共查询到19条相似文献，搜索用时 140 毫秒
1.
有机质对城市污染河道沉积物铵态氮吸附-解吸的影响 总被引：2，自引：0，他引：2
采集污染程度不同的城市河道沉积物(通吕运河、濠河和通甲河),在分析H2O2对沉积物有机质和铵态氮影响的基础上,分析沉积物在去除有机质前后铵态氮释放动力学和吸附热力学过程,研究城市污染河道沉积物有机质对铵态氮吸附-解吸的影响.结果表明:单位体积H2O2对有机质去除率随H2O2使用量增多而降低;去除有机质后,沉积物铵态氮含量显著增加,通吕运河、濠河和通甲河铵态氮最大含量分别是有机质去除前的4.16、3.55和2.85倍;沉积物对铵态氮的饱和吸附量随有机质含量减少而下降;沉积物铵态氮释放过程均表现为先快速释放,后减缓至平衡过程;去除有机质后,随着有机质含量的减少,沉积物铵态氮的最大释放量呈增大趋势;沉积物有机质和铵态氮含量是影响沉积物铵态氮释放的主要因素. 相似文献
2.
过氧化钙在处理厌氧底泥中的应用初探 总被引：1，自引：0，他引：1
为改善河道厌氧底质及内源氮、磷等营养盐释放问题,考察对沉水植被恢复的影响,研发可同步解决沉积物供氧和削减内源氮、磷释放的氧缓释材料.实验通过向沉积物-水界面处散点注射不同剂量的过氧化钙(Ca O2),研究界面处溶解氧的动态变化特征及表层沉积物与底层水体之间溶解态氮、磷的交换过程.结果表明:添加Ca O2显著提高了界面处底层上覆水溶解氧浓度,随着Ca O2浓度的增加溶解氧浓度增加,不同处理组之间具有显著差异;Ca O2对沉积物中PO3-4-P释放具有明显的抑制作用,且随Ca O2浓度的增加抑制效果愈加明显,上覆水中可溶性活性磷浓度最大可削减98%.实验开始时,磷释放速率可降至-241.916±22.501 mg/(m2·d),降幅最高可达到144%;Ca O2对沉积物NH+4-N释放的抑制效果不佳,上覆水中NH+4-N浓度随着时间的变化波动性较大,且有逐渐增大的趋势.另外,添加Ca O2会显著提高底层上覆水p H值,不同处理组之间差异显著,但当Ca O2投加量小于0.529 kg/m2时,不会对苦草种子的萌发生长有显著影响,p H值波动在可接受范围内(7.62~10.87).因此,结合污染沉积物的状况,适当地投加Ca O2有望同步解决底质厌氧、内源磷释放及后期沉水植被定植底质生境改善的问题,可推荐为一种黑臭污染底泥治理技术在实际的河道生态工程中应用,其适宜浓度为0.176 kg/m2左右. 相似文献
3.
富营养化湖泊沉积物有机质矿化过程中碳、氮、磷的迁移特征 总被引：7，自引：2，他引：5
采用室内培养的方法,以富营养化湖泊太湖为例,研究了沉积物有机质矿化过程中碳、氮、磷的迁移特征.结果表明,在沉积物中的有机质矿化过程中,碳以溶解性无机碳释放至水中,同时以CH4和CO2形式释放至大气中,培养结束时,CH4和CO2累积排放含量分别为1492.21和498.96 mg/g(dw),其中CH4占气态碳的89.16%(以C质量计);此外,大量的氮、磷营养盐释放至上覆水体,水中总氮、总磷和铵态氮的最高浓度分别是初始浓度的62.16、28.16和139.45倍,而硝态氮浓度在整个培养过程中逐渐下降,培养末期浓度是初期的0.21倍;厌氧条件下,沉积物有机质的矿化,不仅可以生成大量的CH4、CO2气体,还能够促使沉积物中铵态氮和磷的释放;而沉积物有机质矿化释放的碳、氮、磷营养元素又能加剧湖泊富营养化程度,促进湖泊水体的初级生产力,从而增加湖泊沉积物有机质输入.这样的循环方式可能是湖泊富营养化自维持的重要机制之一. 相似文献
4.
