A comparison of zooplankton assemblages in Nansi Lake and Hongze Lake,potential influences of the East Route of the South-to-North Water Transfer Project,China

Nansi Lake and Hongze Lake are both water storage lakes along the East Route of the South-to-North Water Transfer project(ESNT).Frequent changes in hydrologic properties are responsible factors for controlling the zooplankton community assemblages in both lakes,so we studied the possible influence of water transfer and environmental factors on zooplankton community structure and abundance.Zooplankton assemblages were investigated seasonally for one year in both lakes;a total of 133 and 122 zooplankton taxa were identified in Nansi Lake and Hongze Lake,respectively.The most dominant rotifer species were littoral,e.g.,Keratella tecta,Keratella valga and Lecane lunaris in Nansi Lake and Brachionus angularis,Brachionus forficula and Polyarthra vulgaris in Hongze Lake.Comparatively,Nansi Lake had a higher Shannon-Wiener diversity index value(5.13),while Hongze Lake had a higher species richness index(4.21).The average number of zooplankton across seasons in Nansi Lake(protozoa:774±63 ind./L,rotifers:4817±212 ind./L,cladocerans:896±14 ind./L,copepod:435±42 ind./L)was comparatively lower than Hongze Lake(protozoa:1238±63 ind./L,rotifers:6576±112 ind./L,cladocerans:1013±20 ind./L,copepod:534±25 ind./L).Canonical correspondence analysis identified differing environmental gradients that were most responsible for influencing zooplankton communities in the two lakes(Hongze Lake:NH4-N,total nitrogen,transparency and pH;Nansi:pH,temperature and total phosphorus).Frequent changes related to water transfer in lakes favoured the diversity of rotifers and protozoa communities.Zooplankton habitat preference,changes in community structure and opportunistic peaks and extinction of certain taxa were also observed in the study lakes.

The Construction and Study of Nansi Lake Water Environment Management Platform Based on WebGIS

According to targets and needs of Nansi Lake water eco-environment management, we took the advantages that WebGIS serves as an overall solution, combined characteristic of SuperMap IS.net WebGIS service platform and adopted the B/S three-tier distributed architecture to put forward the overall design idea, function structure and structure scheme of Nansihu water eco-environment assessment and management WebGIS. Subsequently, we used the C# programming language to carry out the concrete development job, and figured out a scheme to store and disseminate space data and attributes data. Ultimately, with the aid of SuperMap’s large-scale spatial database engine SDX+, the system has realized a lot of functions such as spatial information search, hydrology and water quality information inquiry and statistics, water environment quality assessment, lake eutrophication assessment, embodying the visualization of systems analysis sufficiently. The system has been mainly studied and developed in the technology of lake eco-environment management, and also provided an intuitionistic, universal, convenient and reliable management tool for Nansihu water eco-environment management.

Economic Development Mode and Countermeasure Research on the Nansi Lake Drainage Area Based on Circular Economy

Firstly,it is pointed out that circular economy should be vigorously developed in the Nansi Lake Drainage Area,and the connotation of circular economy is expounded.Then,problems in developing circular economy in Nansi Lake Drainage Area are analyzed from the aspects of agriculture,industrial enterprises,and waste utilization.Finally,combining with the four modes of peasant household,enterprise,region and society in the development of circular economy,corresponding countermeasures are put forward for the circular economy in Nansi Lake Drainage Area,such as establishing the government guidance mechanism for big agriculture circular economy in Nansi Lake Drainage Area,constructing incentive systems for industrial enterprises adopting circular economy in Nansi Lake Drainage Area,adjusting the industrial structure of Nansi Lake Drainage Area,and optimizing the energy consumption structure.

