通江城市河道浮游植物分布研究——以镇江市古运河为例

为了解通江城市河道浮游植物分布动态规律，同时为制定有效的水环境质量改善方案，对镇江市古运河的浮游植物组成与分布变化进行现场调查与分析，探讨了环境因子变化对河道浮游植物结构与数量的影响。结果表明，研究区共检出藻类6门38属，其中绿藻门、蓝藻门和硅藻门为3个常见门类。河道内藻类细胞密度与生物量排序为春季>秋季>夏季>冬季。对比河源采样点，河道内藻类细胞密度、生物量均在春、秋季大幅增长，藻类种类组成比例也逐渐由硅藻门为主过渡到以绿、蓝藻为主，但在夏、冬季这种变化趋势不明显。水动力、营养盐浓度、水温以及水体悬浮泥沙含量等多环境因子影响了河道内藻类生长与繁殖条件，其中因受闸控影响的水动力学条件变化是造成藻类分布变化的关键诱发要素。〖     

三峡水库蓄水对香溪河水环境的影响及对策研究

通过监测论证三峡建库后形成香溪河回水库湾水环境条件改变特征,评价表明水质由轻污染至重污染趋势发展。确定库湾周边的工业、生活污染点源、磷矿面源是构成水污染的主要负荷。指出溶解氧沿河道下游沿程逐渐减小,复氧系数降低,是引起水质恶化,破坏库湾生态平衡的主要因素。磷浓度过高将引起三峡水库局部水域富营养化,预测了总磷浓度沿程变化趋势。针对已发生和潜在的水环境污染问题,提出了加强流域非点源污染的管理、实施总量控制、建立污染源在线监测系统、立项建设污染治理工程、开展河湖水域接触氧化直接净化技术的科研究和实践、制定《三峡库区水污染防治法》地方法规、正确处理资源开发与环境保护协调发展的关系、走可持续发展道路等项防治对策与建议。     

巢湖藻华易堆积区蓝藻时空分布的研究

巢湖西半湖采样分析结果表明夏季蓝藻水华主要集聚于湖滨带。因此选择西半湖藻华易堆积的区域,并监测在风力驱使下蓝藻水华的时空分布规律,分析湖滨带浮游植物生物量与理化因子的相关性。结果表明：湖滨带水华生物量的分布容易受到风向和天气的影响;水体的叶绿素a浓度与总氮（TN）、总磷（TP）和高锰酸钾指数（CODMn）呈显著的正相关（p<001）;湖滨带水体中微囊藻（Microcystis）的生物量几乎占据水体总浮游植物生物量的95%以上,而且越靠近湖岸带微囊藻的生物量所占的比例越大。据此,可以选择湖滨带水华易聚集区作为蓝藻水华尤其是微囊藻去除的重点区域,以有效地削减蓝藻水华污染,从而为巢湖水生态系统的修复创造条件     

长江源区浮游植物群落结构及分布特征

地处青藏高原腹地的长江源区是长江流域的水源涵养地和生态系统的天然屏障,同时也是自然生态系统最敏感、生态环境十分脆弱的地区,浮游植物作为水体生态系统中的初级生产者,其群落结构对反映水体质量具有重要的指示作用。为探究长江源区水环境特性和浮游植物群落特征,于2018年3月份与10月份对长江源区10个典型河段的水环境因子与浮游植物群落组成进行了系统调查。结果显示:10月份各调查河段流速、浊度、水温及电导率等水环境参数均比3月份高;同一月份中,楚玛尔河的浊度、盐度、电导率等水环境参数均显著高于其余河段;两个月份各调查河段的pH、溶解氧以及亚硝酸盐氮等指标差异不显著。采样调查共鉴定出浮游植物4门28属58种,其中以硅藻、绿藻和蓝藻物种数占优,分别占总数的79.3%、10.4%和8.6%。调查期间,长江源区浮游植物密度在6.06×10~4～39.90×10~4 cells·L~(-1)之间,平均生物量为0.59 mg·L~(-1)。浮游植物优势种有美丽颤藻(Oscillatoria formosa)、普通等片藻(Diatoma vulgare)、脆杆藻(Fragilaria sp.)、针杆藻(Synedra sp.)、舟形藻(Navicula sp.)、桥弯藻(Cymbella sp.)、小球藻(Chlorella sp.)等。两个月份Shannon-Wiener多样性指数(H’)均值分别为3.06和3.12,Margalef丰富度指数(D)均值为1.17和1.52,Pielou均匀度指数(J)均值为0.90和0.82。结合水体营养盐指标、浮游植物密度及多样性指数等指标对水质评价,长江源区水质总体呈无污染或轻度污染状态。     

