九龙江流域上游浅水湖泊富营养化机制

基于对九龙江上游龙潭湖富营养化水体和沉积物现状的监测结果,通过与国内富营养化深水湖库和流域下游大型富营养化浅水湖泊进行对比,深入探讨了流域上游浅水湖泊富营养化发生的原因及主导机制.流域上游浅水湖泊具有外源污染物输入较少的特点,较下游大型浅水湖泊更易受温度等气候条件和沉积物氧化还原状态的影响,以及外源输入总磷控制具有较强的滞后效应,因此对流域上游浅水湖泊富营养化的控制必须重视内源营养盐释放,特别是结合态磷的内源释放问题.     

基于环境一号卫星CCD数据的洞庭湖夏季富营养状态评价

利用环境一号卫星数据,系统地分析洞庭湖富营养状态的年际时空变化特征.通过星地同步地面实验,建立起洞庭湖水体的叶绿素a浓度遥感反演模型、富营养状态评价模型.利用2009到2013年8月的多期环境一号卫星CCD数据,对洞庭湖富营养状态进行动态监测和分析.结果表明:1洞庭湖区主要以中营养为主.2009到2013年富营养化水体占全湖的面积分别为48.57%、63.84%、51.10%、35.27%、52.10%.2010年富营养化水体占全湖面积比最大,其次是2013年.2洞庭湖富营养水体主要集中在大小西湖、东洞庭湖西部及内湖地区.2009年到2013年大通湖和南湖这两个典型内湖重度富营养水体占全湖的面积比都在逐年下降,水质有好转的趋势.     

长江中下游湖泊水体氮磷比时空变化特征及其影响因素

为弄清长江中下游浅水湖泊水体氮磷比(TN/TP)对湖泊富营养化状况及水系连通性的指示意义,对该区域26个湖泊开展了春、夏两季的水质调查,比较了不同水文、水质状况湖泊之间TN/TP差异,探讨了影响湖泊TN/TP的主要因素.结果发现,长江中下游湖泊TN/TP存在较大的时空差异性,春季TN/TP平均值为21.52±14.28,过水性湖泊、深水湖泊以及富营养化湖泊3种类型水体中,富营养化湖泊的TN/TP较低,为14.38±7.40,深水湖泊的TN/TP最高,为40.97±33.37;夏季调查湖库的TN/TP平均值为21.73±23.78,其中深水湖泊的TN/TP仍为最高,达96.38±45.91,富营养化湖泊的TN/TP仍为最低,达10.91±4.44.春、夏相比,过水性湖泊和深水湖泊夏季的TN/TP显著上升,而富营养化湖泊却明显下降,且降幅随富营养化程度升高而加大.相关性分析发现,无论是春季还是夏季,湖泊TN/TP都与水体深度显著正相关.此外,湖泊富营养化程度越高,TN/TP与浮游植物生物量的关系就越弱,富营养化程度越低,TN/TP越高,磷对浮游植物生长的限制越明显.研究表明,长江中下游湖泊富营养化治理营养盐策略上,多数湖泊控磷更为重要,在一些富营养化较为严重的湖泊,局部疏浚、合理挖深、外源控制和调整渔业生产方式等是值得探索的修复途径.     

鄱阳湖流域人为氮磷输入演变及湖泊水环境响应

人类活动导致的氮磷营养盐富集是我国湖泊富营养化问题形成的重要驱动力.鄱阳湖是我国最大的淡水湖泊,随着流域经济社会的迅速发展,湖体营养盐水平上升,降低了鄱阳湖及长江中下游地区的水环境质量.然而,人类对鄱阳湖流域氮磷输入的影响程度尚不明确,湖体氮磷浓度与流域人为氮磷输入的关系也缺乏定量研究.因此,本研究基于人为净氮输入模型(NANI)、人为净磷输入模型(NAPI)和多元统计回归模型,评估了鄱阳湖流域1949—2013年人类活动导致的氮磷输入量,构建了人为氮磷输入与湖泊氮磷浓度的响应模型.结果表明,研究期内鄱阳湖流域的人为净氮输入和人为净磷输入分别增长6倍和15倍,化肥施用是20世纪80年代以来的主要增长因子;鄱阳湖氮磷浓度与流域人为氮磷输入显著相关,根据多元回归模型的可决系数,NANI可解释88%的湖体TN浓度变化,NAPI和湖泊平均水位可解释64%的TP浓度变化.提高氮磷的循环利用率同时维持湖泊生态水位对于降低鄱阳湖富营养化水平具有重要意义.     

