Mobility of Different Phosphorus Pools in the Sediment of Lake Dianchi during Cyanobacterial Blooms

By the method of P fractionation, we examined sedimentary P fractions in Lake Dianchi before and during cyanobacterial blooms, namely in April 2004 and August 2004, respectively. In this study, the whole lake is divided into four areas to discuss P fractions in sediment and the relationship between them and water quality or the nutrient status. The results show that where the water body was much more eutrophic (higher levels of total phosphorus, total nitrogen, chlorophyll and trophic status index) in Lake Dianchi, there can be more potentially available phosphorus (BD–P and NaOH–P) and less no available phosphorus (HCl–P and residual P) in the corresponding sediments. Statistical analysis and statistical plots are used to compare the distribution of every P fraction during cyanobacterial blooms with that before cyanobacterial blooms, and the results indicate that the different P fractions had the different mobility. HCl–P and residual P were relatively stable, while NaOH–P, BD–P and NH4Cl–P were more mobile. BD–P can intensively be released from sediment to water and consequently promote cyanobacterial blooms, and at the same time the NaOH–P concentration increased in sediment, which can result from that BD–P released can be partly immobilized to NaOH–P. During cyanobacterial blooms BD–P can be as a source, but NaOH–P as a sink. Besides, total phosphorus in sediment had no significant differences between two samplings.     

典型湖泊水华特征及相关影响因素分析

通过2011-2015年对太湖、巢湖和滇池水华高发季节的连续监测，以藻类密度和水华面积为判据评价了3个湖体的水华情况及变化趋势，探讨了水华发生的主要影响因素。结果表明：太湖水华程度以"轻度水华"为主，巢湖水华程度以"轻微水华"为主，滇池水华程度以"中度水华"为主；太湖、巢湖和滇池水华规模均以"零星性水华"为主；太湖和巢湖藻类密度与水温、pH、溶解氧、总氮、总磷和高锰酸盐指数均呈显著正相关，与透明度呈显著负相关，与氨氮无显著相关性；滇池藻类密度与水温、总磷和高锰酸盐指数均呈显著正相关，与透明度和氨氮呈显著负相关，与pH、溶解氧和总氮无显著相关性。     

滇池水环境质量综合评价指标优选

在研究2000—2014年滇池流域水污染排放的时空变化、水环境质量时空变化和生态环境时空演替基础上,结合滇池目前水环境质量监测工作要求,采用模型计算、指标特性分析、专家调查等方法,筛选出36个评价指标,分别表征滇池水环境质量的物理、化学、生物、营养、重金属、有机污染等特性,将滇池湖体4个监测点位优选出的评价指标监测数据输入水生态健康评价系统。结果表明,优选指标和评价体系能全面、准确、宏观地反映滇池水环境质量状况。将滇池评价指标由现有的94个压缩至36个,极大节省人力、物力,且更符合滇池水环境特点。     

滇池水环境质量综合评价方法

研究了2000—2017年滇池水环境质量时空变化和生态环境时空演替规律,结合滇池目前水环境质量监测工作要求,利用以往研究成果筛选出的36个评价指标,采用层次分析法,构建滇池水生态健康评价方法模型,得出滇池水生态健康评价标准,输入滇池湖体2011—2017年4个监测点位相关指标监测数据进行方法验证。验证结果表明,建立的评价方法能较为全面、准确、宏观地反映滇池水环境质量状况,与现有综合评价方法相比,能综合反映现有评价方法结果,且具有宏观、全面等优点,能很好地响应生物多样性变化,服务滇池的治理工作。     

Monitoring of potentially toxic cyanobacteria using an online multi-probe in drinking water sources

