沉水植物菹草对富营养化水体中TN生态效应及模型研究

通过室内模拟构建水体营养盐和菹草生物量正交试验,研究菹草从石芽萌发至菹草植株衰亡腐烂整个生命周期中,对水体中TN的生态效应,并以此为依据建立菹草对富营养化水体生态效应模型。研究表明:在不同生物量菹草作用下,富营养化水体中TN含量是先下降后上升的一个周期式过程;在相同营养水平条件下,菹草对TN的吸收量随菹草生物量的增大而依次递增,而在相同生物量的前提下,菹草对TN的修复力存在一个最佳营养水平范围,即13.95—20.56 mg·L~(–1)之间;菹草对富营养化水体生态效应模型分两部分:菹草对富营养化水体中TN与时间关系模型以及菹草生态修复水体TN限度理论模型,通过这两个模型的构建可以为生产实践中菹草在生态修复富营养化水体的投放量和菹草的最佳收割时间提供有力依据,为工程实践提供有效保障。     

五种沉水植物对富营养化水体的净化效果

为达到净化水质的目的,采用移栽沉水植物控制富营养化水体中营养盐含量和浮游藻类生物量.本研究在夏季藻类密度较高的富营养化水体中移栽5种长江中下游流域常见沉水植物,比较不同沉水植物去除营养盐和控制藻类总量的能力.研究结果:5种沉水植物对水体总氮含量去除率的大小顺序为:竹叶眼子菜＞黑藻＞苦草＞微齿眼子菜＞菹草,对总磷去除率大小顺序为:竹叶眼子菜＞黑藻＞微齿眼子菜＞苦草＞菹草;竹叶眼子菜控制水体中藻类总量的效果最佳,苦草、微齿眼子菜及菹草次之,黑藻对水体总磷和浮游植物的去除效果均极显著(p≤0.01),而对总氮含量的作用影响不明显(p=0.209).综合营养盐吸收作用和藻类控制效果来看,竹叶眼子菜在整个实验过程中生长状态良好并达到较为稳定的净化作用,是夏季治理浅型富营养化静水水体的理想物种之一.     

香根草对土壤中几种重金属离子富集能力的比较研究

用组织培养的香根草无菌苗作为试验材料,进行香根草对Cd、Cr、Pb和Ni四种重金属离子的富集能力比较试验,分别测定了香根草体内的重金属含量、香根草与重金属元素的相关性、香根草对重金属的富集系数和根系滞留率.结果表明：香根草对四种重金属离子都具有较高的富集能力.其中,香根草植物体中元素总含量表现为Ni＞Cr＞Pb＞Cd,在茎叶和根中的分含量,均表现为根＞茎叶;香根草与重金属元素的关系中,Cd的相关性最显著;富集系数与重金属浓度呈负相关,以Ni最为明显;从滞留率的角度来看,以Cr在香根草根系的滞留率最大,但对同一种重金属来说,随浓度的变化,香根草根系对它的滞留率却几乎是恒定的.     

中国野生的香根草种及其保护与分类问题

香根草（Ｖｅｔｉｖｅｒｉａｚｉｚａｎｉｏｉｄｅｓ）这一优良的水土保持和多用途植物目前在热带和亚热带地区广泛推广应用。中国的香根草栽培种主要是在５０年代从国外引进的,但在广东和海南也有这一植物的野生种存在,尤其在广东的吴川有一块面积达６６７０ｈｍ２左右的野生香根草群落。然而,由于人类活动的影响和过度开发利用,４０年间,这片热带草原已遭到严重破坏,面积和蕴藏量都大幅度减少。为了不使这片珍贵的湿地消失殆尽,必须尽快采取措施加以保护。另外,香根草属的系统分类还很不完善,上述在中国分布的野生居群究竟是香根草还是野香根草（Ｖ．ｎｉｇｒｉｔａｎａ）,迄今还没有定论,经对标本的研究鉴定,初步确定为香根草（Ｖｅｔｉｖｅｒｉａｚｉｚａｎｉｏｉｄｅｓ）。     

