To investigate the spatiotemporal distribution of phytoplankton communities and their major environmental influences in the mainstream of the Yellow River (Shandong section), 29 sampling sites were surveyed in the summer and autumn of 2022 and the spring of 2023. Among the 206 phytoplankton species belonging to 8 phyla and 99 genera, Bacillariophyta, Chlorophyta, and Cyanobacteria were the main dominant groups, and Aulacoseira granulata var. angustissima (O.Müller) Simonsen, Fragilaria capucina Desmazières, and Ulnaria acus (Kützing) Aboal were the most important dominant species. The number of phytoplankton species and cell densities exhibited significant seasonal changes in the sequence of summer > autumn > spring. The phytoplankton community underwent a succession from Bacillariophyta–Chlorophyta dominance in spring and summer to Bacillariophyta–Cyanobacteria dominance in autumn. Water temperature, dissolved oxygen, and transparency were the most important factors affecting the growth of the dominant Bacillariophyta species. The spatiotemporal distribution of phytoplankton is jointly regulated by multiple environmental factors, providing a scientific basis for the evaluation and management of regional aquatic ecosystems.

To alleviate local water crises, water diversion projects are carried out in many countries around the world. However, such projects can cause a series of ecological effects with controversial consequences in water-receiving systems. Our study shows the transformations of phytoplankton communities in Datun Reservoir (DT) and Shuangwangcheng Reservoir (SWC), located on the eastern route of the South-to-North Water Diversion Project (SNWDP), China. Phytoplankton communities in these two reservoirs exhibited transient homogenization driven by the complex effects of temperature and water diversion dynamics during the first three years of the study, but ultimately diverged into distinct assemblages after ten years. Further, the newly detected Raphidiopsis raciborskii in later years showed a significant positive correlation with accumulative inflow. Combined with the increase cyanobacterial diversity observed in both reservoirs, these findings indicate that water diversion may be a pathway for cyanobacterial expansion. Moreover, low nitrogen conditions resulting from the water diversion appear to provide a competitive advantageous for nitrogen-fixing cyanobacteria (Raphidiopsis raciborskii and Pseudanabaena limnetica) over non-fixing species (Microcystis aeruginosa). Our study highlights several detrimental ecological issues affecting water-receiving systems, even in the context of improved water quality associated with the SNWDP. It also offers critical insights for managing of water-impounding systems in the future.

Dongping Lake is one of the most important regulation and storage lakes along the eastern route of the South-to-North Water Diversion Project in China, the water quality condition of which directly influences the safety of water diverting, because it serves as a Yangtze River water redistribution control point. However, the changes in algae, and in environmental factors affecting their community structures, before and after the water diversion project are rarely reported. In this study, the temporal variations of phytoplankton abundance were examined based on monthly samples collected at three stations from May 2010 to April 2022. The total abundance of algae greatly decreased after the water diversion project was implemented, with a relatively stable biodiversity and evenness before and after the water translocation. Multiple statistical methods were used together with the water quality indices (WQIs) and the nutrient status index (TSIM) to evaluate overall water condition and analyse relationships among environmental factors. The WQIs demonstrated a general “Good” water quality with a seasonal differentiation, and that water conditions during water transfer periods were better than during non-water transfer periods, which may be ascribed to the improved hydraulic conditions and purified water environment during water transfer periods. Redundancy analysis showed that water temperature, ammonia nitrogen, water transparency, and total phosphorus were the most important environmental factors, with relatively decreased contribution rates towards phytoplankton communities after the water translocation. Importantly, some dominant phytoplankton genera of Chlorophyta, Bacillariophyceae, and Cyanophyceae were similarly affected by water transparency, and nitrogen and phosphorus nutrients in summer after the water translocation. These research findings helped us gain a comprehensive understanding of the changing patterns of water quality and microalgae and their relationships before and after the water diversion project, providing a guidance for future lake management in regulating hydraulic conditions and improving water quality of Dongping Lake.

There remains no consensus on the effects of changes in the environment factors under the action of water di-versions on phytoplankton communities. Herein the changing rules applying to phytoplankton communities subject to water diversion were unveiled based on long-term (2011-2021) time-series observations on Luoma Lake, located on the eastern route of the South-to-North Water Diversion Project. We found that nitrogen decreased and then increased, while phosphorus increased after operation of the water transfer project. Algal density and diversity were not affected by water diversion, while the duration of high algal density was shorter after water diversion. Phytoplankton composition had dramatic differences before and after water transfer. The phytoplankton communities exhibited greater fragility when they first experienced a human-mediated distur-bance, and then they gradually adapted to more interferences and acquired stronger stability. We furthermore found the niche of Cyanobacteria narrowed while that of Euglenozoa widened under the pressure of water diversion. In addition to WT and DO, the main environmental factor before water diversion was NH4-N, whereas the effect of NO3-N and TN on phytoplankton communities increased after water diversion. These findings fill the knowledge gap as to the consequence of water diversion on water environments and phytoplankton communities.