洞庭湖近20年水质与富营养化状态变化

利用近20年水质监测资料,系统地分析了洞庭湖水质与营养状态的时空变化特征. 结果表明,受流域社会经济发展等因素的综合影响,洞庭湖水质整体呈下降趋势,水体富营养化日趋严重,东洞庭湖的富营养程度稍高于西洞庭湖和南洞庭湖. 洞庭湖水体主要污染物为TN和TP, ρ(TN)、ρ(TP)年均值分别为1.08~1.93和0.026~0.203 mg/L. 洞庭湖水体中ρ(Chla)与ρ(TN)呈显著正相关;浮游植物数量与ρ(TN)、ρ(TP)呈显著正相关,与最大流量呈显著负相关. 2007年洞庭湖流域造纸企业污染整治后,洞庭湖水体中ρ(COD_Cr)降低,但ρ(TN)、ρ(TP)仍呈上升之势,浮游植物数量显著增加. 洞庭湖水体富营养化治理应以控制面源污染为重点.      

太湖水华期营养盐空间分异特征与赋存量估算

基于2013年7月的空间高密度采样数据,对太湖水华期水体营养盐进行了空间分异特征分析及赋存量估算,探讨了大型浅水湖泊不同生态类型湖区水华与营养盐的相关关系及样点设置的代表性.结果发现,水华期太湖水体营养盐及叶绿素a浓度(CHL)总体上均呈现由西北向东南降低的趋势;氮主要以溶解态存在,占总氮(TN)的76.28%,磷主要以颗粒态赋存,占总磷(TP)的66.38%.采用主成分分析和聚类分析,可以将采样点分为相互之间具有显著性差异的4个区域:第一区位于西北湖区,代表水华严重的重富营养湖区;第二区主要包括梅梁湾及南太湖的入湖河口一带湖区,代表水华和富营养化程度都相对中等的湖区;第三区包括湖心区和西南湖区,代表中等污染但水华频现湖区;第四区包括贡湖湾、胥口湾和东太湖等其他区域,代表水华影响较弱、水质较好湖区.分区统计分析表明,不同湖区影响浮游藻类生长的因子也不同:从全湖来看,与CHL显著相关的营养盐指标为TP、TN、溶解性总氮(TDN)和硝态氮(NO-3-N),而在第一区则为TP和TDN,第二区为TN和TDN,第三区为TP、磷酸盐(PO3-4-P)和TDN,第四区为PO3-4-P、溶解性总磷(TDP)和亚硝酸盐(NO-2-N).基于空间插值获得调查期间太湖水体TN、TDN、TP和TDP的赋存量分别为12 800、9 800、445和150 t.研究表明,作为一个大型浅水湖泊,因蓝藻水华空间迁移积聚特征和生态类型异化等特征,太湖水华期的营养盐具有高度空间异质性,对于此类大型浅水湖泊的监测与评价,应当考虑点位的合理布设及结果的恰当解读,避免因监测布点和统计方法不当而以偏概全.     