水草腐烂引发的黑臭水体应急处置技术研究 总被引：3，自引：0，他引：3
水草腐烂加速水体耗氧和水体还原性物质的溶出进程,在夏、秋季高温条件下极易引发局部水体黑臭.以太湖沉水植物优势种马来眼子菜(Potamogeton malaianus)、苦草(Vallisneria natans)及浮叶植物优势种莕菜(Nymphoides peltatum)为受试材料,利用太湖原位底泥培养模拟水草腐烂形成的黑臭水体,考察不同的环境材料处置方式(壳聚糖(CTS)、聚合氯化铝(PAC)、聚丙烯酰胺(PAM)、CTS+PAC和PAC+PAM)对黑臭水体浊度、溶解氧浓度、挥发性硫化物等黑臭水体特征污染物的絮凝沉降规律及去除机理.结果表明:(1)絮凝处理24 h后,CTS+PAC组合对黑臭水体的浊度去除效果最佳,浊度去除率达70.3%,上覆水溶解氧浓度明显提高,增加率为261.5%;(2)加石英砂悬浊液加速絮体沉淀,形成絮体之后加石英砂使水体浊度稳步下降,4 h之后,浊度去除率达74.9%,显著高于与絮凝剂一起加入的处理组(29.8%);(3)植物腐烂释放的含硫特征嗅味物质主要为硫化氢(H_2S)、甲硫醚和二甲基三硫醚.不同植物体腐烂释放的含硫挥发性有机物浓度差异显著,马来眼子菜释放的4种含硫有机物总和分别为莕菜和苦草释放的319.8%和252.2%;(4)CTS+PAC处理后苦草及马来眼子菜腐烂水体中挥发性有机硫化物浓度较对照组分别降低了18.6%和44.5%.PAC+PAM组合絮凝处理组对莕菜腐烂水体中H2S有较好的去除效果,去除率达到52.4%.CTS+PAC絮凝剂组合处理的H2S浓度均低于对照组,苦草、马来眼子菜和莕菜腐烂后黑臭水体中H2S浓度分别降低了27.4%、41.0%和28.6%.CTS+PAC组合对H2S和二甲基硫醚类物质等致臭物释放的抑制效果优于PAC+PAM组合絮凝处理. 相似文献
5.
我国南方地区桉树种植区周边水库冬季水体泛黑现象频发,桉树砍伐残体(尤其是叶)浸出液中富含的溶解性有机碳(DOC)、单宁酸与铁、锰、硫化物等一系列反应是其主要致黑原因,然而目前致黑物质对水库泛黑的贡献程度和途径仍不清楚.为了模拟桉树叶浸泡对水库黑水形成的影响机制,研究选取夏季水体未泛黑期(水体热分层稳定)进行室内浸泡实验,测定每6 h上覆水体溶解氧(DO)、氧化还原电位(Eh)、透光度等理化指标,分析DGT有效态铁、锰、硫和DOC、单宁酸浓度分布规律及迁移转化特征,计算沉积物-水界面处Fe2+、Mn2+、S2-表观扩散通量.结果表明:桉树叶浸泡明显消耗水体中的DO,且显著影响水体Eh与透光度.此外,透光度与DO浓度呈显著正相关(相关系数为0.618~0.978).桉树叶浸泡释放大量DOC和单宁酸,其中单宁酸浓度远超有氧马尾松组,其上覆水中浓度分别达到23.9、26.0和34.0 mg/L,说明桉树浸泡为黑水形成提供了重要的DOC和单宁酸来源.桉树叶浸泡后上覆水和表层沉积物中DGT有效态Fe浓度均明显增加,深层沉积物间隙水中DGT有效态Fe浓度明显下降,且其表观扩散通量均为正值,说明深层沉积物中Fe向沉积物-水界面迁移,为黑水形成提供了重要的Fe来源.研究结果可为解决我国南方地区桉树人工林区水库水体突发性泛黑问题提供科学依据. 相似文献
6.