To investigate the distribution characteristics of the cyanobacteria community and the driving factors in impounded lakes and reservoirs in Shandong on the east route of the South-to-North Water Diversion Project, monthly samples of phytoplankton and the aquatic environment from Nansi Lake, Dongping Lake, Datun Reservoir, Donghu Reservoir, and Shuangwangcheng Reservoir were collected from May to November during 2010 to 2019. A total of 44 planktonic cyanobacteria taxa were identified with 23 filamentous cyanobacteria taxa. Pseudanabaena limnetica, Cylindrospermopsis raciborskii, Microcystis aeruginosa, and Microcystis wesenbergii were the dominant harmful cyanobacteria species, with a high detection frequency and abundance in all lakes and reservoirs. By analyzing the distribution characteristics of the cyanobacteria community in impounded lakes and reservoirs, we found that filamentous cyanobacteria had growth advantages in the water with large hydraulic disturbances, which should be the key points of cyanobacteria prevention and control in the future. Pearson correlation analysis and generalized linear fitting curve results showed that total nitrogen, total phosphorus, water temperature, and water depth played a key role in affecting the growth of P. limnetica, C. raciborskii, M. aeruginosa, and M. wesenbergii. The nitrogen and phosphorus nutrients could promote the growth of harmful cyanobacteria. Due to the good temperature adaptability, P. limnetica could still become the dominant species in early summer and late autumn, and C. raciborskii, M. aeruginosa, and M. wesenbergii had growth advantages when the water temperature was higher than 25℃. In addition, shallow water was more conducive to the growth of C. raciborskii. It was suggested that based on strengthening of the control of nitrogen and phosphorus nutrient input in lakes and reservoirs, the key monitoring of P. limnetica in lakes should be conducted in early summer and late autumn, and the growth of C. raciborskii in shallow water areas should be paid close attention in the high temperature period to ensure the safety of water quality.

鉴于环保PPP项目类型多样,各类型项目的核心矛盾和内在规律差异较大,导致可持续影响因素及其权重的不同.为提高环保PPP项目建设的可持续性,以项目类型角度为切入,运用扎根理论中数据收集和数据分析方法对其可持续影响因素进行识别,结合问卷调查和熵权法计算权重,最终得到具有项目类型特征的可持续发展影响因素及其重要程度.利于提高环保PPP项目的管理效率,对症优化可持续建设措施.

Phytoplankton and water quality changes in highly urbanized lakes affect the surrounding water safety. However, due to the complexity and variability of natural changes and human disturbances, it is difficult for multi-year research with yearly sampling frequency to cover accurate changes of phytoplankton and water environment or provide constructive suggestions for managers. Based on monthly monitoring data spanning 2011-2020 in a highly urbanized subtropical lake (Hongze Lake, China), Mann-Kendall test, ANOVA analysis and variation partitioning analysis were used to assess the changes of phytoplankton and water environment, and detect dynamic responses of phytoplankton to environmental changes. Rising water temperature during winter and spring, the decrease in nitrate, and the increase in water flow and turbidity were the main environmental characteristics from 2011 to 2020. The average and maximum abundance of Chlorophyta, Bacillariophyta, and Cryptophyta significantly declined, while changes in Cyanobacteria were characterized by an increase of N2-fixing filamentous cyanobacteria and a decrease of non-filamentous cyanobacteria. The rising water temperature during spring may promote the early growth of N2-fixing filamentous cyanobacteria. The decrease in nitrate mainly resulted in the decrease of Chlorophyta and non-filamentous cyanobacteria, and the increase of N2-fixing filamentous cyanobacteria during summer and autumn. The increase of turbidity and water flow inhibited the growth of Chlorophyta, Bacillariophyta, Cryptophyta, and non-filamentous cyanobacteria, but created favourable conditions for the growth of N2-fixing filamentous cyanobacteria. In summer and autumn, managers should focus on the proliferation of N2-fixing filamentous cyanobacteria when precipitation increase, nitrogen nutrients decrease, and non-filamentous cyanobacteria risk under opposite conditions. These findings greatly improved our understanding of the dynamic response of phytoplankton communities to natural changes and anthropogenic disturbances in the urbanized subtropical lakes, and can be used to develop lake management strategies.

