初期太湖的氮、磷浓度下降明显,水质有所好转,但最近几年关键水质指标总磷与浮游植物叶绿素α浓度出现了波动,蓝藻水华有所反弹.研究表明,太湖的外源负荷并没有减少,这与城镇用水量增加、污水排放标准偏低、面源污染削减不足有很大的关系;同时,内源负荷也因为蓝藻水华的持续而加重,浅水湖泊水深浅、扰动强的特点强化了磷的循环利用效率,加剧了内源负荷对湖泊富营养化和蓝藻水华的影响.气候变暖叠加营养盐富集的复合效应、流域风速下降以及暴雨事件频次和强度增加等气象水文条件变化,都促进了太湖蓝藻水华的暴发;蓝藻水华的时空分布特征则受湖泊水动力的决定性影响.太湖治理的曲折过程,凸显了大型浅水湖泊湖沼学研究的不断深入与发展,未来需要继续加强多学科交叉研究,特别是基于湖泊-流域系统的气象水文、生物地球化学和生物生态学的学科交叉.对于太湖生态环境的综合治理和管理,既要注重湖泊与流域相结合,更需要重视自然科学和人文科学的有机融合,才能真正达到控制太湖富营养化、维护流域水环境安全与社会经济可持续发展的目标. 相似文献
8.
富营养化浅水湖泊沉水水生植被的衰退与恢复 总被引：37，自引：4，他引：37
对国外近年来有关富营养化浅水湖泊的退化与恢复方面的研究进展以及生物操纵作用作了述评，对有关富营养化湖泊沉水植被衰退的有代表性的３种假说也作了介绍。根据“八五”期间武汉东湖水生植被重建的研究工作和多年积累的湖泊水生植被调查资料，提出了长江中下游浅湖富营养化过程中沉水植被演替的模式。 相似文献
9.
水生植被恢复对城市景观水体磷浓度及沉积物磷形态的影响 总被引：2，自引：1，他引：1
以上海市两个水生植被恢复时间为5—10年的城市景观水体为研究对象,通过分析水体理化性质以及水和沉积物磷的含量和形态,研究水生植被恢复对富营养化水体修复的长期生态效应.结果表明,水生植被恢复能有效降低水体氮、磷浓度,对水体富营养化有明显的改善作用.在外源磷的污染源得到控制后,水体磷浓度会随着修复时间的增加而逐渐降低并相对稳定.沉积物磷形态以钙磷为主,随着水生植被恢复时间的增加,生物活性较强的可交换态磷、铝磷和铁磷的含量下降,而相对稳定的钙磷所占的比例增加.研究结果还表明,即使不进行底泥疏浚,长期的水生植被恢复也可以使城市河流沉积物中内源磷释放及水体磷浓度得到有效控制. 相似文献
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Sabine Hilt Elisabeth M. Gross Michael Hupfer Harald Morscheid Jens Mhlmann Arnulf Melzer Jens Poltz Stefan Sandrock Eva-Maria Scharf Susanne Schneider Klaus van de Weyer 《Limnologica》2006,36(3):155-171
One of the most serious problems caused by eutrophication of shallow lakes is the disappearance of submerged macrophytes and the switch to a turbid, phytoplankton-dominated state. The reduction of external nutrient loads often does not result in a change back to the macrophyte-dominated state because stabilising mechanisms that cause resilience may delay a response. Additional internal lake restoration measures may therefore be needed to decrease the concentration of total phosphorus and increase water clarity. The re-establishment of submerged macrophytes required for a long-term stability of clear water conditions, however, may still fail, or mass developments of tall-growing species may cause nuisance for recreational use. Both cases are often not taken into account when restoration measures are planned in Germany, and existing schemes to reduce eutrophication consider the topic inadequately. Here we develop a step-by-step guideline to assess the chances of submerged macrophyte re-establishment in shallow lakes. We reviewed and rated the existing literature and case studies with special regard on (1) the impact of different internal lake restoration methods on the development of submerged macrophytes, (2) methods for the assessment of natural re-establishment, (3) requirements and methods for artificial support of submerged macrophyte development and (4) management options of macrophyte species diversity and abundance in Germany. This guideline is intended to help lake managers aiming to restore shallow lakes in Germany to critically asses and predict the potential development of submerged vegetation, taking into account the complex factors and interrelations that determine their occurrence, abundance and diversity. 相似文献
13.