GIS and L-THIA Based Analysis on Variations of Non-point Pollution in Nansi Lake Basin,China

Non-point source （NPS） pollution is the main threat to regional water quality, and the estimation of NPS pollution load has become an important task for NPS pollution control in China. Combined with geographical information system （GIS）, the long. term hydrologic impact assessment （L-THIA） model was used to evaluate the temporal.spatial changes of chemical oxygen demand （COD）, total nitrogen （TN） and total phosphorus （TP） in Nansi Lake basin from 2000 to 2010. The results show： 1 ） the estimated COD, TN and TP loads in 2010 are 260017.5, 111607. 7 and 6372.0 t with the relative errors of 2.1%, 2. 0 % and - 8.8 % respectively, and more than 90% concentrated in the raining period from June to September; 2） cultivated land and construction land take up more than 80% of the whole Nansi Lake basin, and the proportions of the three kinds of NPS pollution loads coming from cultivated land and construction land are more than 98%; 3 ） during 2000- 2010, the COD, TN and TP loads increase by 8801. 6, 180.3 and 71.9 t respectively, and become the main impact factors on the water quality of Nansi Lake.

Analysis of Land Use Changes in the Watershed of Nansi Lake,Shandong Province

Change of land use is related to regional food security and ecological security.This study analyzed structural changes,quantity changes and spatial changes of land resource utilization in the watershed of the Nansi Lake,Shandong Province from 2000 to 2012 on the basis of land use investigation data and relevant socio-economic data in the study period.It is to disclose the problems in the utilization of local land resources,and provide scientific support for the scientific management of land resources and sustainable development of social economy.

Human Influence on Heavy Metal Distribution in the Upper Lake Nansi Sediments, Shandong Province, China

Core and surface sediment samples were collected from three sub-lakes (Lake Nanyang, Lake Dushan and Lake Zhaoyang) in the Lake Nansi Basin, Shandong Province. In order to reveal the characteristics of spatial and historical distribution of heavy metals in different sub-lakes of the Upper Lake Nansi, heavy metal (As, Cr, Cu, Hg, K, Mn, Ni, Pb, Zn, Al, Fe, Ti and V) concentrations of sediment samples were investigated. Based on the activity of 137Cs in the sediments, the modern accumulation rate of Lake Nansi sediments is 3.5 mm/a. Our results show that the whole Upper Lake Nansi has been already polluted by heavy metals, among which Lake Nanyang has been polluted seriously by mercury, as well as by lead and arsenic, while Lake Dushan has been most seriously polluted by lead and arsenic. Historical variation of heavy metal (Cr, Cu, K, Ni, Zn, Al, Fe, Ti and V) concentrations shows an abrupt shift in 1962, resulting in a division of two periods: from 1957 to 1962 when metal enrichment increased with time, and from 1962 to 2000 when it decreased with time, while that of some anthropogenic elements such as Hg, Pb and Mn tend to increase toward the surface. However, the variation trend of As in the sediments is different from that of Hg, Pb and Mn, with its maximum value appearing in 1982. Since 1982 the concentrations of As have decreased due to the forbidden use of arsenite pesticides. This variation trend revealed changes in manner of human activity (coal combustion, waste discharges from both industries and urban sewage) within the catchment during different periods.

调水影响下湖泊流域水资源多尺度演变与安全调控

针对大规模调水输入等强烈人类活动影响下的湖泊流域水文循环剧烈变化威胁湖泊流域水安全的问题,开展了“调水输入影响下湖泊流域水资源多尺度演变与安全调控关键技术”研究。主要内容包括:进行典型湖泊及其主要入湖河流水量、水质、水生态多要素同步监测,揭示了胁迫湖泊流域水资源安全的关键因子,阐明下垫面变化下水文水动力多要素耦合机制,辨识了多水源交互作用下湖泊水质和蓝藻的响应关系,提出了水资源水环境水生态协调的控制阈值与实现条件;创新了水资源-经济社会-生态环境互馈模拟技术、水资源供用耗排补全过程模拟技术、大型复杂水体“0-1”结构洪水演进模拟技术、河网洪水行为模拟技术,研发了湖泊流域水资源多尺度模拟调控模型,突破了多过程耦合、尺度相容、非均匀性协调等模型构建的难题。依托成果创建了湖泊流域水资源安全智慧管控平台,在国家、流域、省、市不同层级的防洪、排涝与水资源管理中实现了体系化应用,为南四湖、太湖、巢湖等多个湖泊流域管理与多项重大工程的建设和规划编制、河湖管理科技进步提供了支撑。