金沙江干流浮游植物群落结构特征及其时空变化

为研究金沙江干流浮游植物群落结构及其时空分布特征,于2017～2018年春秋两季对干流14个断面进行调查分析。调查结果显示:金沙江干流水域共分布浮游植物8门100种(含变种),主要由硅藻(56%)、蓝藻(22%)、绿藻(11%)组成,浮游植物密度变化范围为0.019 3×10~6～0.341 0×10~6cells/L,浮游植物生物量变化范围为0.016～0.434 mg/L,各江段存在显著性差异。Shannon多样性指数变化范围1.168～2.519,Pielou均匀度指数变化范围为0.559～0.876,Margalef指数变化范围为1.573～3.36,各江段多样性指数变化各异,金沙江干流水环境综合评价为中污染状态。等级聚类和排序结果表明,2017、2018年的春秋两季样本点群落均分为3组。上中下游在不同季节、年份里表现出不同程度的相似性,由于不同断面的环境差异造成了浮游植物群落的时空差异。时间上,金沙江干流浮游植物群落结构上每个季节演替明显,既有延续也有交替;空间上,采样点从上游至下游浮游植物群落越均匀旺盛,具有较明显的空间趋异性,聚类和排序较好的揭示了金沙江干流各江段浮游植物分布组成、种类数量和生境的相似性。     

巢湖水及沉积物中总磷的分布变化特征

磷是导致巢湖水体富营养化的主要营养物质。采集大量巢湖表层水和沉积物样品,通过检测上覆水和沉积物中总磷含量,分析巢湖水体中磷的时空变化及赋存特征。结果显示:巢湖南淝河和裕溪河河口的上覆水中总磷含量值时间变化特征为8月5月3月12月;且南淝河口总磷含量年均值超过地表水Ⅴ类水质标准,明显高于裕溪河口值;表层水和沉积物中总磷含量在空间分布上呈西高东低趋势,最高值均出现在靠近合肥市河口处。巢湖周边土壤及湖区磷的等值线分布表明:杭埠河流域农业污染、东巢湖东南部水土流失可能是巢湖磷面源污染的主要来源。巢湖上覆水和沉积物中总磷的相关系数为0.515,蓝藻爆发期全湖表层沉积物中总磷含量显著减少,揭示目前内源磷释放已是巢湖富营养化的主要因素。结果将对巢湖流域的污染综合防治及蓝藻治理工作提供科学依据。     

苏皖交界河网区浮游植物群落结构及其与环境因子关系的研究

苏皖交界处的石臼湖是长江下游唯一的通江淡水湖,通过青弋江和姑溪河直接与长江相连,形成了复杂的河网水系。为探讨这种复杂的河网水系中浮游植物种群结构特征,2012年平水期和枯水期分别对石臼湖及其周边入湖支流进行了浮游植物调查,研究河网水系中河网与湖区浮游植物的种类组成、季节变化及与环境因子的关系。结果显示:共采集到浮游植物105种,平水期与枯水期种类数差别不大,两次调查均出现的种类约有70%相同;浮游植物丰度最高可达1×108cell/L,达到了水华暴发的标准。优势种类主要绿藻门和蓝藻门为主,但是从生物量来看硅藻门占优。排序分析显示河网区域浮游植物季节演替明显,且河网与湖区浮游植物群落结构差异明显,进一步分析则表明影响浮游植物主要的环境因子是氮、磷等营养元素。     

Variation of nutrient and metal concentrations in aquatic macrophytes along the Rio Cachoeira in Bahia (Brazil)