This paper is a review of research works concerning the nutrient transportation, transformation and exchange between water, sediment and biota in the lakes from the middle and lower reaches of the Yangtze River conducted in the context of project entitled "The Processes and Mechanism of Lake Eutrophication in Middle and Lower Reaches of Yangtze River". All the lakes from this area are shallow lakes. According to the typical lake site research, the lakes from the middle and lower reaches of Yangtze River have a higher baseline of nutrition in the history. Normally the trophic status of these lakes can be categorized into medium-trophic or eutrophic. Human activities have been enhanced during the last decades, which speed up the lake eutrophic process. Lake eutrophication control needs to reduce not only the external nutrient inputs from watershed but also the internal loading from the sediments. Investigations revealed that the lake sediments in this area are considerablly high in nutrition in which at most about 30% of phosphorus exists in the form of bio-available in the sediment. The surface sediment will exert great effects on the nutrient exchange between water-sediment interface via adsorption and release of nutrient. The nutrient release from the sediment in these shallow lakes is mainly in two ways, i.e. in the undisturbed condition the nutrient is released through diffusion created by the nutrient gradient from sediment to overlying water; whereas in disturbed condition, the nutrient release is determined by the hydrodynamic forcing intensity and the sediment resuspension. Metallic elements such as the iron, manganese and aluminium and the aerobic-anaerobic ambience will affect the release of nutrients. The disturbed release will increase the total nutrients in the water column significantly in the short period. At the beginning of sediment resuspension, the dissolved nutrient concentration will increase. This increase will be damped if the ferric oxide and aluminium are rich in sediment because of the adsorption and flocculation. This means that the lakes have capability of eliminating the nutrient loadings. Investigations for the lakes from middle and down stream of Yangtze River have suggested that most lakes have the self-cleaning capability. Dredging the control of the internal loading, therefore, is only applicable to the small lakes or undisturbed bays which normally are situated nearby the city or town and rich in organic materials in the sediment. In addition, the strong reduction condition and weak aeration of these lakes and bays make these small lakes and bays release much more bio-available nutrient and without much self-eliminating capability. Moreover, eutrophication induced algal bloom in these lakes will change the pH of water, which further induces the increase in the nutrient release. In turn, the increase in nutrient release promotes the growth of phytoplankton and results in severe algal bloom. For the heavily polluted water, research suggests that the biomass of bacteria and alkaline phosphatase activity will be higher corresponding to the higher concentration of nutrients, which accelerates the nutrient recycling between water, sediment and biota. Quick recycling of nutrient, in turn, promotes the production and biomass growth of microorganism and leads to more severe eutrophication. Further research work should focus on the nutrient transformation mechanism and the effects of microbial loop on the eutrophication. 相似文献
14.
15.
本文系统地回顾了美国佛罗里达州大型浅水湖--Apopka湖富营养化和生态恢复的过程.流域水文状况的改变,围湖种植和向湖排放农业污水是Apopka湖从"草清型"转变为"藻浊型"湖泊的根本原因.50多年来,尽管内源控制的手段几经改变,但是,控制外源营养输入一直是Apopka湖整治的主要措施之一.Apopka湖富营养化的研究主要包括Apopka湖原始状态分析,浮游植物区系,生长限制因子,初级生产力,沉积物的理化特征和再悬浮,碳、氮、磷蕴藏量和释放率,富营养化的古湖沼学证据,外源磷负荷和恢复指标等.目前,Apopka湖生态恢复主要采取降低外源磷输入,通过人工湿地清除湖中悬浮物和颗粒磷,捕鱼除磷和生物操纵,种植水生植物和提高水位变动幅度等措施.最后介绍了围绕Apopka湖的富营养化及其恢复的学术争论.最后,还讨论了该湖研究和整治一些可能的存在问题和建议. 相似文献
16.
云南杞麓湖沉积物记录的近现代生态环境变化及影响因子识别 总被引：1，自引：0，他引：1
随着云南社会经济的持续发展与极端气候事件的频发,高原大中型湖泊面临着水质恶化、生态与环境功能退化的长期胁迫.为识别亚热带大型湖泊面临的主要环境压力,以杞麓湖为研究对象,在对沉积物钻孔进行物理(粒度、烧失量)、生物(色素、硅藻)等指标分析的基础上,结合现代监测和湖泊调查数据,重建了近两百年来湖泊水文条件、富营养化和环境变化的历史,并对硅藻群落结构的演化进行了驱动过程识别.沉积物粒度在1958年之前变化总体较为稳定且有较高的黏土含量;随着围湖造田等流域开发的增强,沉积物粒度组成自1960s开始频繁波动且粗颗粒组分快速增加.1981—2000年期间,随着落水洞泄水工程的修建杞麓湖的水位控制与水文调控得到加强,沉积物砂质含量降低且粒度组成变化较小;2000—2013年期间,湖泊疏浚工程的开展和区域降水的持续减少都导致了沉积物粒度组成波动较大、粗颗粒组成较高.沉积物色素记录了湖泊初级生产力的缓慢上升出现于19世纪中后期,并自1960s开始总叶绿素与蓝藻色素含量总体出现了较大幅度的增加趋势并持续至今.而在2000—2005年期间,湖泊浅水区的疏浚清淤导致了内源营养盐输入量的降低与藻类生物量的明显下降;沉积物蓝藻色素含量在1998、2008和2012—2013年左右出现明显的峰值,指示杞麓湖可能出现了较大范围的蓝藻暴发事件.统计分析结果显示,湖泊硅藻群落结构出现了多次明显转变且呈现底栖硅藻百分比长期降低的特征,水体富营养化的持续是驱动硅藻群落结构演替的主要因子,而水生植物退化、水文条件与气候变化也对硅藻群落的构建产生了重要的叠加影响.本文的沉积物分析结果表明,亚热带大型湖泊的生态治理与环境保护需要重点围绕营养盐负荷控制、水文调控优化与底栖生境恢复,并需应对全球变暖与极端气候事件产生的叠加影响. 相似文献
17.
水生高等植物-浮游植物关系和湖泊营养状态 总被引：29，自引：5，他引：24
本文根据中国一些湖泊的资料,从湖泊营养化角度分析了水生高等植物的生物量,分布和优势种以及浮游植物,透明度和湖泊营养状态的关系,表明高等植物和浮游藻类这两种初级生产者的生产在浅水湖泊中呈负相关,并反映在水质指标和湖泊营养状态下,同是,简要讨论了光限制,营养供给和生化抑制作用在浮游植物与水生高等植物关系中的作用。 相似文献
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