南四湖消落带底泥中磷及微生物群落结构研究

研究不同频率干湿交替条件下,南四湖消落带底泥磷形态变化及其与生物群落结构的关联性,可为维持南四湖消落带水生态系统健康及保障南四湖水质提供技术支持。文章模拟了南四湖消落带底泥不同频率干湿交替过程,通过高通量测序技术分析了底泥生物群落的变化特征。结果表明:在干湿交替过程中,底泥总磷、无机磷呈降低趋势,而有机磷基本保持不变;不同干湿交替过程中消落带底泥微生物群落结构比较稳定,但群落丰度变化显著;频繁干湿交替不利于消落带底泥保持微生物多样性;消落带底泥中蓝藻门(Cyanobacteria)和疣微菌门(Verrucomicrobiota)与底泥中NaOH-P呈显著负相关,变形菌门(Proteobacteria)与总磷则呈正相关。

基于集成学习的内陆水体叶绿素a浓度反演

利用卫星数据监测内陆或水质状态,对生态决策具有重要意义。基于具有高时空分辨率的哨兵二号卫星数据,联合2种集成学习算法反演山东省南四湖叶绿素a(Chla)浓度,结果表明经遥感反射率校正后的哨兵二号数据更加适用于水质反演。XGBoost模型在五折交叉验证反演结果上表现最优(R^(2)=0.732 5,RMSE=9.168 1μg/L),反演结果更符合实际情况。因此,使用该模型反演南四湖叶绿素a浓度,能较好地掌握其时空变化情况,对其他区域类似研究可提供一定参考。

数字孪生技术助力南四湖防洪调度与二级坝工程管理

数字孪生建设是“十四五”期间推进智慧水利建设的重要内容之一,为提高南四湖流域防洪调度水平和二级坝工程运行管理能力,采用南四湖防洪调度、二级坝泄量纠偏及调度仿真等关键技术,建立和完善二级坝感知体系,提升算力能力建设;建设数据底板,加强算据能力建设;研发多种模型,智能展示数据成果;开发具有“四预”功能的防洪调度和水闸综合管理业务应用等系统。系统的建成可全面提高南四湖防洪调度及二级坝工程管理安全运行管理水平,为后续数字孪生沂沭泗建设提供经验样本和技术模板。

山东南四湖菹草时空分布及其对水环境的影响

为了解南四湖菹草种群的变化特征及其对水环境的影响规律,利用遥感影像技术监测南四湖2017—2022年菹草时空分布格局,从透明度(SD)、溶解氧(DO)、化学需氧量(COD)、总氮(TN)、总磷(TP)、叶绿素a(Chla)6个指标分析菹草在不同生长史阶段对水环境的影响。结果表明:2017—2020年南四湖菹草面积一直处于增长趋势,从2017年的208.65km^(2)快速增长到2020年的311.81km^(2),增长率达49.44%;2021年菹草面积有所减少,2022年较2021年有所增加。菹草在整个生长周期内对水环境产生双重影响,菹草生长过程中吸收水体中的N、P等营养盐,增加水体DO,有利于改善水体理化性质;但菹草死亡腐败后,分解产生较多有机质,使得COD浓度升高,同时消耗水中DO、Chla含量逐渐增加,导致水体透明度下降,引起水质恶化。为保障水质安全,应加大菹草综合治理和资源化利用研究,合理控制菹草的生长规模。

