太湖地区高效除氮浮萍品种的筛选及其除氮机理的初步研究

农业面源污染是引起太湖水体富营养化的重要因素,而植物生态工程技术在面源污染的治理中起到了很大的作用。本文调查和收集了太湖地区13个稻田浮萍种质资源,研究了不同浮萍品种对低浓度稻田排水中氮（N）素的去除效果及其初步除N机理。结果表明,在实验营养条件下,4种浮萍品种中紫背浮萍（Spirodela polyrrhiza）具有最高的N去除效率,其次是少根紫萍（Spirodela oligorrhiza）或稀脉浮萍（Lemna perpusilla）,而除N效果最低的品种是青萍（Lemna minor）。供试材料对水体中总N的去除率范围为57.3% ~ 85.2%,其中紫背浮萍HZ1具有最高的去除效果,15天后总N去除率可达到85%,青萍WX3去除效果最低,15天后去除率仅为57%。两个浮萍品种进行比较发现,HZ1生物量增长速度慢,鲜重和干重平均倍增时间分别为7.96天和7.82天,而WX3的鲜重和干重倍增时间分别为5.20天和4.73天。另一方面,HZ1和WX3的含N量分别为4.9% 和5.7%。由此可以推知,紫背浮萍HZ1高效除N的主要机理不是通过生物体吸收,而更可能是微生物或化学作用共同引起。     

漂浮栽培水生植物对入滇河流污水中磷的去除效果研究

利用水生植物净化富营养化水体是污染水体生物治理的途径之一,为了找出适宜在水体中生长并对磷的去除效果较好的植物,选择5个品种的水稻以及空心菜、茭白和水花生为供试水生植物,通过静态水培试验,研究了各植物在富营养化水体中的生长状况,以及对水体中磷的去除效果。结果表明,在不添加任何植物营养的条件下,植物在富营养化水体中均能正常生长;有植物处理系统对水体中总磷（TP）、水溶性总磷（DTP）的去除效果显著高于无植物对照;有植物处理系统TP的去除率为53.28%～84.07%,DTP的去除率为44.99%～88.81%;无植物对照TP的去除率为32.57%,DTP的去除率为37.51%。植物组织所累积的磷占各自系统去除量的21.54%～75.32%,植物的吸收作用是磷去除的主要途径。水稻功米1号的经济产量最高,为616.28 g.m-2,组织所累积的磷占系统去除量也是最大,为75.32%。在所有供试植物中,水稻功米1号对富营养化水体既有较好的净化效果,又能获得一定的经济产量,是最优的净化植物,同时也是最适宜在水体中生长的水稻品种。     

冬春季多年生牧草对富营养化水体的响应及净化效果研究

在室外条件下以8种多年生牧草为材料研究其在重度富营养化水体中的生长状况及生长期间对水体氮磷的削减。结果表明,8种牧草均能适应水生环境并快速生长。经过收割后,每1m2的坦克草浮床生长期内可从水体中吸收17.5g的氮和7.5g的磷。牧草修复水体后,其作为饲料的基本指标均符合国家标准。选取室外试验中生长状况较好的4种多年生牧草进行室内模拟实验,研究其对富营养化水体的修复效应。水体TN、TP、NH4+-N、NO3--N、NO2--N、COD在植物浮床系统处理下均显著下降,坦克草处理下去除率最高,对TN、TP、NO3--N、CODMn去除率分别达64.1%,92.1%,70.7%和80.7%。多年生牧草在冬春季对富营养化水体中的氮磷具有较好的净化效果,可作为水体生态修复的优良物种而使用。     

东平湖浮游动物群落特征与水体营养类型评价

2007年对东平湖水域浮游动物群落组成、生物量和生物多样性进行了调查研究,并对水域营养类型进行了评价。结果表明:共检出浮游动物79种,其中原生动物25种、轮虫33种、枝角类8种和桡足类13种;浮游动物规格趋向小型化,原生动物占绝对优势。栖息密度和生物量相对较高,分别为9 459.38(±4 572.12)ind./L和3.07(±0.49)mg/L。5月浮游动物栖息密度表层大于下层,8月则为下层大于表层;5月生物量为表层小于下层,8月为下层大于表层。东平湖浮游动物多样性阈值为2.16~3.70,属于III~V级,物种较为丰富。东平湖水域总体属富营养类型,并随时间推移富营养化程度逐渐加重。     

水库温排水增温模拟及其对富营养化影响分析

温排水导致的水库增温及衍生富营养化是水库生态学领域的研究热点。以承纳温排水的北方某浅水水库为例,利用MIKE21模型构建平面二维水温模拟模型,针对可能出现的调水量和气温极端情况,设定4个情景,分别模拟不同情景下水库水温时空分布规律,对温升带来的富营养化及水华爆发风险进行了分析。结论如下:(1)受温排水口位置、温排水流向及水深共同影响,水库水温呈西高东低,北高南低的分布规律;(2)气温对水库水温的影响较水深更为强烈,取水口1处水域年均温升最大,取水口1和取水口2处水域温升波动较大;(3)调水量和气温等条件变化会导致水华爆发风险变化:除取水口2附近水域外,相对于情景1,情景2和情景3高风险发生时间提前一个月;情景4增温幅度较大,导致东支和取水口1附近高风险延续时段比情景1短一个月。     