Toxic cyanobacteria threaten the water quality of drinking water sources across the globe. Two such water bodies in Canada (a reservoir on the Yamaska River and a bay of Lake Champlain in Québec) were monitored using a YSI 6600 V2-4 (YSI, Yellow Springs, Ohio, USA) submersible multi-probe measuring in vivo phycocyanin (PC) and chlorophyll-a (Chl-a) fluorescence, pH, dissolved oxygen, conductivity, temperature, and turbidity in parallel. The linearity of the in vivo fluorescence PC and Chl-a probe measurements were validated in the laboratory with Microcystis aeruginosa (r(2) = 0.96 and r(2) = 0.82 respectively). Under environmental conditions, in vivo PC fluorescence was strongly correlated with extracted PC (r = 0.79) while in vivo Chl-a fluorescence had a weaker relationship with extracted Chl-a (r = 0.23). Multiple regression analysis revealed significant correlations between extracted Chl-a, extracted PC and cyanobacterial biovolume and in vivo fluorescence parameters measured by the sensors (i.e. turbidity and pH). This information will help water authorities select the in vivo parameters that are the most useful indicators for monitoring cyanobacteria. Despite highly toxic cyanobacterial bloom development 10 m from the drinking water treatment plant's (DWTP) intake on several sampling dates, low in vivo PC fluorescence, cyanobacterial biovolume, and microcystin concentrations were detected in the plant's untreated water. The reservoir's hydrodynamics appear to have prevented the transport of toxins and cells into the DWTP which would have deteriorated the water quality. The multi-probe readings and toxin analyses provided critical evidence that the DWTP's untreated water was unaffected by the toxic cyanobacterial blooms present in its source water.     

Spatiotemporal distribution pattern of cyanobacteria community and its relationship with the environmental factors in Hongze Lake,China

Hongze Lake, located in the east route of the South-to-North Water Diversion Project (SNWDP), is a potential drinking water source for the residents along this water diversion project. Based on a monthly sampling at 11 stations in three regions of Hongze Lake, the spatiotemporal distribution pattern of cyanobacteria community was comprehensively investigated from March 2011 to February 2013. A total of 23 cyanobacterial species which belong to 16 genera were identified, and Microcystis was the most predominant cyanobacterial genus mainly composed of Microcystis wesenbergii in Hongze Lake. The cyanobacterial abundance ranged from 0 to 2.6?×?10⁷ cells/L, and the average cyanobacteria abundance of Northern region was significantly higher than those of Western region and Eastern region in the 2-year study. The total cyanobacteria abundance and the Microcystis abundance both took on a similar seasonal regularity in the three regions. The results of correlation analysis indicated that Microcystis abundance was correlated with water temperature, chemical oxygen demand (COD)_Mn, nitrate (NO₃-N), and total nitrogen (TN)/total phosphorus (TP) mass ratio, among which water temperature had the highest correlation coefficient. In summer, cyanobacteria blooms may take place under suitable environmental conditions at some special areas in Hongze Lake, especially where the concurrence of slow water exchange and steady wind direction exists.     

Variations in Epilimnion Thickness in Small Boreal Shield Lakes: Relationships with Transparency, Weather and Acidification

We used multiple linear regression analysis to investigate relationships between late-summer epilimnion thickness, transparency, lake area, acidity and summer weather conditions in a large ($n = 116$) multi-year data set for 9 small Boreal Shield lakes. Dissolved organic carbon (DOC) was the best individual predictor of late summer epilimnion thickness ($r^{2} = 0.69$). Total chlorophyll~$a$, the number of days between ice-out and late-summer stratification, and lake area collectively explained an additional 14% of the variation in epilimnion thickness. The three attributes of summer weather that we examined, mean daily temperature, mean daily wind speed, and mean daily hours of bright sunshine, did not add to the predictive ability of our regression model. Lake acidity also did not add directly to the predictive ability of the model, likely because DOC concentrations already reflected the effects of pH. Our study supports an increasing body of evidence indicating that the dominant effects of climate change on lake thermal structure in small lakes will be through effects on processes that affect lake transparency.     

太湖蓝藻水华暴发程度年度预测

近年来,尽管太湖主要水质指标有所改善,但蓝藻水华暴发的频次和面积并未明显减少.为了探讨太湖蓝藻水华暴发的环境驱动因子,统计了2012—2020年历年4—10月预警期间的太湖蓝藻水华发生规模与频次,结合同步浮标自动监测数据和实验室分析数据,构建了蓝藻水华预测模型.以太湖蓝藻水华综合指数(Ic)表征蓝藻水华强度,并通过Ic...     