The use of cuprous fungicides in cocoa production in the southern part of the state of Bahia (Brazil) for decades has caused an accumulation of copper in various components of the cocoa plantations, and a contamination of regional freshwater ecosystems is suspected. Urban and industrial sources are supposed to contribute to water pollution and eutrophication of the Rio Cachoeira, the main river in this region. In order to study the metal contamination and nutritional status of this freshwater ecosystem, samples of the aquatic macrophytes Eichhornia crassipes and Pistia stratiotes were collected at seven sites along the river course. The samples were analysed for their copper, aluminium, chromium, nitrogen and phosphorus concentrations. The levels of heavy metals increased in the downstream direction, particularly in the roots of water hyacinth. A dramatic increase of nitrogen and phosphorus concentrations in water as well as in plant tissues was found in samples collected downstream from the city of Itabuna. Metal input and eutrophication were attributed to agricultural, industrial and urban sources in the region. Biomonitoring of the water quality using aquatic macrophytes as accumulative indicator plants is recommended in addition to chemical water analyses.     

鄱阳湖区氮磷污染物分布、转移和削减特征

根据入湖污染负荷监测、调查资料和不同水文条件下流场-水质同步监测资料,应用数理统计方法,研究了鄱阳湖氮磷营养物质分布、转移和削减特征。研究结果显示:(1)总磷、总氮是影响鄱阳湖水环境质量的主要污染物,入湖污染负荷与入湖径流水量紧密正相关。(2)鄱阳湖换水周期短,水流更换频繁,氮磷污染物在湖区不会充分混合;氮磷超标水域随着水体流动,逐步向下游转移、扩散;湖水位处于消落状态,通江水道部分水域氮磷浓度超标。(3)湖相状态水环境比河相好,湖相状态一般不会出现大面积的总氮和总磷同时超标。(4)鄱阳湖水环境勉强维持Ⅲ类标准,如果出现损害环境的人类活动,脆弱的水环境将会恶化。针对这些特征提出了保护鄱阳湖"一湖清水"的对策建议。     

近20年来湘江水质变化分析

根据1981~2000年湘江的水质监测数据,选用危害较大的10项污染指标,采用均值指数法对近20年来湘江水质变化进行了分析,并对湘江干流不同河段水质进行了比较。结果表明：湘江总体水质在20世纪90年代呈恶化趋势,致使污染加剧的主要因子是总大肠菌群、总磷、石油类和总汞;主要污染源为工业污染和生活废水污染,近年来生活废水污染日益突出,工业污染中重金属污染明显;在干流不同河段中,株洲、湘潭和长沙河段污染最为严重;估计未来湘江的生活污染和农业污染还会加剧。因此,为确保经济和环境协调发展,湘江污染治理任务依然任重道远。在加大宣传力度,提高公民环境意识,加快城市污水处理设施建设和发展生态农业的同时,应将湘江流域城市生态水源建设提上议事日程。     

太湖典型丘陵水源地水质时空变化及影响因素分析——以平桥河流域为例

基于太湖流域典型丘陵水源地平桥河流域12个采样点的水质监测数据,综合运用聚类分析和主成分分析法对平桥河流域水质时空变化及影响因素进行分析。聚类分析显示,按照水质相似性将平桥河流域水质分为枯水期、平水期、丰水期3个季节时段和中上游丘陵河谷区、下游紧邻平桥镇的平原区、下游暗沟出口区3个典型空间区域。主成分分析显示:(1)枯水期水质以氮污染为主导因素,磷和有机污染次之,受流量减小、流速缓慢导致的营养盐富集的影响加大;平水期水质以氮污染为主导因素,磷污染次之,受茶园等大量施肥导致的农业面源污染的影响;丰水期水质以氮和磷污染为主导因素,受到水稻种植等农业活动和大量降雨径流的影响。(2)中上游丘陵河谷区水质以氮和磷污染为主导因素,有机污染次之,受到茶园种植等农业活动导致的面源污染的影响;下游紧邻平桥镇的平原区水质以氮和磷的污染为主导因素,有机污染次之,受到居民生活污水和农业生产的影响;下游暗沟出口区水质以氮污染为主导因素,有机污染和磷污染次之,受到生活污水、农业生产和畜禽养殖的影响。研究结果可为太湖流域丘陵区水源地保护和管理提供参考。     

