遗传算法与投影寻踪模型在湿地水质综合评价中的应用

参考地表水环境质量标准和湖库营养状态评价标准,采用基于遗传算法的投影寻踪模型,计算反映湿地水体质量状况和湿地营养状态的一维投影值,直观地反映湿地水环境质量。将此方法在河北衡水湖湿地进行了实例应用,结果表明,衡水湖湿地2010年水质属于Ⅱ类,处于中度富营养状态。     

引黄调水对衡水湖湿地水质水量影响研究

为加强对衡水湖湿地的保护,对引黄调水前后衡水湖湿地的水质、水量数据进行了对比,采用Mann-Kendall检验进行了趋势分析。结果表明:引黄调水后衡水湖水位呈现上升趋势,趋势不显著,年最高水位稳定在20 m以上;综合污染指数呈现下降趋势,趋势不显著,衡水湖湿地仍处于轻度污染状态。引黄调水的入湖沙量对衡水湖生态健康也造成了一定影响。     

白洋淀水环境质量评价

由于流域人类活动和气候干旱化的影响,白洋淀水体污染与富营养化日趋严重。通过对白洋淀湖水化学成分的分析,并运用与湖泊富营养化关系最为密切的Chla、TN、TP、CODMn和SD作为评价参数,采用综合营养指数法确定湖水营养类型。湖水水质监测数据分析表明,白洋淀为重碳酸类钠组Ⅱ型水的偏碱性湖泊,综合营养指数法确定湖水为中-富营养级湖泊水体。主成分分析法结果显示,湖泊污染的主要因子是TP。借助硅藻及其组合分析了湖泊富营养化状况,发现白洋淀硅藻属种以耐营养种梅尼小环藻Cyclotellameneghiniana(20.43%)和Cyclostephanos tholiformis(25.40%)为组合特征,表明湖泊水体已处于富营养化状态,水环境状况堪忧。     

白洋淀水环境质量评价

由于流域人类活动和气候干旱化的影响,白洋淀水体污染与富营养化日趋严重。通过对白洋淀湖水化学成分的分析,并运用与湖泊富营养化关系最为密切的Chla、TN、TP、CODMn和SD作为评价参数,采用综合营养指数法确定湖水营养类型。湖水水质监测数据分析表明,白洋淀为重碳酸类钠组Ⅱ型水的偏碱性湖泊,综合营养指数法确定湖水为中-富营养级湖泊水体。主成分分析法结果显示,湖泊污染的主要因子是TP。借助硅藻及其组合分析了湖泊富营养化状况,发现白洋淀硅藻属种以耐营养种梅尼小环藻Cyclotellameneghiniana(20.43%)和Cyclostephanos tholiformis(25.40%)为组合特征,表明湖泊水体已处于富营养化状态,水环境状况堪忧。     

基于人类活动影响下衡水湖湿地生态用水安全分析

受人类活动的影响,衡水湖湿地供水水源主要靠外流域调水。在调水过程中,受沿途河道污染物的影响、引黄河水高含沙量对水质的影响以及衡水湖湿地周边工农业生产的影响,使得衡水湖湿地生态用水安全问题严峻。通过衡水湖湿地引水过程中对湿地水环境影响分析,包括供水水源分析、补水水质安全重要性分析、高含沙量对水质影响分析等,阐明衡水湖湿地供水安全中存在的问题,为恢复好保护衡水湖湿地提供科学依据。     

乐安河源区水库表层沉积硅藻与水质的相关性分析

为探究乐安河源区水库的营养程度及表层沉积硅藻对水环境的响应,选取乐安河源区段莘水库、鄣公山水库、钟吕水库、大塘坞水库以及石井水库进行研究。基于综合营养指数法(TLI)、主成分分析以及冗余分析,以水质环境为研究对象,表层沉积硅藻为研究载体,定性地分析了乐安河源区水库的营养状态以及表层沉积硅藻与水质的关系。研究结果表明：(1)乐安河源区段莘水库的水质为Ⅰ类水,处于中营养状态;石井水库严重超标,已超出Ⅴ类水标准,达到了中度富营养状态;其余水库均为Ⅲ类水,处于中营养状态;(2)硅藻群落分布特征对乐安河水环境具有良好的指示效应,如Aulancoseira grannulata等属种主要分布在水质较好、中营养程度的水体中;Cyclostephanos tholiformis等属种对乐安河源区水质较差且营养程度较高的水体指示性较强;(3)冗余分析(RDA)表明,SD、DO、TP三项水质因子较高程度的解释了当地硅藻属种组合的变化规律。     