综合营养状态指数法在陶然亭湖富营养化评价中的应用

根据2006年-2010年陶然亭湖富营养化监测数据,采用综合营养状态指数法,分别从年均值及月份变化两方面对陶然亭湖的营养状态进行详细的分析和评价。结果表明,2006年-2010年陶然亭湖的营养状态指数呈现逐年下降的趋势,营养级别从重度富营养下降至中度富营养。湖泊富营养化程度随季节变化十分明显,富营养化程度在夏季和秋季形成高峰,冬季和春季一般较低。由于污水处理厂的再生水水质较差,补给到景观湖泊,加剧了富营养化程度。可以从污水处理厂加强对再生水质中氮、磷的处理和控制、利用生物-生态修复技术等方面采取措施来降低陶然亭湖的富营养化程度。     

Establishing eutrophication assessment standards for four lake regions, China

The trophic status assessment of lakes in different lake regions may provide important and fundamental information for lake trophic state classification and eutrophication control. In this study, a region-specific lake eutrophication assessment standard was established through a frequency distribution method based on chlorophyll-a concentration. The assessment standards under the oligotrophic state for lakes in the Eastern plain, Yungui Plateau, Northeast Plain and Mountain Mongolia-Xinjiang regions are total phosphorus of 0.068, 0.005, 0.011, 0.005 mg/L; total nitrogen of 1.00, 0.16, 0.37, 0.60 mg/L; Secchi depth of 0.60, 8.00, 1.55, 3.00 m; and CODMn of 2.24, 1.00, 5.1 l, 4.00 mg/L, respectively. Moreover, a region-specific comprehensive trophic level index was developed to provide an understandable assessment method for the public. The results indicated that the frequency distribution analysis based on chlorophyll-a combined with trophic level index provided a useful metric for the assessment of the lake trophic status. In addition, the difference of eutrophication assessment standards in different lake regions was analyzed, which suggested that the sensitivities of algae to nutrients and the assessment standard of trophic status possessed significant regional differences for the four lake ecoregions. Lake eutrophication assessment standards would contribute to maximizing the effectiveness of future management strategies, to control and minimize lake eutrophication problems.     

底栖藻对水丝蚓生物扰动效应的抑制研究

霍甫水丝蚓(Limnodrilus hoffmeisteri)是富营养化湖泊中的底栖动物优势种,通过生物扰动可以提高水体营养盐浓度,并促进浮游植物生长.富营养浅水湖泊经生态修复后,水体透明度会得到改善,有利于底栖藻快速生长,从而降低水体营养盐水平.那么,底栖藻能否抑制水丝蚓对富营养水体水质的不良影响?为此,本文开展了双因素(底栖藻和水丝蚓)的室外受控实验,结果表明:在无底栖藻处理中,水丝蚓显著提高了水体总氮(TN)、总磷(TP)、总溶解磷(TDP)和叶绿素a(Chl-a)浓度,同时显著降低水体溶解氧(DO)浓度;而在有底栖藻处理中,水丝蚓对水体TP、DO及Chl-a浓度的影响不显著.研究结果表明,水丝蚓的生物扰动提高了水体营养盐和浮游植物浓度,促进水体富营养化.但底栖藻群落的发展能在一定程度上抑制水丝蚓的生物扰动效应.     

鄱阳湖入湖河流氮磷水质控制限值研究

鄱阳湖近年氮磷营养物浓度逐步升高,入湖河流是鄱阳湖氮磷输入的重要途径.采用BATHTUB模型建立了鄱阳湖入湖河流与湖区ρ（TP）、ρ（TN）的响应关系,模拟了入湖河流执行GB 3838—2002《地表水环境质量标准》中不同氮磷标准限值对湖区水质的影响,发现当入湖河流ρ（TP）执行河流Ⅲ类标准限值或超过Ⅲ类标准限值时,对应湖区ρ（TP）超标;入湖河流执行Ⅲ类及以上湖泊水质标准限值时,湖区水质可以达到Ⅲ类保护目标,但对入湖河流存在一定的过保护现象.因此,以满足现行湖泊水质达标为情景,以湖泊ρ（TP）、ρ（TN）各类别标准限值为目标,试算了入湖河流氮磷控制限值,提出了鄱阳湖入湖河流的氮磷控制限值建议方案,其中鄱阳湖湖体水质目标为Ⅲ类时,入湖河流ρ（TP）、ρ（TN）控制限值分别为0.075和1.20 mg/L,此时入湖河流氮磷控制限值方案既能保证湖泊水质达标,又不会造成对河流的水质控制过于严格.研究显示,基于湖泊水环境质量达标情况试算的入湖河流氮磷所需控制限值,建议可作为解决入湖氮磷污染控制问题的参考.      