河岸美人蕉和香根草的生长繁育及其腐烂规律

以河岸带中的美人蕉、香根草为对象,研究了河岸带生态恢复过程中植物的生长及其作用。结果表明:美人蕉和香根草二者对水深的耐受性均不强,不适合在深水中生长与繁殖;与美人蕉相比,香根草对水深的耐受性更强;美人蕉不适合在水深>20cm的水域生长;美人蕉地上的生物量比地下高27.5%,香根草地上的生物量比地下高79%;通过收割美人蕉分别带走美人蕉所固定的全部氮、磷的59%和55%,收割香根草带走香根草所固定的全部氮和磷的57%;经过130d的浸泡,美人蕉、香根草质量损失率分别为31.89%和19.8%,全氮、全磷的损失美人蕉分别为49.43%和77.30%,香根草分别为47.54%和86.06%;植物浸泡释放有机物、氮和磷,但水中COD、NH4 -N和TP浓度并不持续增加。     

中国栽培的香根草是外来入侵种并会蔓延成为杂草吗?

1988年国际香根草网络主席里查德·格雷姆肖先生引入到中国的香根草技术是一种利用香根草进行水土保持、环境保护、生境恢复、防灾减灾、污染治理的生态工程与植物修复技术。在过去20多年,该技术应用到中国南方10多个省区,取得了显著的生态效益与社会效益。然而,当年引入香根草技术时,海南、广东、福建等地早已有"野生"的香根草存在,甚至可以追溯到1936年。而最初的香根草种源究竟是中国本土生长还是从国外引入?至今未见确凿的证据或资料。目前,世界上栽种的香根草是通过分蘖等无性繁殖的,在中国未发现香根草的无序蔓延及其"排他"现象。与此相反,由于香根草的种植可改善恶劣的生境条件,使其他乡土植物得以很快定居并生长,从而导致香根草自身萎缩甚至消失。此外,香根草对除草剂非常敏感,常因除草剂的喷洒而消失。因此,把香根草当作外来入侵种并认为会成为杂草的说法是缺少科学依据的。     

垃圾污水的植物毒性和植物净化效果之研究(英文)

广州李坑拉圾卫生填埋场的渗滤污水含有高浓度的污染物,经过人工净化后仍未达到排放标准,对植物产生毒害。在被观测的４种植物中,水葫芦（Ｅｉｃｈｈｏｒｎｉａｃｒａｓｉｐｅｓ）在高浓度和低浓度２种污水中均被毒害致死;百喜草（Ｐａｓｐａｌｕｍｎｏｔａｔｕｍ）在高浓度的渗滤液中不能存活,在低浓度中受严重伤害;水花生（Ａｌｔｅｒｎａｎｔｈｅｒａｐｈｉｌｏｘｅｒｏｉｄｅｓ）在高浓度污水中受较重伤害,但在低浓度形成庞大生物体,这可能是污水的“富营养化”所致;香根草（Ｖｅｔｉｖｅｒｉａｚｉｚａｎｉｏｉｄｅｓ）在这２种污水中亦受伤害,但受害程度为４种植物中最轻。在污水中表现相对较好的２种植物中,水花生对低浓度污水的净化效果总体上好于香根草,尤其对总氮和硝态氮的净化效果明显好于香根草,但香根草对高浓度污水中的７种“污物”的净化效果均优于水花生,且对低浓度污水中的磷与ＣＯＤ的净化亦优于水花生。在被观测的７种水质指标中,植物对氨态氮的净化效果最好,净化率在７７％～９１％之间。此外,香根草对磷也表现出了较强的净化能力,净化率高达７０％以上。香根草和水花生可分别作为高、低２种浓度垃圾污水的净化植物来辅助净化污水。     

香根草系统在我国的应用与发展20年历程回顾

香根草系统是一种价格低廉、用于水土保持、基础设施保护、污染控制和治理、减轻自然灾害等的有效系统,自1988年引入我国已历经20年。本文回顾了香根草系统在我国农业、边坡防护、环境保护方面的研究和应用情况,介绍了香根草网络的发展和作用,并提出香根草系统在不毛之地造林、矿山植被恢复、生物燃料和缓解温室效应等方面的应用潜力。     