三峡水库水质变化趋势研究

为全面研究三峡水库蓄水之前至175 m蓄水运行期库区水质变化趋势和因蓄水导致水文条件变化后悬浮物、高锰酸盐指数、总磷等主要污染因子变化及其相互关系,通过对2000~2015年三峡水库水体水质状况进行分析,得出如下结论:三峡水库干流水质较好,其受水期及水库蓄水调度影响明显但逐渐减弱。受蓄水导致的水流条件变化、上游来水、支流汇入及沿程点面源污染等因素影响,干流沿程各断面水质变化趋势不完全一致;除清溪场和沱口断面外,从库尾到库首水质评价结果优于Ⅲ类的比例总体呈上升趋势。受蓄水影响,御临河、小江、大宁河及香溪河河口断面水质均呈下降趋势。三峡水库上游来水悬浮物含量变化与水期存在较好相关性,但自2013年开始上游来水各水期悬浮物含量均下降,悬浮物通量较2013年之前平均降低约80%。水库库中、库首断面近年来悬浮物含量在丰水期和平水期下降,其后逐渐趋于稳定,枯水期变化不明显。蓄水后主要支流河口悬浮物含量大部分时段低于库区干流同期,上游支流河口断面悬浮物含量受水期影响较库区中下游支流河口明显。干支流各断面高锰酸盐指数和总磷在各水期变化趋势各异,上游断面丰水期变化较下游断面明显;随着蓄水进程,各断面高锰酸盐指数和总磷在平水期和枯水期之间、断面间差异越来越小。悬浮物含量与高锰酸盐指数、总磷等参数之间存在一定的相关性,但在较长时间范围,不能通过拟合等手段将水样一种状态的测定结果推出样品另一种状态近似检测结果。     

三峡水库“水华”成因初探

2004年3月、5月、7月、8月、10月和2005年5月对长江干流29个站点进行了5次调查。2004年3月（旱季）在三峡库区坝前（秭归）发现藻类“水华”，藻类密度达2.73×106 cells/L，优势种类为拟多甲藻。2004年8月（雨季）和2005年4月（旱季）沿香溪河下游及河口区以及香溪河口到三峡大坝干流江段进行了2次6个断面分层调查，两次调查中在香溪河下游以及香溪河口区发现了严重的藻类“水华”，藻类密度高达1.87×107 cells/L 和1.67×107 cells/L，优势种分别为蓝隐藻（1.84×107 cells/L）和美丽星杆藻 (1.34×107 cells/L)。相关分析结果表明：三峡库区干流藻类数量和生物量与水库的出水流量有着显著的负相关(Spearman，r=-1.000, r=-0.900, p<0.05)，而与可溶性营养盐（NO3 N, PO4 P, SiO3 Si）的浓度无显著的相关性；在2004年7~8月（雨季）香溪河下游及河口区浮游植物生物量与主要营养盐（NO3 N, PO4 P,SiO3 Si）的浓度呈显著负相关（Spearman,p<0.01, p<0.05,p<0.01, n=21）；在2005年4月（旱季）该河段藻类密度与主要营养盐（NO3 N N,SiO3 Si）呈显著负相关 (Spearman, p<0.05，p<0.01,n=28)，但与PO4 P无显著的相关性。香溪河口到秭归的坝前库区河段藻类数量与主要营养盐（NO3 N, PO4 P,SiO3 Si）没有显著相关性(Spearman, │r│<0.2, n=20)。然而香溪河下游及河口区主要营养盐（NO3 N, PO4 P, SiO3 Si）浓度却低于长江干流。可以推断三峡库区蓄水后干流和支流发生“水华”的最主要原因是筑坝后库区内水动力条件的改变而非营养盐浓度较高。随着三峡工程的全面完工，库区内水体滞留时间的进一步延长，三峡库区水体富营养化趋势将会进一步加剧。     