Controlling cyanobacterial blooms by managing nutrient ratio and limitation in a large hypereutrophic lake: Lake Taihu, China

Excessive nitrogen (N) and phosphorus (P) loading of aquatic ecosystems is a leading cause of eutrophication and harmful algal blooms worldwide, and reducing nutrient levels in water has been a primary management objective. To provide a rational protection strategy and predict future trends of eutrophication in eutrophic lakes, we need to understand the relationships between nutrient ratios and nutrient limitations. We conducted a set of outdoor bioassays at the shore of Lake Taihu. It showed that N only additions induced phytoplankton growth but adding only P did not. Combined N plus P additions promoted higher phytoplankton biomass than N only additions, which suggested that both N and P were deficient for maximum phytoplankton growth in this lake (TN:TP = 18.9). When nutrients are present at less than 7.75-13.95 mg/L TN and 0.41-0.74 mg/L TP, the deficiency of either N or P or both limits the growth of phytoplankton. N limitation then takes place when the TN:TP ratio is less than 21.5-24.7 (TDN:TDP was 34.2-44.3), and P limitation occurs above this. Therefore, according to this ratio, controlling N when N limitation exists and controlling P when P deficiency is present will prevent algal blooms effectively in the short term. But for the long term, a persistent dual nutrient (N and P) management strategy is necessary.     

水体及沉积物氮磷水平对附植藻类的影响

为了探讨湖泊富营养化过程中沉积物及水体氮、磷浓度对附植藻类的影响,通过室内模拟实验,研究了水体及沉积物氮、磷升高对苦草(Vallisnerianatans(Lour.) Hara)上附植藻类生长、群落组成及其体内氮、磷含量的影响.结果表明,在实验条件下,随着水中氮、磷含量升高,附植藻类生物量及附植藻类氮、磷含量均呈极显著增加(p0.01).随着水体可获得的氮、磷浓度升高,附植藻类的相对丰度有所变化,舟形藻(Navicula)、小球藻(Chlorella)及微囊藻(Microcystis)相对丰度随着氮、磷水平的升高而下降,直链藻(Melosira)则相反,但舟形藻、直链藻、微囊藻、小环藻(Cyclotella)和小球藻均为群落的优势属种.沉积物氮、磷含量升高对附植藻类生物量、优势种丰度及群落氮、磷含量影响较小,均未达到显著水平(p0.05).在实验条件下,沉积物氮、磷含量对附植藻类影响不大,而水体氮、磷浓度升高显著地促进了附植藻类生长.研究结果也为解释富营养化湖泊沉水植物衰退及消亡提供了一定的科学依据.     

Control concept and countermeasures for shallow lakes'eutrophication in China

Research on lake eutrophication in China began in the early 1970s, and many lakes in China are now known to be in meso-eutrophic status. Lake eutrophication has been showing a rapidly increasing trend since 2000. Investigations show that the main reasons for lake eutrophication include a fragile lake background environment, excessive nutrient loading into lakes, excessive human activities, ecological degeneration, weak environmental protection awareness, and lax lake management. Major mechanisms resulting from lake eutrophication include nutrient recycling imbalance, major changes in water chemistry (pH, oxygen, and carbon), lake ecosystem imbalance, and algal prevalence in lakes. Some concepts for controlling eutrophication should be persistently proposed, including lake catchment control, combination of pollutant source control with ecological restoration, protection of three important aspects (terrestrial ecology, lake coast zone, and submerged plant), and combination of lake management with regulation. Measures to control lake eutrophication should include pollution source control (i.e., optimize industrial structural adjustments in the lake catchment, reduce nitrogen and phosphorus emission amounts, and control endogenous pollution) and lake ecological restoration (i.e. establish a zone-lake buffer region and lakeside zone, protect regional vegetation, utilize hydrophytes in renovation technology); countermeasures for lake management should include implementing water quality management, identifying environmental and lake water goals, legislating and formulating laws and regulations to protect lakes, strengthening publicity and the education of people, increasing public awareness through participation in systems and mechanic innovations, establishing lake region management institutions, and ensuring implementation of governance and management measures.     