极端干旱对南四湖湿地景观影响的遥感分析

在气候变化加剧背景下,研究湿地的干旱响应特征具有重要意义。以草型湖泊南四湖2002年发生的极端干旱事件为例,基于干旱年及正常年Landsat遥感数据、长时序气象数据、帕默尔干旱指数(PDSI)数据等,计算南四湖归一化植被指数(NDVI)、修正的归一化水体指数(MNDWI)、植被覆盖度(FVC),并分析了干旱前后的景观指数变化特征,包括斑块数量(NP)、斑块密度(PD)。结果表明:1)干旱年降水的显著偏少及气温的异常偏高是导致这次干旱事件的主因;2)干旱年南四湖水域面积大幅减少,并在10月出现干湖现象;3)湿地植被特征与干旱程度显著相关(P<0.05)。随着干旱的加重,植被面积及NDVI、FVC呈现先增后减的趋势,在8月达到最大后开始减小;4)相比正常年份,干旱年湿地景观特征差异显著。干旱年水体面积显著下降,水体斑块数量增加912个、斑块密度增加15.47,水体景观趋于破碎化,而植被面积显著增加,植被景观破碎化降低。研究可为湖泊湿地的气候适应性管理提供一定科学指导。

基于稳定同位素贝叶斯混合模型的南四湖水量来源定量解析

为定量解析南四湖水源组成,厘清本地水与外调水的关系,精准保护湖泊水资源,本文建立了基于氢氧稳定同位素的贝叶斯混合模型,分析比较南水北调东线运行后调水期和非调水期不同水源对南四湖湖区的贡献比例及季节特征。结果表明:(1)流域降雨受到一定程度局地蒸发的影响,夏季受海洋蒸发水汽的影响;(2)南四湖地下水、大气降水、入湖河流和外调水等不同水源对湖区水体的贡献比例受南水北调东线工程运行影响较大,调水期分别为5.4%、8.7%、31.2%和54.7%,外调水贡献比例最高;非调水期分别为22.9%、53.0%、6.7%和17.4%,大气降水贡献比例最高,入湖河流贡献相对较少。(3)南水北调东线调水实施后,调水期的外调水量对湖区的贡献占绝对优势,表明调水对南四湖水量变化发挥了重要作用,调水活动逐渐取代自然因素成为流域水量变化的主要驱动因子。

南四湖沉积物抗生素的组成特征和环境风险

为保障南四湖生态安全和周边居民健康,在汛后和汛前对南四湖沉积物中大环内酯类、四环素类、喹诺酮类、β-内酰胺类、磺胺类和氯霉素类抗生素进行测定,分析其组成特征,并评估其潜在的环境风险。结果表明:抗生素总含量在2.72~276.07 ng·g^(-1)之间,平均含量较高的有喹诺酮类的氧氟沙星(11.67 ng·g^(-1))、恩诺沙星(4.96 ng·g^(-1))、环丙沙星(3.80 ng·g^(-1))、诺氟沙星(3.60 ng·g^(-1))和四环素类的氧四环素(6.40 ng·g^(-1))、金霉素(2.34 ng·g^(-1))。此外,大环内酯类的一些抗生素检出率较高,其中洁霉素和罗红霉素的检出率为100%。抗生素组成在汛后和汛前具有显著差异(Adonis test,P<0.01),汛后抗生素的含量和种类数(48.21 ng·g^(-1),27种)均高于汛前(32.08 ng·g^(-1),23种);而上级湖和下级湖间的抗生素组成无显著差异,但在不同采样位点间变化较大。风险熵值分析表明,氧氟沙星、环丙沙星、氧四环素和洁霉素同时具有较高的生态风险和抗生素抗性发展风险,且一些低或无生态风险的抗生素(如诺氟沙星和氯霉素)也可能产生较高的抗生素抗性发展风险。

Variation of cyanobacteria with different environmental conditions in Nansi Lake,China