成都平原毗河下游生态环境需水量研究

20世纪90年代以来,河流生态环境需水成为生态水文学研究的重要内容。阐述了基于国际上新兴发展的生态水文学理论的生态环境需水量的概念和内涵。并以毗河为例,用能反映时间尺度的河流流量来表达生态环境需水量,而不是传统意义上的水量。为了与水资源配置的时间单元协调起来,对3个代表年〖WTBX〗P〖WTBZ〗=50%（1968年）,〖WTBX〗P〖WTBZ〗=75%（1986年）,〖WTBX〗P〖WTBZ〗=90%（1987年）分别进行生态环境需水量的计算。根据毗河的自然条件,利用Montana法计算了河道维护水生生境最小需水量和最适宜需水量;蒸发需水量由水面宽度、河道两断面间平均长度、河道蒸发深度三者确定;结合河道功能区划和水质目标,计算了污染物稀释需水量。最终确定毗河下游河道的最小生态环境需水量为20.64 m3/s,最适宜生态环境需水量为25.84 m3/s。     

Estimation of sources of total phosphorus in a river basin and assessment of alternatives for river pollution reduction

The methodology of material flow analysis is presented and applied to developing a phosphorus balance in a river basin and evaluating different scenarios for pollution reduction. The method is based on the balance principle: inputs and outputs of each phosphorus-related subsystems were balanced. The application of the methodology strategies was illustrated by means of a case study of the Krka River, Slovenia. The results showed that besides effluents from wastewater treatment plants, agriculture contributed significantly to the total annual phosphorus load. After establishing the present levels of phosphorus balance, different scenarios were considered: different stages of wastewater treatment as well as management of agricultural activities. The present emission of phosphorus is estimated to be 81.8 tons/year; after implementation of measures, it would be 48.6 tons/year, a total reduction of 40%. Besides reduction of point sources by means of wastewater collection and implementation of nutrient removal technology, managing agricultural phosphorus to protect water quality should become a major challenge in the Krka river basin.     

大宁河春季浮游藻类“水华”及其营养限制

报道了大宁河2004年春季和2005年春季浮游藻类的种类组成、垂直分布、数量、生物量以及C含量的调查结果，并应用多样性指数、丰富度指数和均匀性指数对其水质进行了综合评价；对大宁河蓄水后出现的富营养化现象和春季发生“水华”的原因进行了探讨，同时提出了控制水体富营养化的建议。2004年春季，藻类优势种为美丽星杆藻〖WTBX〗（Asterionella formosa）、卵形隐藻（Cryptomonas ovata）、里海小环藻（Cyclotella caspia）和新星形冠盘藻（Stephanodiscus neoastraea）；2005年春季的优势种为实球藻（Pandorina morum）、空球藻（Eudorina elegans）、里海小环藻(Cyclotella caspia)和卵形隐藻(Cryptomonas ovata)〖WTBZ〗。2004年和2005年的细胞密度、生物量和C含量分别平均为171.1×105 cells/L，12.2 mg/L，1 732.2 μg C/L和113.1×105 cells/L，10.1 mg/L，1 395.9μg C/L。对2005年春季熊猫洞采样点“水华”水进行生物测试的结果表明，P是藻类生长的限制因子。研究认为，控制大宁河沿岸带生活污水的排放量并减少由于农田地表径流所带来的营养输入是防止该河加重富营养化和发生“水华”的关键。     

Impacts of climate change on lakes and reservoirs dynamics and restoration policies

Meteorological-driven processes exert large and diverse impacts on lakes and their water quality; these impacts can be hydrologic, thermal, hydraulic, chemical, biochemical, or ecological. The impact of climate change on Lake Tahoe (California–Nevada) was investigated here as a case study of climate change effects on the physical processes occurring within lakes. The already published trends of meteorological variables were used to assess the effects of global warming on Lake Tahoe dynamics. Records from the period 1969–2002 show that Lake Tahoe has became warmer and more stable. A series of simulation years into the future (i.e., 2000–2040) was established using flows, loads, and meteorology data sets for the period 1994–2004. Results of 40-year simulations show that the lake continues to become warmer and more stable, and mixing is reduced. Possible changes in water quality because of global warming are discussed through inference, although these are not specifically simulated. Many existing problems may be exacerbated due to climate change, yet extreme uncertainty depends on the rate and magnitude of climate change. Therefore, shifts in water quality and quantity due to climate change should be integrated into contemporary planning and management in an adaptive manner, and the research and development of impact assessment methodology should focus on approaches that can handle extreme uncertainty. The general alternatives for lake management due to climate change are discussed. Depending on the specific case, further intensive research is suggested to restore lake water quality.     