为了解东平湖菹草(Potamogeton crispus)腐烂分解对水体温室气体溶存浓度和界面扩散通量的影响,于2016年5-7月在东平湖菹草腐烂期采集上覆水和沉积物柱样,测定上覆水和孔隙水中温室气体(N_2O、CH_4和CO_2)的溶存浓度,采用Fick第一定律和双层模型计算沉积物-水-气界面扩散通量,同时分析上覆水和沉积物的理化性质,并采用网袋分解法于现场进行菹草腐烂分解试验,以探究东平湖菹草腐烂过程中温室气体溶存和扩散的主要影响因子及其主要来源.结果表明,菹草腐烂符合二次指数模型,分为快速衰减和慢速分解两个阶段;菹草腐烂过程中上覆水pH和亚硝态氮浓度表现为先降低后升高,而溶解氧、氨氮、硝态氮和可溶性正磷酸盐浓度则为先升高后下降,沉积物中铵态氮含量表现为先升高后降低,硝态氮为先降低后显著升高,有机质和p H呈降低-升高-降低的波动变化;上覆水中各温室气体浓度和水气界面扩散通量均表现为CO_2 CH_4 N_2O,其扩散通量分别为5862.9±5441.4、31.15±41.3和0.15±0.57μmol/(m~2·h),整体表现为大气温室气体的"源",并以碳排放为主;上覆水中N_2O浓度和水-气界面扩散通量均先降低后升高,孔隙水中N_2O浓度在快速和慢速分解阶段分别出现极大值(22.7和55.6 nmol/L),而其沉积物-水界面通量前期持续增加至腐烂结束后迅速降低;上覆水和孔隙水中CH_4浓度及其各界面通量均表现为前期略有降低后持续升高;上覆水中CO_2浓度和水-气界面通量表现为持续升高后降低并趋于稳定,而孔隙水中CO_2呈波动变化,在菹草腐烂初期向孔隙水扩散,后期向上覆水扩散.水温是影响上覆水中温室气体浓度和水-气界面通量的主要因素;沉积物是水体N_2O和CH_4的主要来源,孔隙水中浓度是控制其沉积物-水界面扩散的重要因素;而上覆水中CO_2呈现多源性,但以上覆水中有机物质的矿化为主. 相似文献
7.
浅水湖泊湖泛(黑水团)中的微生物生态学研究进展 总被引：5，自引：5，他引：0
"湖泛"是指湖泊水体中(包括沉积物)富含大量藻源性(或草源性)的生物质,在微生物的分解作用下,大量消耗氧气,出现厌氧分解,微生物在还原条件下,促进许多"黑臭"物质的形成,进而影响水质和湖泊生态系统结构与功能乃至造成环境灾难.与湖泛发生时的环境特征(如低溶解氧,低p H,高有机质,高总磷、总氮)相对应的是其简化的食物网结构和特殊的微生物类群.本文将主要针对湖泛中的微生物群落及其在物质循环中的作用展开综述.研究显示湖泛水体中主要微生物类群,如真菌、细菌厚壁菌门的梭菌以及产甲烷古菌等,在有机质的快速分解和厌氧矿化过程中发挥着重要作用;沉积物中主要的微生物功能群,如硫酸盐还原细菌、铁还原细菌、甲烷厌氧氧化菌和反硝化细菌等,是湖泛致黑物质形成的关键.缺氧及厌氧条件下碳、硫和铁等元素生物地球化学过程的相互关联以及多种微生物之间形成的互营共生可能是湖泛过程中功能微生物的重要特征.湖泛中微生物功能的进一步研究,亟需借鉴海洋低氧区及深海沉积物的经验,引用先进研究手段,提出可靠的生物地球化学证据.浅水湖泊湖泛(黑水团)中的微生物生态学探索将有助于从机理上揭示湖泛黑臭的成因. 相似文献
8.
正全国295座城市逾七成存在黑臭水体问题,这个现实令人痛心。河道有机污染普遍存在且日益突出,城市污水直排河道,流经城镇河段污染严重,水体出现季节性或终年黑臭,这些水环境问题亟需解决。那么,黑臭水体怎么界定?哪些手段可以治理?治理过程中还存在什么问题?带着这些,《地球》记者近日采访了清华大学环境学院环境生物学教研所胡洪营教授。 相似文献
9.
东洞庭湖沉积物覆水后磷形态变化及其释放量 总被引：4，自引：1，他引：3
研究干燥覆水后低流速条件下东洞庭湖沉积物中磷的形态变化及释放量,可以为轻度富营养化湖泊中磷的生物地球化学循环提供基础数据,为季节性湖泊內源营养盐的迁移转化规律研究、內源营养盐的释放风险评价提供理论依据.本文采集处于干湿交替状态的东洞庭湖表层沉积物,利用室内模拟装置,研究风干沉积物低流速条件下覆水后沉积物及上覆水中磷的形态变化.结果表明,低流速覆水后东洞庭湖沉积物中的磷向上覆水及大气中迁移释放,上覆水中磷的释放量随覆水时长增大,释放速率随覆水时长减小,上覆水流速和磷释放量相关性显著.上覆水循环过程中释放到上覆水中的溶解态有机磷比溶解态活性磷更容易吸附于颗粒物而转化为颗粒态磷.覆水后沉积物中各形态有机磷、无机磷及磷的生物有效性均发生转变,覆水初期沉积物中无机磷向有机磷转化,磷的生物可利用性增大;上覆水循环过程中有机磷向无机磷转化,磷的生物可利用性减小;覆水后沉积物的无机磷的主要组分由铝磷转变为铁磷,有机磷的主要组分有从中活性有机磷向活性有机磷转变的趋势. 相似文献
10.