Nansi Lake is located on the east line of the South-to-North Water Diversion Project in China. A comprehensive study was carried out to investigate the spatial and temporal distribution of cyanobacteria in the lake from June 2008 to May 2011 based on monthly sample monitoring from five stations. The effect of environmental factors on cyanobacterial abundance was also evaluated. The eyanobaeterial community contained 15 genera and 23 species. The cyanobacterial abundance of each monitoring station ranged from 0 to 1.53x 107 cells/L with an average of 1.45~ 106 cells/L, which accounted for 11.66% of the total phytoplankton abundance. The dominant species of cyanobacteria were Pseudanabaena （32.94%） and Merismopedia （19.85%）, not the bloom-forming algae such as Microcystis and Anabaena. In addition, the cyanobacterial community structure and water quality variables changed substantially over the survey period. Redundancy analysis （RDA） suggested that temperature and phosphorus were important environmental factors that affected cyanobacteria. Temperature was the most important factor affecting cyanobacterial abundance. The effect of phosphorus on cyanobacterial abundance was more notable in warm periods than in periods with low temperature.

EFFECTS OF AQUATIC VEGETATION ON FLOW IN THE NANSI LAKE AND ITS FLOW VELOCITY MODELING

Aquatic vegetation has significant effects on flow in waters. In this article, four types of water areas were analyzed according to the field survey on water depth and vegetation in the Nansi Lake for the East Line Project of Water Transfer from South to North in China （WTSNC）. The depth-averaged 2-D hydrodynamic models with and without consideration of the effects of aquatic vegetation on flow were established to simulate flow fields in vegetated and non-vegetated zones in the Nansi Lake. With the established models, flow fields were predicted under the conditions of water transfer from south to north. The results indicate that when the drag force term exerted by aquatic vegetation is considered, the computed velocities agree well with the measured data, whereas as the drag term is taken into account, the computed velocities are obviously larger than the measured data in the vegetated zone and considerably smaller in the non-vegetated zone, and the error range between the two velocities is large if this problem is dealt with the method of increasing the roughness coefficient of the lake-bed to reflect the vegetation drag force. In addition, it is demonstrated that the emerged vegetation exerts larger effects on flow than submerged vegetation comparing the results in the Emerged Vegetation （reed） Zone （EVZ） and the Submerged Vegetation Zone （SVZ）.

Phosphorus release potential and pollution characteristics of sediment in downstream Nansi Lake, China

The research aimed to evaluate present and potential phosphorous pollution due to high sedimentary phosphorus load and release from sediment, when external phosphorus was reduced in downstream Nansi Lake. Pollution load of the sediment and overlying water was investigated. Kinetics and isotherms of adsorption/release of sedimentary phosphorus were studied to determine equilibrium phosphate concentration （EPCo） and release potential. Kinetics of phosphorus adsorption on sediment and release from sediment were well described by both the pseudo-first-order rate equation and the pseudo-second- order rate equation, but more appropriate to the pseudo- second-order rate equation with the adsorption/release capacity more close to the measured values, suggesting that the processes were chemically rate controlled and dependent on adsorption capacity. Soluble reactive phosphorus （SRP） sorption isotherms on sediment were best fitted by the modified Langmuir model indicating a monolayer adsorption. By comparing EPC0 and SRP of water, the status （adsorption, releasing or in equilibrium） of sediment phosphorus could be determined. The sediments at site S l, S3, S4, S5, and S7 where the EPC0s were greater than the SRPs, had a potential to release phosphorus into the water column. However, those sediments at S9, S10, and S 12, where the EPC0s were approximately equal to the SRPs, were in impermanent equilibrium with overlying water in status of phosphorus, the sediments can be likely to release phosphorus to the water column once the equilibrium was broken. Therefore, sedimentary phos- phorus can be a secondary pollution source in downstream Nansi Lake.