长期水陆周期性变化条件下香根草形态性状和生物量分配的可塑性

香根草是能够长期适应三峡水库消落带生境的少数物种之一。虽然国内对香根草的引种栽培和研究已有几十年的历史，但是对香根草在三峡库区消落带长期水陆周期性变化条件下的生态适应对策还知之甚少。为此，以2008年在三峡水库巫山段消落带建立的香根草引种栽培试验示范基地为研究平台，在2016年对海拔166—169 m、169—172 m和172—175 m区段的香根草的形态性状、生物量及其分配特征进行了研究。结果表明：(1)海拔166—169 m香根草的分蘖株数、平均株高、节间数量、节间长度、叶片数/分蘖株、叶片数/丛、叶片长等各指标值均低于海拔169—172 m和海拔172—175 m,海拔166—169 m与其它海拔区段的节间数量差异显著(P<0.05);(2)海拔166—169 m香根草的根系数量最少，但根系长度最长；(3)海拔166—169 m无节间的香根草株数最多，且与海拔172—175 m和海拔169—172 m差异显著(P<0.05);(4)不同海拔区段香根草的总生物量大小表现为海拔172—175 m>海拔169—172 m>海拔166—169 m,且海拔166—...     

风车草和香根草在人工湿地中迁移养分能力的比较研究

为研究风车草(Cyperus alternifolius)和香根草(Vetiveria zizanioides)迁移养分的能力,建立17.0m²风车草潜流式人工湿地和13.3 m²香根草潜流式人工湿地处理猪场废水,在四个季节末测定植物生物量和组织氮、磷、铜、锌含量.结果表明,香根草地下部生物量大于风车草,地上部生物量则是风车草大于香根草.风车草年地上部收获量为3406.47 g·m^-2,比香根草的1483.88 g·m^-2高2.3倍;风车草的氮含量为22.69 mg·g^-1,比香根草的15.44 mg·g^-1高7.25 mg·g^-1;风车草的磷含量为6.09 mg·g^-1,比香根草的5.47 mg·g^-1高0.62 mg·g^-1.植株含铜、锌量风车草略比香根草高.风车草每年迁移N 68.72 g·m^-2和P18.49 g·m^-2,香根草迁移N 8.93 g·m^-2和P 3.69 g·m^-2.风车草人工湿地每年由植物迁移的氮、磷、铜、锌比香根草高4～7倍.     

4种水生植物对富营养化水体氮磷去除效果的研究

以灯心草、水田芥、菹草和轮藻为试验对象,研究了其在两种不同程度富营养化水体中的生长状况及对水体中总氮(TN)、总磷(TP)、氨氮(NH4+-N)和化学耗氧量(COD)的净化效果。结果表明,在轻度富营养化水体中水田芥效果最好,培养20 d后的水田芥对总氮、总磷、氨氮和化学耗氧量的吸收率分别为75.28%、93.00%、76.35%和83.74%,其它3种水生植物对水体也都有较好的净化效果;在重度富营养化水体中灯心草效果最好,培养20天后的灯心草对总氮、总磷、氨氮和化学耗氧量的吸收率分别为89.30%、83.11%、83.41%和78.56%,但水田芥和轮藻的净化效果相对较差。     

利用水生植物原位修复污染水体

在实验围隔系统中，夏季利用凤眼莲、冬季利用耐寒型沉水植物伊乐藻等恢复水生生态系统，研究水生植物对水体氮、磷营养盐、透明度等理化性质的影响.结果表明：水生植物处理围区营养盐水平均显著低于围区对照和大湖水体.最初15 d，凤眼莲生长速度快，覆盖面积从100 m²增加到470 m²；44 d后，覆盖面积达到65％，处理围区的水质最佳，总氮(TN)、铵态氮(NH₄⁺ -N)、亚硝态氮(NO₂^- -N)、高锰酸钾盐指数(COD_Mn)和叶绿素a浓度最低，透明度达到1.7～1.8 m(水底).10月份后，处理围区水体总磷(TP)维持在0.1 mg·L^-1左右.处理围区透明度提高后，伊乐藻逐渐成为优势种(覆盖面积达到总水域的1/3)，在净化水质、维持水质理化性质稳定和提高透明度方面作用显著.表明水生植被恢复可以有效降低水体营养盐，控制浮游植物增长，是改善富营养湖泊水质的重要措施.     