水生植物是湖泊生态系统的重要组成部分,沉积物-水界面是湖泊生态系统中营养盐循环的重要界面,因而研究水生植物对沉积物-水界面微观剖面的影响具有重要意义.本文利用轮叶黑藻作为研究对象,研究了来自于香溪河、太湖和东湖3个样点的沉积物及上覆水中N、P等理化性质,并利用微电极研究轮叶黑藻对3种沉积物-水界面微观剖面是否有影响.实验结果表明:轮叶黑藻生长迅速.增长率因沉积物不同而不同,有一定的耐污能力;轮叶黑藻使水体和沉积物中总氮、总磷含量减少,对水体和底泥有一定的净化作用;轮叶黑藻可使水体溶解氧升高,并使沉积物有氧层厚度增加,改变沉积物的氧化还原电位;轮叶黑藻可能改变了根际微环境中微生物的数量和种类,而使沉积物和上覆水中的pH、N2O和H2S等发生变化. 相似文献
11.
研究湿地底泥污染特性及水-土界面边界层性质是明确大型人工湿地长期运行下底泥内源污染问题的关键.本文以典型人工湿地为例，通过综合布点垂向分层监测湿地底泥理化性质，明确底泥污染特性，分析水-土界面边界氧化层现象、性质及形成机理，探讨其性质成因.结果表明：与湖泊类似，长期运行人工湿地底泥也会产生氧化层，垂向由上到下分为氧化层、污染层、过渡层和健康层；运行6年的湿地底泥可形成厚约1 cm、无明显臭味、棕黄色可塑状的氧化层；与污染层相比，氧化层色味变淡、流动性减弱，含水率、d（0.9）、亚铁、总有机碳和总氮含量分别降低7.20%、54.04%、54.59%、17.89%和7.00%，氧化还原电位和总磷含量分别升高150.41%和18.17%；氧化层是由氧化、沉降协同作用下形成的底泥表层氧化态微环境，其中上覆水溶解氧水平越高越有利于提高氧化层致密程度，降低氧化层有机质、总氮含量，上覆水悬浮物浓度越高、水深越深越有利于增加氧化层厚度. 相似文献
12.
蓝藻水华暴发形成的大量有机碎屑，沉降到沉积物表面，影响沉积物有机质矿化，进而影响碳氮磷循环.本实验选择于桥水库湖心区作为沉积物采样点，通过设置不同密度藻屑添加组（×1倍组和×20倍组）及空白对照组，研究藻屑堆积对沉积物矿化特征的影响及其环境效应，为蓝藻水华影响下的饮用水环境修复和科学管理提供一定的理论依据.结果表明：（1）藻屑添加降低了上覆水pH值，改变了沉积物生物酶活性.藻屑添加密度越大，上覆水pH值越低、波动越大，反映了培养过程异养微生物活性的变化.×1倍组的转化酶活性较高；×20倍组蛋白酶活性和碱性磷酸酶活性较高.（2）藻屑添加对沉积物的矿化途径和沉积物产物的释放速率产生了显著影响.藻屑添加密度越大，有机质矿化速率越大.其中，×1倍组主要增强好氧矿化，释放CO2；×20倍组主要增强厌氧产甲烷矿化，释放CH4.（3）不同密度的藻屑添加组，其氮磷扩散、释放通量存在明显差别.×1倍组以沉积物吸附为主，其上覆水NH4+和PO43-平均释放速率与对照组差异较小；×20倍组的NH4+在第0~10天以沉积物吸附为主，之后和PO43-均以向上覆水中释放为主，其NH4+和PO43-平均释放速率（分别为0.223）和0.075 mg/（L·d））明显大于其他实验组.因此，大量蓝藻堆积明显促进沉积物的碳氮磷矿化，释放大量CO2、CH4和氮磷营养盐至上覆水中，对湖泊水环境造成污染，为蓝藻的生长繁殖作贡献. 相似文献
13.