Analyzing the carbon dynamics of central European forests: comparison of Biome-BGC simulations with measurements

Biogeochemical models are often used for making projections of future carbon dynamics under scenarios of global change. The aim of this study was to assess the accuracy of the process-based biogeochemical model Biome-BGC for application in central European forests from the lowlands to upper treeline as a pre-requisite for environmental impact assessments. We analyzed model behavior along an altitudinal gradient across the alpine treeline, which provided insights on the sensitivity of simulated average carbon pools to changes in environmental factors. A second set of tests included medium-term (30 years) simulations of carbon fluxes, and a third set of tests focused on daily carbon and water fluxes. Model results were compared to aboveground biomass measurements, leaf area index recordings as well as net ecosystem exchange (NEE) and actual evapotranspiration (AET) measurements. The simulated medium-term forest growth agreed well with measured data. Also daily NEE fluxes were simulated adequately in most cases. Problems were detected when simulating ecosystems close to the upper timberline (overestimation of measured growth and pool sizes), and when simulating daily AET fluxes (overestimation of measured fluxes). The results showed that future applications of Biome-BGC could benefit much from an improvement of model algorithms (e.g., the Q₁₀ model for respiration) as well as from a detailed analysis of the ecological significance of crucial parameters (e.g., the canopy water interception coefficient).     

Effect of insolation and overhead canopy on macrozoobenthos of tropical freshwater ponds

Distribution and abundance of macrozoobenthic species were investigated in open and shaded sites of tropical freshwater pond ecosystems in Kolkata. Water temperature of open sites was higher than the shaded sites but transparency value was lower at the lighted sites presumably related with the production of phytoplankton in the presence of sunlight. Diversity of species was recorded highest (26 species) along with total benthos density (5999 no/m²) at slightly illuminated open site. Mean biomass was also highest at the slightly illuminated open site. Total benthos density of macrozoobenthos was lower at the fully shaded and fully lighted sites. The greater occurrence and abundance of most macrozoobenthic species-including total benthos density and biomass at the slightly illuminated open site was probably associated with microhabitat suitability supported by moderate presence of macrophytes. Higher quality food (algae and algal detritus) and thermal suitability as well as phototactic attraction of motile epibenthic gastropods and other organisms contribute to the greater abundance and production of biomass at this site.     

丰水期赣江流域着生藻类群落结构及其与水环境因子的关系

着生藻类在水质监测与水生态健康评价中发挥着重要作用。以江西最大的河流赣江为研究对象,对赣江丰水期着生藻类群落结构及其与环境因子的关系进行研究。选取53个点位对赣江全流域进行着生藻类群落结构的调查研究,共鉴定着生藻3门42属175种,其中硅藻门有23属151种,绿藻门有9属12种,蓝藻门有10属12种。硅藻门舟形藻属为丰水期赣江流域着生藻类优势属,该属生物密度百分比为14.080%。下游着生藻类以硅藻门桥弯藻属和舟形藻属为优势属,该属生物密度百分比分别为13.088%和12.935%;中游着生藻类以硅藻门桥弯藻属为优势属,该属生物密度百分比为12.849%;上游着生藻类以硅藻门异极藻属为优势属,该属生物密度百分比达10.150%。通过蒙特卡罗显著性检验发现,赣江流域下游总氮、溶氧、叶绿素a和电导率对着生藻类有显著影响,中游主要海拔、流速、河宽和总磷对着生藻类有显著影响,上游总氮、河宽、浊度和流速对着生藻类有显著影响。将其与着生藻类群落结构进行冗余分析(RDA),结果发现影响下游着生藻类群落结构的主要水环境因子为叶绿素a和电导率,影响中游、上游着生藻类群落结构的主导水环境因子分别是海拔和总氮。可见赣江流域丰水期下游和上游的着生藻类群落可在一定程度上反映水质状况,中游着生藻类群落结构主要反映的是流域地貌因子。