衡水湖浮游植物多样性分析及评价

对衡水湖2016年5—10月的浮游植物多样性进行了监测分析,结果表明衡水湖水体中共有浮游植物6门57种,物种较丰富。浮游植物群落组成以绿藻门、硅藻门和蓝藻门为主,合计占总种类数的87. 72%。与其他研究者的调查成果进行对比分析,在时间上呈现出先下降后上升的趋势,可能与人类活动干扰和调水有关。浮游植物细胞密度月平均值为42. 86×106个/L,3个样点的细胞密度处于5. 84×106~125. 74×106个/L之间,各样点各月之间变化幅度较大。蓝藻门占优势,细胞密度最大,为106. 12×106个/L,基于细胞密度评价衡水湖营养状况,中营养和中富营养占比大,水体富营养化程度较高。利用Shannon-Wiener和Margalef指数计算衡水湖浮游植物多样性指数范围分别为1. 22~3. 36和0. 85~1. 85,综合评价其水质为中度污染。     

水温变化特性对衡水湖湿地生态环境影响的分析

衡水湖供水水源主要以汛期上游来水和外流域调水为主,调水时段多为每年冬季,水源供给时间相对集中。衡水湖水体水温与其他湖泊有所不同,在秋季、冬季和春季多高于一般性湖泊。通过实测资料对衡水湖内水温及气温变化规律进行分析研究,并与其他河流湖泊水体进行对比,阐明了水温变化对衡水湖湿地生态环境和水质的影响,为制定衡水湖生态系统发展规划提供科学依据。     

衡水湖湿地生物多样性功能评价

衡水湖湿地位于华北平原腹地,是北温带生物密集湿地,国际上不同候鸟南北迁徙路线的密集交汇区,众多珍稀鸟类在华北平原最理想的栖息地。根据衡水湖生物多样性调查资料,对衡水湖湿地生物多样性评价,包括物种多样性和生态系统多样性进行评价。按照湿地生物多样性评分标准,衡水湖湿地生物多样性处于一般水平。通过对衡水湖湿地生物多样性功能评价,为湿地保护提供科学依据。     

衡水湖氮磷分布现状与水体富营养化分析

依据2021—2022年衡水湖11处监测站点的水质数据，分析了衡水湖水质时空变化特征和水体营养化状态。结果表明，从时间上看，衡水湖总氮总磷浓度呈现出夏秋季节含量高、冬春季节含量低的特点；从空间上看，大库的水质好于小湖，开阔区域的水质好于湿地区域。虽然湖内植物腐烂、底泥释放等影响了水体营养盐的变化，但引调水带来污染源汇入、水生植物群落变化也对衡水湖水环境质量产生了一定的影响。     

Paleolimnological evidence of the effects of recent cultural eutrophication during the last 200 years in Lake Malawi,East Africa

To assess the long-term water quality changes in Lake Malawi, paleolimnological reconstructions of four radiometrically dated sediment cores collected in 1997/98 along a longitudinal transect of the lake were based on preserved diatom assemblages, as well as stratigraphies of organic carbon, total nitrogen, total phosphorus and biogenic silica concentrations. Population growth, deforestation and intensive agriculture, especially in the southern catchments, have accelerated soil erosion causing rivers to transport greater sediment and nutrient loads into Lake Malawi. Southern cores contain evidence of nutrient enrichment starting around 1940, as indicated by increased silica, carbon and nitrogen influxes. By 1980, increased rates of sedimentation, phosphorus influx, diatom influx, and relative abundances of eutrophic diatom taxa are attributable to accelerated nutrient enrichment accompanying soil erosion. The succession of diatoms in southern Lake Malawi begins with dominance by Aulacoseira nyassensis and Fragilaria africana, followed by a shift in 1980 towards Stephanodiscus, Cyclostephanos and Nitzschia, diatom taxa that have reduced silica requirements. Paleoecological results indicate that patterns of diatom assemblage change are not uniform lake-wide. Evidence of eutrophication extends to central Lake Malawi, but is not observable in the paleo-record from the deeper northern basin. The recent cultural eutrophication of the southern lake has impacted the biogeochemical cycling of silica, the available silica to phosphorus ratios, and the diatom communities of a large portion of Lake Malawi. These results provide a warning that eutrophication of this great lake is underway and will continue unless changes are made to current land use practices within the lake's catchment.     