The chemical composition of riverine suspended sediment is the integration of the weathering crust minerals, soil organic matter and erosion agency within a specific drainage basin, which has been largely disturbed by the human activities. Selected metal elements of the riverine suspended sediment in the Zhujiang River were analysed using inductively coupled plasma–atomic emission spectrometry (ICP–AES) in three different hydrological phases from 1997 to 1998 at Makou and Sanshui hydrographic gauge stations, located at the lower reaches of the two main tributaries of the Zhujiang River, i.e. the Xijiang and the Beijing Rivers respectively. Organic carbon and nitrogen were also analysed using a conventional element analyser. The results demonstrate that the chemical composition of the riverine suspended sediment show obvious variability in different hydrological phases, which closely correlate to the organic matter content in suspended sediment. Intensified erosion in the flood phase results in lower concentration of the organic matter than that in the lower water level phase. The riverine suspended sediment with rich organic matter in the lower water level phase adsorbs some metal elements from the river water. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
14.
We studied the dynamics of bacteria and organic matter in the Ancient Port of Genoa (Italy) during a bioremediation treatment of sediment (during summer-autumn 1998) in an area characterised by continuous sewage discharge. A strong increase in total benthic bacterial density (TBN) was recorded at the end of the study, from 14 x 10(8) to 58-172 x 10(8) cell g(-1) in different parts of the treated area. The TBN increase was linked to organic matter depletion, from more than 40 to less than 20 mg x g(-1). In order to highlight the main ecological mechanisms involved in bioremediation, a laboratory experiment based on both water and sediment from the basin studied was carried out. We observed an increase in TBN during the first 20 days and a decrease in sediment organic matter (up to about 20%). Increases of organic matter (about 2-fold) and TBN (from 21 to 33 x 10(9) cell l(-1)) occurred in the overlying water, suggesting a strong association between the sediments and water column processes. Hydrolytic activities, which double in the sediment and increase up to a 300-fold in the water, are consistent with the decrease in sediment organic matter and with the water fraction dynamics. 相似文献
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Paraskevi N. Polymenakou Glykeria Fragkioudaki Anastasios Tselepides 《Continental Shelf Research》2007
Recently, black carbon has been introduced as the form of carbon that may be separated from the biologically mediated carbon cycle thereby representing the non-bioavailable fraction of the estimated organic carbon. It has been speculated that the bioavailability of organic matter may be a limiting factor for the presence of active bacteria within the sediments. In order to address this question, marine sediments were collected from the Thracian Sea (Eastern Mediterranean), a complex system impacted by riverine inputs and Black Sea water masses. In addition to counts of total bacteria, we estimated the fraction of active bacteria by using a destaining step to the DAPI staining method. Black carbon was also estimated following the thermal oxidation method in order to determine the fraction of the refractory organic matter. The fraction of black carbon to total organic carbon varied from 16% to 53% indicating that black carbon constitutes a significant pool of sedimentary organic carbon in the Thracian sea. A fraction ranging from 18% to 97% was scored as nucleoid containing cells. We did not record any significant differences in the fraction of nucleoid-containing bacteria among sediment depths (P<0.05) indicating that there was no accumulation of dead bacterial cells with depth. The same was observed for the fraction of black carbon and bioavailable organic carbon with sediment depth (P<0.05) indicating that benthic consumers are not the key regulators of the organic matter pool in these sediments but have a minor effect. A possible reason for these observations and for the uncoupling between the active bacterial fraction and the bioavailability of organic matter could be (i) the presence of refractory components in the estimated bioavailable organic matter and (ii) the hydrological and geological complexity of the study area. The North Aegean marginal slopes are highly unstable experiencing frequent seismic events. These events are capable of inducing sediment transport from the upper slopes thus altering the entire sediment profile. On the other hand, the significant correlations that were recorded between nucleoid-containing cells and phytopigments (chlorophyll a, phaeopigments, chloroplastic pigment equivalents) at all sediment depths indicate that bacterial communities respond immediately to the deposited phytodetritus, using it as a primary source of carbon and energy. Our data suggests that the Thracian Sea sediments are by no means homogeneous and can best be described as a mosaic controlled by numerous local and regional environmental factors. 相似文献
16.