The intensity of cyanobacterial blooms that predominate in the world's lakes and reservoirs is variable, which may lead to differing effects on the freshwater ecosystem. Planktonic eukaryotes play key roles in the structure and function of freshwater ecosystems; however, little is known about the influence of cyanobacterial blooms on eukaryotic plankton communities and their function. Herein, the dynamics of eukaryotic plankton communities in Hongze Lake, which is the fourth largest freshwater lake in China, with a range of bloom levels occurred, from low to high, were studied to reveal the effect of cyanobacterial blooms' spatial heterogeneity on planktonic eukaryotes. Results showed that the diversity, richness, and evenness of eukaryotic plankton community were not affected by low level of bloom; however, they were decreased obviously by high level of bloom. Metazoa, Ochrophyta, Chloroplastida, Cryptomonadales, and Ciliophora were the main planktonic eukaryotes in this lake. Metazoa relative abundance declined 25.1% and relative abundance of eukaryotic phytoplankton (mainly Ochrophyta, Chloroplastida, and Cryptomonadales) and Ciliophora increased 17.4% and 2.0%, respectively, during the period with low level of bloom; conversely, the site with the high bloom level manifested the opposite changes. The linkage density of planktonic eukaryotic network was 0.188 and 0.138 with low and high level of bloom, respectively, indicating the stability of planktonic eukaryotes was lower when a high level of bloom occurred compared to that of a low bloom level. Our findings indicate that cyanobacterial blooms should be controlled at low level to avoid their obvious negative impact on microeukaryotes in lakes or reservoirs.

在工程项目群建设中,项目之间的关联性容易使风险事件引起的负面影响在项目群系统中扩散传染,导致项目之间发生连锁失败效应,影响系统稳定.为了构建风险传染分析模型,防范和应对风险传染问题,首先依据复杂系统理论,对项目群风险传染机理进行分析,提出包括项目组件物理结构和风险因素因果逻辑结构的双重风险传染概念模型.然后,基于此概念模型,采用超邻接矩阵改进的决策实验室法构建网络分析模型,并给出因素传染度、重要度、原因度和关键传染路径的评价指标计算方法.最后,结合实际案例进行模型验证,得出各风险传染主体的传染度排序,确定各传染主体的重要度和原因度属性,以及识别出2条风险传染关键路径.研究结果表明,工程项目群中存在多类型风险传染主体、多类型传染关系并存的风险传染机制,由网络模型分析得到的评价指标适用且有效.研究结果不仅有利于项目群管理者制定针对性的风险防范措施,提高风险管理效率,还可以进一步用于风险传染动态过程的研究.

因受"垃圾围城"困扰,我国正大力发展公私合营(PPP)垃圾焚烧发电项目.为使相应的政府补贴计算更加准确,调整更加合理,项目发展更加健康,围绕政府补贴计算方法开展相关研究.首先,通过对政府、社会资本和公众等各项目决策主体和决策层级不同利益目标的识别,采用双层规划法(BLPP)建立政府补贴静态初始定价模型.然后,考虑多因素对项目运营的动态影响,利用系统动力学(SD)构建政府补贴动态运营调整模型.最后,静态初始定价与动态运营调整模型二者协同建立形成SD-BLPP政府补贴模型.在此基础上,采用H市PPP垃圾焚烧发电项目的实例数据,运用Vensim软件验证模型的有效性,并通过调整SD-BLPP模型参数,模拟运营环境变化,分析项目效益的波动情况,给出政府补贴调整建议.结果表明,SD-BLPP模型计算出的补贴单价合理,能够优化项目效益结构,可以实现运营条件变化时的项目效益预测和政府补贴动态调整,具有较好的有效性和适用性,为PPP垃圾焚烧发电项目政府补贴提供计算方法和调整建议提供了依据.

How phytoplankton respond to changes in water resource allocations, and whether water diversion cause phytoplankton homogenization remain no incontestable conclusion. Herein the changing rules of phytoplankton communities faced to water diversion were unveiled based on long-term (2011–2019) time-series observation and analysis of algae data of three regulating lakes on the eastern route of the South-to-North Water Diversion Project in China. We found that phytoplankton composition had dramatic differences before and after water transfer; however, after long-term planned water diversion the algal structure — especially for abundant species — gradually became similar to that found in 2014, revealing the community structure was changed by water mixing, and reverted slowly to the initial state after water diversion. Phytoplankton communities exhibited greater fragility when they firstly experienced human-mediated disturbance, while gradually adapted to more interferences and obtained stronger stability. More importantly, we found that the community composition had no homogenization across three lakes after water diversion and resistance and recovery are underlying mechanisms to maintain the community heterogeneity and stability. Moreover, the altered phytoplankton communities in round lakes re-established stable states, while strip-shaped Nansi Lake not, reflecting the strip-shaped lake had slower response and less resilience to the disturbance than the round lakes.