Abundance Patterns of Diatoms on Cladophora in Lake Huron with Respect to a Point Source of Wastewater Treatment Plant Effluent

Epiphytic diatoms on Cladophora were collected from July to September, 1979, at various distances from a point source of municipal wastewater treatment plant effluent to Lake Huron. Diatom accumulation rates were positively related to distance from the point source. Despite higher nutrient concentrations nearest the point source, low accumulation rates of Cladophora-epiphyte assemblage biomass and epiphytic diatoms indicated moderate growth inhibition by an undetermined factor. Evaluation of epiphytic diatom population abundance and ecology plus diatom taxocene species diversity supported our conclusions. A curvilinear relationship between diatom species diversity and impacts of growth inhibition is proposed and discussed. The diatom proportion of Cladophora-epiphyte assemblage biomass was positively related to distance from the point source of sewage effluent.     

长荡湖、滆湖、竺山湾藻类功能群结构组成与环境因子的关系

为研究太湖流域上游长荡湖、滆湖、竺山湾三大典型浅水湖泊藻类功能群结构组成与环境因子的关系,基于2019年2月至2020年10月水文、水质及浮游植物数据,采用Q指数、香农-维纳多样性指数、TLI综合富营养化指数分析了3个湖泊的水质状况,采用非度量多维尺度变换(NMDS)分析了浮游植物群落结构组成特征,采用冗余分析探讨了浮游植物功能群与环境因子的关系。结果表明：长荡湖和滆湖水质整体属于轻度富营养化,竺山湾除冬季外,均属于中度富营养化;长荡湖、滆湖、竺山湾分别有浮游植物7门61属96种、8门75属129种和6门53属124种,分别划分为9、10和11个优势功能群;3个湖泊藻类功能群变化的共同环境因子是水温、高锰酸盐指数和总磷,而总氮和氮磷比对3个湖泊功能群结构变化的作用并不明显。     

基于多种方法的太湖综合水质评价比较

水污染是太湖主要的水环境问题之一,准确合理地评价太湖水质状况对该地区水环境治理具有至关重要的作用。利用单因子水质标志指数法、综合水质标志指数法、改进的综合水质标志指数法及基于污染物权重的灰色关联分析法对2004—2013年典型断面的水质进行评价,水质单项指标评价表明太湖东部及东南部污染较严重且主要污染物为NH3-N,与该地区水体富营养化现状一致,综合水质评价表明近年来太湖水质呈逐年转好的趋势;对比研究结果表明,综合水质标志指数和改进的综合水质标志指数更接近太湖水质的真实情况,其中改进的综合水质标志指数法考虑了最差污染因子对综合水质的影响,克服了单项指标算术平均带来的误差,能真实反映流域的污染状况,为水环境治理工作提供更可靠的依据。     

Hydrological alterations as the major driver on environmental change in a floodplain Lake Poyang (China): Evidence from monitoring and sediment records

Due to the lack of long-term records on shallow lake environmental change, knowledge of the processes and mechanisms behind the limnological response of many shallow floodplain lakes to hydrological alterations and nutrient loading is often limited. We examined seasonal monitoring data and a dated sediment core from Lake Poyang, a large floodplain lake located on the Yangtze floodplain in the SE China. Multivariate analysis based on contemporary data (diatoms and water quality) revealed that the seasonal changes in the diatom assemblage of the lake were correlated with water temperature and Secchi depth (SD), although the weak spatial effect was not negligible. During the dry winter season, low water temperature, low SD, and high nutrient levels, were accompanied by high abundances of planktonic Aulacoseira species along with Stephanodiscus hantzschii, a species well adapted to cold and eutrophic waters. During the summer wet season, however, when water temperature and SD were high and nutrient levels low, benthic and epiphytic diatoms, such as the genus Achnanthes, dominated. Sediment records of diatoms and geochemistry were used to estimate long-term variation in the ecological condition of the lake. During the past ~60 years, the lake has shifted from a natural hydrologically connected, oligotrophic lake dominated by benthic and epiphytic diatoms to a poorly hydrologically connected, eutrophic state driven by nutrient-tolerant planktonic and eutrophic diatoms. Furthermore, our results indicate that the proposed Poyang dam may severely affect the water quality and ecosystem of the lake by altering its seasonal hydrology.     