以福建泉州水源地山美水库和惠女水库的表层底泥和上覆水为研究对象,室内静态模拟试验研究了生物沸石薄层覆盖削减水源水库氮负荷的效果及可行性,探讨了上覆水体溶解氧(DO)浓度对削减氮负荷的影响,分析了削减氮负荷的作用机理.结果表明,覆盖强度为1 kg/m~2的生物沸石覆盖(厚度约1 mm)对上覆水中总氮的削减率为58.89%~65.75%,对底泥中总氮的削减率为10.39%~13.08%,对底泥中铵态氮的削减率为32.35%~44.56%,对底泥中有机氮的削减率为8.41%~11.04%;对于以硝态氮为主要形态氮的上覆水体,DO浓度越低,越有利于高效菌脱氮;可见,生物沸石薄层覆盖能有效削减水源水库氮负荷,利用生物沸石薄层覆盖技术削减水源水库氮负荷是可行的,但需要进一步研究水源水库底泥生物沸石薄层覆盖修复过程中氮的迁移转化机制. 相似文献
17.
波浪水槽中研究了小波掀沙(波高8.77cm,波周期0.8s)和大波掀沙(波高12.31cm和13.29cm,波周期1.0s)对太湖沉积物悬浮及N、P营养盐释放的作用规律.结果显示:小波掀沙时,底泥并未发生大量悬浮,SS浓度最高时仅13.6mg/L;大波掀沙时,底泥大规模悬浮,SS浓度最高达达245.2mg/L水体悬浮物、营养盐浓度变化滞后波高变化1h以上.当波高改变1h后,水体悬浮物、N、P营养盐浓度才改变到相应的平衡浓度.除总磷浓度显著提高外,小波掀沙对水体N、P浓度的影响很小,大波掀沙则显著提高了水体总氮、总溶解氮、总磷、总溶解磷、氨氮(NH4 -N)、溶解性活性磷(SRP),其中NH4 -N、SRP最大增幅达30％和20％.小波和大波掀沙过程中,水体溶解氧浓度均持续增加,掀沙2h后增高2mg/L,溶解性有机碳持续下降,2h后下降33％-51％.试验结果表明,掀沙过程中水体充氧及颗粒物的絮凝、吸附作用可能是限制NH4 -N、SRP浓度增高的重要因素之一. 相似文献
18.
The origin and the chemical and isotopic evolution of dissolved inorganic carbon (DIC) in groundwater of the Okavango Delta in semi-arid Botswana were investigated using DIC and major ion concentrations and stable oxygen, hydrogen and carbon isotopes (δD, δ18O and δ13CDIC). The δD and δ18O indicated that groundwater was recharged by evaporated river water and unevaporated rain. The river water and shallow (<10 m) groundwater are Ca–Na–HCO3 type and the deep (≥10 m) groundwater is Na–K–HCO3 to HCO3–Cl–SO4 to Cl–SO4–HCO3. Compared to river water, the mean DIC concentrations were 2 times higher in shallow groundwater, 7 times higher in deep groundwater and 24 times higher in island groundwater. The δ13CDIC indicate that DIC production in groundwater is from organic matter oxidation and in island groundwater from organic matter oxidation and dissolution of sodium carbonate salts. The ionic and isotopic evolution of the groundwater relative to evaporated river water indicates two independent pools of DIC. 相似文献
19.
Different morphology of Nuphar lutea in two contrasting aquatic environments and its effect on ecosystem engineering 
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下载免费PDF全文 Jonas Schoelynck Kris Bal Veerle Verschoren Ellis Penning Eric Struyf Tjeerd Bouma Dieter Meire Patrick Meire Stijn Temmerman 《地球表面变化过程与地形》2014,39(15):2100-2108
Aquatic plants (macrophytes) can have a large effect on river hydraulics and geomorphology. Though, the extent to how plant morphological plasticity actively influences these feedbacks has received little scientific attention. The nymphaeid macrophyte species Nuphar lutea (L.) Smith is characterized by a distinct leaf duality. Floating leaves shade most of the submerged leaves thereby limiting light penetration in the water. Despite their apparent negligible photosynthetic role, submerged leaves of N. lutea remain intact during summer and contribute a significant part to the total biomass. Our results indicate that the submerged leaves are crucial in plant–flow interactions and hence in the engineering potential of the plant, i.e. the capacity to locally reduce flow velocities and to promote sedimentation, including organic matter deposition. Plant individuals growing in running river water were compared to individuals from adjacent oxbow lake water. The number and size of submerged leaves were significantly higher for river standing individuals and the accumulated sediment contained significantly more organic matter, total nitrogen and total phosphorus, and was characterized by a lower carbon/nitrogen ratio and a finer grain size. We therefore argue that the submerged N. lutea canopy in rivers has the ability to create a high‐nutrient, low hydrodynamic environment, resembling the conditions found in oxbow lakes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献