江西省余江县水体营养状况分析

用营养状态指数法(TSI)对江西省红壤区余江县东塘、五湖、仙塘三个水库的水质状况进行综合评价,结果表明三个水体的水质状况均呈富营养态。在此基础上对三个水库的10项主要水化学指标进行主成分分析,表明亚硝态氮和氨氮对第一主成分的贡献最大,COD为第二主成分的主要贡献者;而且三个水库的水质受水中有机物含量的影响最大,这一结果与当地的农业结构密切相关。     

水生植物对富营养水体水质净化作用研究

利用富营养浅水湖泊武汉东湖中所建立的大型实验围隔系统,对沉水植物的水质净化作用作了现场实验研究。重建后的沉水植物可以显著改善水质,水体透明度显著提高,水色降低。在研究期间,水生植物围隔CODcr和BOD5一般分别为20和5mg/L左右;对照围隔和大湖水体则分别约为40和10mg/L。水生植物围隔水体中检出的有机污染种类也较对照围和大湖水体柢。实验结果表明恢复以沉水植物为主的水生植被是改善营养湖泊水质和重建生态系统的有效措施。     

Study of the photodegradation of 2-chlorobenzoic acid by TiO2 and the effects of eutrophicated water on the reaction

The photodegradation of 2-chlorobenzoic acid (2-CBA) in suspensions of TiO₂ was examined under different operational parameters. The optimal condition could be obtained through the experiment, i.e. that the concentration of 2-CBA was 30 mg/L and the dosing quantity of TiO₂ was 0.01 g under UV light in the case of pH 3.5. Above reaction process was in accordance with first order kinetics model. The influence on photocatalytic degradation caused by typical anions in eutrophicated water body such as NO₃⁻ and H₂PO₄⁻ was explored in this work, which revealed that both two anions had inhibitory effect on the degradation process. In addition, alcohol was introduced into the process to identify the degradation mechanism of 2-CBA with TiO₂, and the reaction route of 2-CBA could be predicted through the analysis on the intermediate.     

富营养化水体的水生植物净化试验研究

利用水生植物净化和底泥遮蔽的方法对养鱼池的富营养化水体进行控制研究．结果表明,金鱼藻等6种水生植物对水中总氮、总磷和硝态氮有较好的去除效果,而以狐尾藻和微齿眼子菜两种效果最好,1个月后对总氮的去除率分别为83．84％和77．54％,对硝态氮的去除率分别为95．85％和90．65％,磷的去除率都达到了91．7％．但对氨氮的去除效果稍差,1个月时去除效果只有14％～70％．底泥进行塑料遮蔽处理后在前期(15～20d)能控制底泥中营养盐的释放,但不能保持长久;并在后期表现出“补偿效应”．试验结果还表明。水生植物能有效提高水体透明度和水体观感,但对改善COD和DO的效果不明显．     

Numerical study on amelioration of water quality in Lakes Shinji and Nakaumi: a coastal brackish lagoon system