冬季调水期南四湖水体温室气体溶存浓度及其影响因素

为了解冬季调水期南四湖表层水中温室气体的溶存浓度及其排放通量,采集南四湖各湖区和主要入湖河流的河口区表层水及气体样品,分析了水体的理化指标以及CO_(2)、CH_(4)和N_(2)O的溶存浓度,采用薄边界层扩散模型法估算了水—气界面排放通量,并探讨了影响调水期南四湖温室气体溶存浓度的主要因子.结果表明,调水期南四湖表层水中N_(2)O、CH_(4)和CO_(2)浓度分别为(23.0±6.13)nmol·L^(-1)、(0.15±0.10)μmol·L^(-1)和(52.4±11.4)μmol·L^(-1),均处于高度过饱和状态,排放通量分别为(0.22±0.18)μmol·m^(-2)·h^(-1)、(3.95±2.73)μmol·m^(-2)·h^(-1)和(658±336)μmol·m^(-2)·h^(-1);浓度和排放通量多与冬季其他湖泊相当,但低于平原河网.各温室气体浓度、饱和度和排放通量整体呈现自上级湖向下级湖降低的趋势,且在河口区和二级坝附近水域浓度较高,同时N_(2)O和CO_(2)浓度在微山湖湖心区出现带状高值区,而CH_(4)相对较低.各温室气体浓度与水质参数间具有一定的相关性,其中,N_(2)O浓度与NO_(3)^(-)、NO_(2)^(-)浓度呈显著正相关,CH_(4)与TN呈显著负相关,CO_(2)与pH、SD呈显著负相关,与DOC呈显著正相关,反映了水质对温室气体溶存浓度的影响.研究结果为评估调蓄湖泊在调水期对大气温室气体的影响提供了基础数据支撑.

基于水体交换能力的调水工程对底栖动物群落影响研究

水文条件的改变会引起水生态系统的波动变化,大型调水工程的实施会改变水生生物群落结构。本研究分别调研了南四湖和东平湖在调水工程实施前后一段时间的大型底栖动物群落结构,模拟分析了调水工程引起的湖泊水龄变化特征,从水体交换能力的角度探讨了大型调水工程对湖泊中大型底栖动物群落的影响。结果显示,调水工程运行一段时间后,东平湖中大型底栖动物群落在年尺度上从由小体型的水生昆虫类主导转变为由大体型的软体动物主导,南四湖中软体动物的优势在调水工程实施之后更加凸显。在季节尺度上,软体动物占比通常在调水期(非雨季)减小,而在非调水期(雨季)增大。调水工程的实施改变了湖泊水动力场特征,在年尺度上增强了湖泊水体交换能力,调水入流与入湖径流的叠加使湖泊水体的高流速时间变长,这不利于小体型物种稳定生长,进而导致在年尺度上大体型软体动物的占比逐渐增大。此外,调水工程的实施主要是提升了非雨季湖泊的水体交换能力,但增加调水后的非雨季湖泊水体交换能力仍然小于雨季,这也导致软体动物占比在调水工程实施前后均呈现在雨季减小在非雨季增加的规律。

南水北调工程对南四湖下级湖水体交换特征影响研究

【目的】南水北调东线工程以南四湖为输水通道,工程运行后南四湖下级湖的流场变化较为复杂。为研究调水工程运行对下级湖及各个分区水体交换特征的影响,【方法】在收集南四湖下级湖地形、降雨、蒸发、风场等资料的基础上,构建了下级湖二维水动力和对流扩散模型,并进行了模型率定与验证,选取50 m^(3)/s、2020—2021年度调水期实际流量、设计流量125 m^(3)/s共3种流量工况进行了模拟分析。【结果】模拟结果显示:调水148 d时,3种流量工况下下级湖韩庄站至二级坝水位差分别为0.06 m、0.12 m、0.36 m,韩庄站至二级坝水位比降分别为1.0×10^(-6)、2.1×10^(-6)、6.2×10^(-6),下级湖平均流速分别提高0.15 cm/s、0.54 cm/s、0.87 cm/s,死水区和滞水区面积占比不断减小,湖区水体流动性大幅提升。实际流量工况模拟入下级湖共6.6亿m^(3),出下级湖6.3亿m^(3),其中下级湖旧水体占67%,外调水占33%。【结论】同一流量情况下,下级湖从南至北、从东至西水体更新时间逐渐变长,3种流量工况下下级湖水体更新时间分别为77 d、78 d、53 d。研究结果有助于定量分析调水情况下下级湖水体流动和交换过程,对南水北调东线工程南四湖段调度运行具有一定参考作用。