南湖富营养化主要控制因子分析

全面分析了南湖湖泊系统中营养物之间、营养物与藻类生长之间的相互关系,探讨了各种环境因子对南湖富营养化的影响,结合藻类增长潜力试验结果确定南湖富营养化的主要控制因子。结果表明,光、温度、碳、氮不能成为南湖富营养化的主要控制因子,控制南湖富营养化的关键在于控制磷。      

不同营养湖泊沉积物中210Pbex和营养盐垂向分布特征及相关性分析

对比分析了两个不同营养湖泊抚仙湖和滇池湖中心部位沉积物柱芯放射性核素210Pbex和营养盐(TOC、TN和TP)的垂向分布特征,探讨了两个湖泊不同湖区沉积物柱芯中210Pbex与营养盐(TOC、TN和TP)之间的相关关系.结果表明,两个湖泊沉积物柱芯中210Pbex和营养盐各个指标的垂向分布存在差异,总体上滇池沉积物柱芯中210Pbex的波动变化幅度略高于抚仙湖.滇池表层沉积物中210Pbex较为紊乱的分布特征与人类活动影响下的沉积物中Pb的物理化学迁移有关.沉积物中营养盐各个指标的变化则与特定历史时期不同强度的自然演化和人类活动双重因素影响密切相关.放射性核素210Pbex和营养盐各个指标之间的相关关系与两个湖泊或同一湖泊不同湖区的营养水平高低有关,其变化关系为富营养化湖泊滇池>贫营养湖泊抚仙湖,抚仙湖北岸>南岸.就单个营养盐指标与210Pbex之间的相关关系而言,TOC最强,TP次之,TN最弱.     

Responses of alkaline phosphatase activity to wind-driven waves in a large, shallow lake: Implications for phosphorus availability and algal blooms

Phosphorus is a vital nutrient for algal growth, thus, a better understanding of phosphorus availability is essential to mitigate harmful algal blooms in lakes. Wind waves are a ubiquitous characteristic of lake ecosystems. However, its effects on the cycling of organic phosphorus and its usage by phytoplankton remain poorly elucidated in shallow eutrophic lakes. A mesocosm experiment was carried out to investigate the responses of alkaline phosphatase activity fractions to wind waves in large, shallow, eutrophic Lake Taihu. Results showed that wind-driven waves induced the release of alkaline phosphatase and phosphorus from the sediment, and dramatically enhanced phytoplanktonic alkaline phosphatase activity. However, compared to the calm conditions, bacterial and dissolved alkaline phosphatase activity decreased in wind-wave conditions. Consistently, the gene copies of Microcystis phoX increased but bacterial phoX decreased under wind-wave conditions. The ecological effects of these waves on phosphorus and phytoplankton likely accelerated the biogeochemical cycling of phosphorus and promoted phytoplankton production in Lake Taihu. This study provides an improved current understanding of phosphorus availability and the phosphorus strategies of plankton in shallow, eutrophic lakes.     