富营养化浅水湖泊蓝藻的种群结构和多样性研究

比较研究不同富营养化浅水湖泊中蓝藻种群结构和多样性,对于认识蓝藻水华的区域分布特征具有重要的生态和环境意义.于2009年7月在富营养化严重的滇池、巢湖和太湖各选取4个采样点,采用16S～23S rRNA基因间隔区(Internal transcribed spacer,ITS)序列作为生物标记,通过末端限制性片段长度多态性技术(Terminal restriction fragment length polymorphism,T-RFLP)分析蓝藻种群结构和多样性.实验共得到36个不同的末端限制性酶切片段(Terminal restriction fragment,T-RF),反映3个湖泊中蓝藻种群具有丰富的基因多样性.T-RFLP聚类分析结果表明,在所研究的湖泊中蓝藻种群结构存在空间差异性,其中滇池和巢湖间蓝藻种群结构更为相似.环境因子与蓝藻种群的多元统计分析表明,正磷酸盐(PO4-P)和pH与附着细菌样品蓝藻种群结构动态变化具有显著的相关性(P＜0.05),电导率(Conductivity)和总有机碳(TOC)与浮游细菌样品蓝藻种群结构动态变化具有显著的相关性(P＜0.05).因此,不同湖泊蓝藻水华的基因型和驱动因子存在差异.     

Eutrophication and Recreational Fishing on the Finnish Coast of the Gulf of Finland: A Mail Survey

The Gulf of Finland is one of the most eutrophic areas in the Baltic Sea and is also the main fishing area for more than 150 000 recreational fishermen in Finland. The findings of a mail survey showed that the most important species for the recreational fishery is perch, Perca fluviatilis L. There is no clear evidence that eutrophication has had a harmful effect on the stocks of perch and other species considered important. Heavy fouling of gear, particularly gill nets, is the most acute problem caused by eutrophication to the local recreational fishery. The rapid fouling of passive gear was experienced by 67–86% of all fishermen in the three study areas. A general deterioration in water quality was perceived because only 2–14% of fishermen rated the water quality as excellent. However, a minority of recreational fishermen seem to have adapted or grown accustomed to the deterioration in water quality. Even in the two most eutrophic study areas, 23–31% of recreational fishermen considered that an improvement in local water quality would not benefit their own fishing in any way.     

烟台门楼水库氮磷营养盐的分布及其成因分析

根据近年来对门楼水库监测的数据,利用综合富营养指数法评价,综合分析总磷(TP)、总氮(TN)、叶绿素a(chla)、高锰酸钾指数(CODMn)、透明度(SD)等参数,分析表明烟台门楼水库的水质呈现恶化趋势,水质呈中营养状态,控制水质富营养化的当务之急就是控制入库氮的量.     

湿地花粉含量与入湖营养盐之关系研究

近年来由于工农业污染物和生活污水排放量不断增加以及人类对湖泊湿地环境的破坏,湖泊污染和富营养化问题日趋严重。通过对长江中游湖泊——龙感湖中心沉积物中湿地花粉与入湖营养盐关系的研究,发现湿地植被的破坏是入湖营养盐增加的重要原因。由于人类活动对湿地的破坏,减弱了湿地的生态功能,加速了湖泊生态环境的恶化。     

Is mechanical soil aeration a strategy to alleviate soil compaction and decrease phosphorus and suspended sediment losses from irrigated and rain‐fed cattle‐grazed pastures?

Agriculture is a major source of phosphorus (P) and suspended sediment (SS) losses to aquatic ecosystems promoting eutrophication. Mechanical soil loosening equipments such as topsoil looseners or aerators have been reported to improve the physical quality and infiltration of soils susceptible to livestock damage resulting from treading. We hypothesized that soil aeration would significantly decrease the volume of surface runoff and consequent losses of P and SS compared with non‐aerated soil (control) in cattle‐grazed pasture on a poorly structured silt‐loam soil. Hydrologically isolated plots (2 m long × 1 m wide × 0.15 m deep) were installed in aerated and control plots to collect surface runoff following irrigation or rainfall and analysed for P and SS losses for 1 year. Soil physical properties [% macroporosity, bulk density, saturated hydraulic conductivity (K_sat) and unsaturated hydraulic conductivity (K_unsat at ?1kPa)] were measured in the aerated and control treatments and taken before each irrigation event (n = 12). Six months after mechanical aeration was employed, but before cattle grazing commenced, no significant differences in soil physical quality were found between aerated and control treatments, with the exception of a minor increase in K_unsat for the control plots. This lack of treatment difference continued after grazing and was largely attributed to the re‐settling of the poorly structured and dispersive soil. Flow‐weighted mean concentrations and annual loads of dissolved reactive P (DRP) on the mechanically aerated soil (2.24 kg DRP/ha) were approximately double those from the control treatment (1.20 kg DRP/ha). However, no significant differences were observed between treatments for surface runoff volumes and losses of total P and total SS, which may reflect the similar soil physical conditions exhibited between treatments throughout most of the trial. As observed elsewhere, time (days) since grazing or fertilizer application was found to influence P and/or SS losses. We conclude that aeration did not decrease P and SS losses. Any changes in soil physical properties such as macroporosity were short‐lived and therefore unlikely to influence surface runoff and subsequent P and SS losses for this soil type.