特殊风场条件对太湖蓝藻水华迁移的影响研究

在高温、微风气象条件下,适宜蓝藻水华形成。在特殊非均一风场的驱动下,太湖蓝藻水华迁移过程与被均匀风场驱动有所不同。选取太湖典型风向进行分析,并采用三维水动力水质模型对表面非均一风场条件下的风生流流场及水质进行模拟,结果表明,在特殊非均一风场的驱动下,当太湖蓝藻浓度较高时,容易在西部湖区特别在竺山湖、梅梁湾湾内、岸边及湾口聚集,形成水华暴发,这有助于研究太湖污染物及蓝藻水华的输移及空间分布和机理。     

滇池近20年水环境变化趋势与影响因素分析

利用2001—2020年滇池水质监测数据,研究其水环境时空变化特征。结果表明：滇池水质呈现波动变化趋势,TN波动区间较大,呈现雨季＜旱季的变化趋势。TP年内变化3—6月呈现增长趋势,空间上滇池北部TP值整体较高。Chl-a年内变化7—10月出现明显提升。IMn波动区间较大,空间上滇池南部呈现IMn值较高且稳定。NH3-N年内2—11月整体呈现连续下降趋势。2001—2020年滇池TLI整体呈现波动降低;空间上呈现由北向南递减,草海区域富营养化较为严重。滇池Chl-a与TN、TP、水温、pH值及降雨量呈现正相关性,与水位和透明度呈现负相关性。     

滇池流域水环境综合管理技术支撑平台构建研究

滇池流域水环境综合管理技术支撑平台以实现水环境数据信息化、支撑多元化、管理智能化为目标,集成水环境多元数据采集传输、融合共享及动态表征技术,突破高原湖泊流域多目标复杂环境综合管理决策控制技术,构建"数据中心-业务系统-信息发布"为主线的综合管理平台,其以水环境数据中心为支撑,以水环境信息系统与水环境专家决策支持系统为核心,以水环境信息发布系统为共享交换媒介,为流域管理提供监控预警、总量控制、预测预报、项目评估及应急决策等技术服务,有效支撑滇池流域水环境监控预警和综合管理。     

Detection of microcystins in Pamvotis lake water and assessment of cyanobacterial bloom toxicity

Lake Pamvotis is a shallow, eutrophic Mediterranean lake with ecological significance. This paper deals with the evaluation of cyanobacterial toxicity in Lake Pamvotis. ELISA and HPLC revealed the presence of significant amounts of MCYST-LR. Danio rerio bioassay confirmed the toxic nature of the bloom. Cyanobacterial extracts had adverse toxic effects on development of D. rerio. Also, it was shown that cyanobacterial extracts containing environmentally detected concentrations of MCYST can cause reduced survival rate of fish species. The results clearly indicate that cyanobacterial blooms in Lake Pamvotis may be regarded as human and fish health hazard. Continuous monitoring of the lake is suggested, in order to prevent future possible intoxications.     

Spatial and temporal variability in the relationship between cyanobacterial biomass and microcystins

The increasing incidence of toxic cyanobacterial blooms, together with the difficulties to reliably predict cyanobacterial toxin (e.g. microcystins) concentration, has created the need to assess the predictive ability and variability of the cyanobacterial biomass–microcystin relationship, which is currently used to assess the risk to human and ecosystems health. To achieve this aim, we assessed the relationship between cyanobacterial biomass and microcystin concentration on a spatiotemporal scale by quantifying the concentration of cyanobacterial biomass and microcystin in eight lakes over 9 months. On both a temporal and spatial scale, the variability of microcystin concentration exceeded that of cyanobacterial biomass by up to four times. The relationship between cyanobacterial biomass and microcystin was weak and site specific. The variability of cyanobacterial biomass only explained 25 % of the variability in total microcystin concentration and 7 % of the variability of cellular microcystin concentration. Although a significant correlation does not always imply real cause, the results of multiple linear regression analysis suggest that the variability of cyanobacterial biomass and cellular microcystin concentration is influenced by salinity and total phosphorus, respectively. The weak cyanobacterial biomass–microcystin relationship, coupled with the fact that microcystin was present in concentrations exceeding the WHO drinking water guidelines (1 μg?L^?1) in most of the collected samples, emphasizes the high risk of error connected to the traditional indirect microcystin risk assessment method.     

基于气象条件的太湖湖泛预警研究

2007年5月与2008年5月太湖水域产生的湖泛主要是由蓝藻水华引发的,但是蓝藻水华单纯地在湖湾或岸边浅水区大量堆积并不一定引发湖泛。研究发现,2007年5月与2008年5月的湖泛现象存在相同的触发机制:3d以上时间维持高温(平均气温大于20℃),微风(平均风速小于4m/s),风向基本一致(风向平均绝对偏差小于20°);其后,冷空气过境使得风速短时增大,风向调转180°左右,气温迅速降低,并且这种气象条件持续1d以上。在此研究基础上,给出了切实可行的太湖湖泛预警方案。     