Aiming at estimating the effect of an amelioration scheme for water quality in a highly eutrophicated and strongly enclosed estuary, especially placing emphasis on the alleviation of a oxygen-depleted water body, a three-dimensional (3-D) time-dependent coupled physical and ecological model was applied to Lakes Shinji and Nakaumi, a typical coastal brackish lagoon system in Japan. First, the model was run to reproduce the seasonal variation in water temperature, salinity, dissolved oxygen, and other ecological constituents during the period from April 1998 to March 1999. The daily change regimes of the observed sea surface winds, tidal elevation at the open boundary, river discharges, and meteorological parameters were incorporated into the forcing variables of the ecosystem model. Next, as a numerical experiment, a scenario simulation was carried out under four premises to alleviate the oxygen-depleted water body. The model results agreed fairly well with the field measurements obtained through the regular environmental monitoring in the lagoon system. It was found that an oxygen-depleted water body appears in the eastern part of Lake Nakaumi in early May and develops to cover the whole lagoon in midsummer to leave it almost anoxic. The scenario simulation revealed that each amelioration scheme has a considerable effect in alleviating this hypoxic water body. It was found from the model results and the additional flux analyses that the oxygen concentration will improve as a result of (1) change in the flow field by cutting the dikes built up during lake reclamation and (2) decrease in benthic oxygen consumption by filling up deep holes once created by dredging activities. An erratum to this article is available at .     

Restoration of Cirsio-Molinietum wet meadows by sod cutting

This study evaluates the prospects for restoration of the Cirsio-Molinietum orchietosum by sod cutting of an eutrophicated Cirsio-Molinietum stand and of a former agricultural grassland and an alder cart, respectively. Sod cutting of the former agricultural grassland and of the alder cart sufficed to restore this plant community, whereas sod cutting of the eutrophicated Cirsio-Molinietum was not successful. The unsuccessful restoration of the eutrophicated Cirsio-Molinietum might be due to prolonged inundation resulting from the sod cutting, causing anaerobic conditions under which no nitrification takes place. The chemical composition of the deep groundwater supplying the site changed from base-rich and SO₄²⁻-poor to base-rich and SO₄²⁻-rich. This change in chemical composition of the deep groundwater, discharging in the study area, might cause a higher nutrient availability in the root zone, and therefore, negatively influence the prospects for the restoration of the Cirsio-Molinietum. Furthermore, successful restoration of the Cirsio-Molinietum requires (1) water tables close to the soil surface during at least six months and (2) discharging base-rich groundwater in the root zone.     

Cellulose degradation in different types of limnic environments

The decrease in tensile strength of chemically untreated cotton threads that had been exposed at different levels in lake water and lake sediment was investigated. The quotient of the tensile strength before and after exposure was taken as a measure of the potential cellulolytic activity. Two oligotrophic Swedish lakes showed a very weak cellulolytic activity. In the eutrophicated Lake Trummen the activity was high in the summer specially at the sediment-water interface, but low in the winter. During the restoration of this lake by suctiondredging the nutrient-rich sediment up on land, an easily measureable activity could also be detected in the water. The cellulose degradation was also studied in some rivers and streams and in the water of three sewage treatment plants.

     

Volatile organic compound emissions from Microcystis aeruginosa under different phosphorus sources and concentrations

In eutrophicated water, cyanobacteria massively grow and release an abundance of volatile organic compounds (VOCs) that contribute to the water odor. To uncover the effects of different phosphorus (P) nutrients on the formation of cyanobacteria VOCs and water odor, the cell growth and VOC emissions of Microcystis aeruginosa were investigated under different P nutrient conditions. Among K₂HPO₄, Na₄P₂O₇, and (NaPO₃)₆, K₂HPO₄ showed the largest increase in cell density, while a reduction in P concentration decreased the cell density. There were 26, 23 and 22 compounds in M. aeruginosa VOCs with K₂HPO₄, Na₄P₂O₇ and (NaPO₃)₆ as the sole P source, respectively, including sulfocompounds, terpenoids, benzenes, hydrocarbons, alcohols, aldehydes, and esters. Non‐P markedly promoted the VOC emission, and six additional compounds were observed: α‐pinene, 1‐phenyl‐1‐butanone, 1H‐1‐ethylidene‐indene, 2,6,10‐trimethyl‐tetradecane, 2‐ethyl‐hexanal, and acetic acid 2‐ethylhexyl ester. It can be deduced that cyanobacteria release different VOC blends using various P forms in eutrophicated waters, and the reduction of P amount promotes VOC emission and increases the water odor.