Validation of a diatom-based index of water quality confirms its utility in monitoring of the Lake Erie's nearshore area

We conducted a validation of the Planktonic Diatom Index (PDI) to demonstrate the utility of a water quality index for the monitoring of Lake Erie's nearshore pelagial zone. Using a large, independent dataset from the Western and Central Basins of Lake Erie for validation ensures realistic assessment of the performance of the index. Diatom-based biomonitoring allows for the inference of integrative information about water quality based on diatom species composition. The PDI is based on the assumption that phosphorus, an established proxy for eutrophication, is instrumental in the structuring of diatom communities. In this study, PDI scores and measured total phosphorus were significantly correlated (r²?=?0.34, r²?=?0.63 outliers removed). However, when samples were considered on a basin-wide basis, the PDI scores were not significantly predicted by measured total phosphorus in the Western Basin. We suggest that snapshot phosphorus measurements are less likely to represent the overall condition in the highly variable, eutrophic Western Basin. When multiple phosphorus measurements were averaged over time, the relationship with the integrative PDI scores was more apparent (r²?=?0.52). Through validation with an independent dataset, we show that the PDI is likely a monitoring tool that provides a robust assessment of water quality in the pelagial zone of the nearshore waters in Lake Erie.     

丹江口水库典型库湾及支流富营养化评价研究

为客观评价丹江口水库的水质,在库区选择了习家店和神定河2个实验区,对水体进行采样分析。分析结果表明：总体看来,丹江口水库水体富营养化状况较轻,绝大部分为中营养化状况;典型支流和库湾在特定的时段内为富营养化状况,习家店富营养化状况居中,神定河富营养化状况较严重;从年内时间分布来看,夏季水体富营养化状况均较秋季严重;从年际时间分布来看,2011年水体富营养化状况轻于2010年同期水平。     

水网连通对大东湖富营养化的影响

为定量评价水网连通对湖泊富营养化的影响,以武汉大东湖水网连通为研究对象,构建大东湖水网水生态环境数学模型,在模拟分析水网连通前后COD、TN、TP、Chl-a等富营养化评价指标变化的基础上,进一步计算和评价水网连通对各湖泊综合营养状态指数、营养状态的影响。计算结果表明:水网连通后,杨春湖、沙湖、北湖水质改善,藻类生物量减少,水体富营养程度降低;东湖、严西湖水质有一定恶化,藻类生物量增加,水体富营养程度升高;水网连通对湖泊富营养化的影响较复杂,且存在污染风险。研究成果可为水网连通工程的管理运行提供参考依据。     

Seasonal Abundance Patterns of Diatoms on Cladophora in Lake Huron

Rocks bearing Cladophora were collected from May to November 1979 at two locations near Harbor Beach, Michigan, in Lake Huron to document seasonal patterns of epiphytic diatom abundance and diatom proportion of the Cladophora-epiphyte assemblage biomass in an area receiving effluent from a municipal wastewater treatment plant. Data were examined for evidence of interactions between epiphytic diatoms and Cladophora.Cladophora first appeared in May at which time epiphytic diatoms comprised about 30% of the Cladophora-epiphytic assemblage biomass. Cladophora growth was greatest in June and July, accumulating much faster than diatoms. Peak Cladophora-epiphyte assemblage biomass was maintained from July to September. Cladophora biomass apparently decreased after August while diatom abundance increased to a September maximum. Diatoms were responsible for the sustained peak of Cladophora-epiphyte assemblage biomass as diatoms comprised over 60% of the assemblage biomass in September. The Cladophora-epiphyte assemblage collapsed by October.Low diversity of the epiphytic diatom taxocene and low diatom proportion of the Cladophora-epiphyte assemblage biomass indicated Cladophora may have outcompeted diatom epiphytes during the June-July Cladophora growth pulse. Subsequently epiphytic diatoms may have enhanced Cladophora sloughing by shading and successful nutrient competition.