2015年以来太湖总磷升高原因的研究

对2015年以来的太湖TP变化趋势进行了研究,并对TP升高原因进行了分析。结果表明,2015—2019年,太湖TP浓度由0.059 mg/L上升至0.079 mg/L,涨幅34.1%。太湖TP上升的原因可能为:随入湖大量泥沙的带入而累积;东太湖水生植被覆盖面积急剧下降,使得湖体TP上升幅度明显;太湖磷营养盐浓度影响着蓝藻水华爆发的强度,蓝藻水华加快了湖体磷循环;夏季受台风天气影响,风浪较大的条件下造成底泥的再悬浮与释放而影响水质。     

洞庭湖区一次重度空气污染过程成因分析

利用AQI和PM_(2. 5)质量浓度、地面气象要素、NCEP、ERSST_V3、GBL等资料,对2016年12月29日至2017年1月5日洞庭湖区一次重度空气污染过程成因进行了分析。结果表明,静稳天气形势下的累积效应和本地持续升温、降压、增湿、小风导致污染物浓度不断增加。本地风速与雨量对污染物浓度产生显著影响。降温前风速明显加大,有利于污染物快速扩散。湿度增加有利于污染物吸湿性增长,但高湿易引起降水有利于污染物的湿清除。此次重度空气污染过程中大气稳定度为中性或稳定,14:00混合层高度逐渐降低且重度空气污染日降至100 m以下。污染物空间分布与主导风向和污染通道密切相关。气流后向轨迹分析表明,洞庭湖区各地气流来源和影响路径差异明显,且存在大范围区域性同步污染现象。北方外来污染源是洞庭湖区重要的污染面源,本地工业污染排放点源和地理条件也是洞庭湖区空气污染物空间分布差异的重要因素。     

太湖蓝藻预警采样点位布设与采样层次的研究

蓝藻水华的聚集和分布与气象条件有着密切的关系.根据近几年蓝藻预警监测及科研的实践,分析了风向对蓝藻迁移的影响,以及不同深度的藻密度变化情况.以此为依据,对太湖蓝藻监测时采样点位布设与采样层次选择的方案进行了比较研究,并提出了优化方案,为环太湖地区的相关部门更好地开展蓝藻预警监测工作提供了科学依据.     

杭州市大气细颗粒物PM_(2.5)中多环芳烃含量特征研究

按季节对杭州市大气细颗粒物PM2.5中16种多环芳烃(PAHs)的含量在2006年进行了为期一年(样本数n=47)的测定分析.研究表明,杭州市大气PM2.5中PAHs总浓度为40.66ng/m3,以中环或高环为主,分别占总PAHs的32.23%和47.6%;云栖点位(位于风景名胜区内)PM2.5中PAHs浓度高于朝晖点位(位于商业居民混合区);季节变化呈现春季高,秋季低的特点;PM2.5中苯并[a]芘等效毒性(BEQ)为4.50;PM2.5中PAHs的来源不是单一的.     

太湖蓝藻水华暴发主要特征初析

太湖水体富营养化加剧引起了多方面的关注,针对近年实际监测结果,结合历年流域水环境质量的变化,初步归纳了当前太湖蓝藻水华暴发的地域特征、时间周期特点及主要水质指标的变化规律,总结了太湖蓝藻水华的暴发呈多峰形状态.2007年太湖沙渚水源地藻类生物量的两峰三阶段的特征进一步表明,太湖蓝藻水华的暴发进入了高频期.     

2015年新疆阿克苏市沙尘污染与气象因素关系的分析

应用阿克苏市国家基准站及2个环保局监测站2015年大风沙尘天气过程前后PM10浓度变化及其与污染源、NECP全球再分析资料、风、监测站周边环境等关系进行分析.结果表明,阿克苏市春季沙尘天气的首要污染物均为PM10,PM10的变化曲线呈正态分布,春季中度及以上污染日均出现在污染日当日或次日.造成阿克苏市沙尘天气污染源分本地型、外来型以及二者共同影响型三种.本地型沙尘污染强度取决于北风风速大小及强风持续时间,PM10浓度变化与风速呈正相关.而外来型污染多发生在本地型沙尘天气之后,"东灌"冷空气裹挟沙尘进入南疆盆地,造成地面加压,浮尘天气造成PM10浓度增大,并持续数天.总结出沙尘天气污染预警的几个必要条件,后续在地区环保局、县局监测站建立的情况下,为分析阿克苏地区"八县一市"污染物与气象因素的关系提供借鉴,同时为实际的空气质量预警提供参考.