富营养化驱动下西凉湖百年来生态系统演化轨迹

长江中下游浅水湖泊是区域社会可持续发展的重要自然资源,富营养化问题致使该地区湖泊发生草-藻转换,限制了湖泊生态系统服务的供给.湖泊环境问题是生态系统受外力长期胁迫的结果,湖泊生态治理与保护须充分了解系统的演化规律,但是相关认识受限于长期监测资料的缺失.为了厘清长江中下游地区典型草型湖泊生态系统演化轨迹,更有效管理受损湖泊,选择西凉湖为研究对象,利用沉积记录代用指标粒度、元素和硅藻等,在高分辨率放射性核素定年的基础上,分析了近150年来西凉湖生态系统的演变规律.结果表明,西凉湖在20世纪40年代之前水体清澈,营养水平较低,沉水植物相对较少;而20世纪40年代以后,人类活动逐渐增强导致湖泊营养水平升高,水生植被增多;硅藻群落结构逐渐由浮游硅藻组合向底栖和附生硅藻组合演替,同时沉积物营养不断增加,表明以流域土地利用方式改变、围垦和渔业养殖等为代表的人类活动深刻改变了湖泊生态系统结构.研究认为虽然湖泊营养在20世纪70代之后一直维持在较高水平,达到富营养化标准,但沉水植被的生长限制了湖泊藻类浓度,西凉湖并未藻类暴发.同时也发现外源营养的增加通过湖泊初级生产者深刻影响了湖泊的地球化学循环,造成了...     

A bibliometric review of nitrogen research in eutrophic lakes and reservoirs

The global application of nitrogen is far greater than phosphorus, and it is widely involved in the eutrophication of lakes and reservoirs. We used a bibliometric method to quantitatively and qualitatively evaluate nitrogen research in eutrophic lakes and reservoirs to reveal research developments, current research hotspots, and emerging trends in this area. A total of 2695 articles in the past 25 years from the online database of the Scientific Citation Index Expended(SCI-Expanded) were analyzed. Articles in this area increased exponentially from 1991 to 2015.Although the USA was the most productive country over the past 25 years, China achieved the top position in terms of yearly publications after 2010. The most active keywords related to nitrogen in the past 25 years included phosphorus, nutrients, sediment, chlorophyll-a, carbon,phytoplankton, cyanobacteria, water quality, modeling, and stable isotopes, based on analysis within 5-year intervals from 1991 to 2015 as well as the entire past 25 years. In addition, researchers have drawn increasing attention to denitrification, climate change, and internal loading. Future trends in this area should focus on:(1) nutrient amounts, ratios, and major nitrogen sources leading to eutrophication;(2) nitrogen transformation and the bioavailability of different nitrogen forms;(3)nitrogen budget, mass balance model, control, and management;(4) ecosystem responses to nitrogen enrichment and reduction, as well as the relationships between these responses; and(5)interactions between nitrogen and other stressors(e.g., light intensity, carbon, phosphorus, toxic contaminants, climate change, and hydrological variations) in terms of eutrophication.     

程海湖夏冬季浮游植物群落结构与富营养化状况研究

为了解程海湖浮游植物群落特征及其富营养化现状,对程海湖的水体理化指标和浮游植物群落结构进行了系统调查,分析了夏、冬季节程海湖水质状况、浮游植物群落结构特征及其与环境因子之间的关系,并运用综合营养状态指数法和藻类生物学法评价了程海湖的营养状态.结果表明,调研期间程海湖氮、磷浓度较高,水体中总磷(TP)浓度为0.03～0.19 mg·L~(-1),总氮(TN)为0.38～3.08 mg·L~(-1),综合营养状态指数(TLI)在49.3～54.4之间波动,已经达到轻度富营养水平;藻密度变化范围为1.54×10~6～1.65×10~7个·L~(-1),已超过常规湖泊的水华暴发阈值范围;浮游植物以蓝藻、绿藻为主,Shannon-Wiener多样性指数大多数为1～3,Pielou均匀度指数为0.18～0.72,部分时间段藻类多样性偏低,呈现出典型的蓝藻门为优势的富营养化状态,亟需对其进行生态保护与管理.     

城市富营养湖泊沉积物中磷负荷及其释放对水质的影响

以南京玄武湖为研究对象,探讨了城市富营养湖泊沉积物中磷的分布、化学形态和负荷量:通过模拟实验深入研究了溶解氧、pH值、温度、扰动等环境因子对沉积物中磷的释放影响．进而得出磷释放速率．并对pH值影响作出校正,计算出沉积物中磷对湖水释放量,为玄武湖富营养化防治提供科学依据。