Phytoplankton, as an important primary producer in rivers, greatly affects an aquatic ecosystem's function and biodiversity. However, the effect of human activities on phytoplankton community composition remains largely unstudied in rivers. Herein a typical temperate river, Xiaoqing River in the north of China, was the target to investigate the phytoplankton distribution and regime along stretches subject to different human disturbances. Other than in the wetland located in a tributary of the river, which had Cyanophyta as the dominant phylum, Bacillariophyta overwhelmingly predominated across the sampling sites. Notably, the main genus was Fragilaria in the source region of the river, while Cyclotella dominated along the trunk of the river, and the main species shifted from Cyclotella gamma Sovereign to Cyclotella meneghiniana Kutzing when the river entered the sea. Phytoplankton community structures in the source region were affected to some extent by DO and pH, and in the human activity areas were mainly influenced by nitrogen, phosphorus, and CODMn. Human interference led to a decrease in diatom density by increasing the concentration of nutrients and organic matter. Furthermore, algal diversity was higher and density was lower in the disturbed areas than in the catchment areas, in accordance with the intermediate disturbance hypothesis. It was also found that human activities more obviously affected the abundant than rare phytoplankton communities.

底栖蓝藻在全球淡水水域内广泛分布,在河流、湖泊、湿地、泉水水域等均有发现.相比于浮游蓝藻,底栖蓝藻因其隐蔽性、采样困难等关注度较低.针对近十几年有害底栖蓝藻不断过量繁殖的情况,本文对有害底栖蓝藻种类、主要的环境影响因子、有害次级代谢物及监测分析方法进行了总结概括.阐述了在有害底栖蓝藻生物量集聚过程中,光照、温度、营养盐、基质、水流等主要环境因子间的交互关联,并指出藻垫小生境内有害底栖蓝藻与微生物群落间作用的重要性.分析了不同属种有害底栖蓝藻的代谢物种类及影响代谢物产出的因素,总结了目前定性和定量分析有害底栖蓝藻的方法并指出其不足,对预测、定位高水平的有害底栖蓝藻提出了建议.本文为进一步研究有害底栖蓝藻异常增殖机制和有效防控方法提供了参考和借鉴.

大型建筑企业在PPP项目的投资决策中存在组合决策问题.针对这一实际问题,文章首先通过文献梳理,根据符合PPP项目特点和定性定量相结合的原则构建了基于建筑企业视角的PPP项目组合评价选择指标体系;其次运用模糊层次分析法建立PPP项目组合评价选择模型,对备选PPP项目组合方案进行评价分析;最后,用一个算例证明了指标体系和评价方法的可行性.

基于山东某新建水库中2014年4月-2017年12月的浮游藻类和水质监测结果,研究了藻类群落结构特征,采用非度量多维尺度分析了各年份不同季节藻类群落结构的相似性,利用冗余分析探究了藻类群落结构和环境因子的关系.结果表明:尖针杆藻（Synedra acus）、湖泊伪鱼腥藻（Pseudanabaena limnetica）和小球藻（Chlorella vulgaris）为此水库的主要优势藻种.水库藻类群落结构的季节演替不稳定,冬、春季多以硅藻和绿藻占优势,不同年份夏、秋季藻类结构差异较大,蓝藻和硅藻在夏、秋季存在一定的竞争优势.该水库于2013年底开始启用,由于水体环境的波动,藻类群落结构有所变化,整体上是由蓝藻-绿藻-硅藻向硅藻-绿藻-蓝藻变化.水库浮游藻类生长主要受到氮盐和高锰酸盐指数影响,但不同年份的主要环境影响因子存在一定差异.

Diatoms play an important role as ecological indicators, and some species of diatoms can easily cause water blooms, thereby decreasing the production capacity of water treatment plants and endangering drinking water safety. Mastering the diatom community dynamics is crucial for water supply. In this study, diatom composition, spatial distribution and succession were investigated in Datun Reservoir, Donghu Reservoir and Shuangwangcheng Reservoir, which are important drinking water sources in Shandong province, China. Results showed that the three reservoirs could be classified as being between mesotrophic and moderately eutrophic. The diatom community in each of the three reservoirs exhibited no obvious seasonal succession. The diatom communities in the three reservoirs were relatively simple in composition, with Synedra and Cyclotella being the most dominant groups all year round. Synedra had a negative relationship with NO2-N. Cyclotella had a positive association with NO3-N, but was negatively associated with NH4-N and CODMn in the three reservoirs. Through the analysis of diatom and environmental factors, the three reservoirs have the potential of hosting diatom blooms in summer, when the higher temperature combines with reduced water flow.

The present study was carried out in Luoma Lake, a shallow lake in temperate eastern China. Based on a two-year study, the dynamics of phytoplankton functional groups and influencing factors were analyzed. A total of 178 taxa were identified and sorted into 20 codons, according to the phytoplankton functional group classification. In order to find the environmental factors driving phytoplankton variations, fifteen groups were analyzed in detail using redundancy analysis. Groups P (Fragilaria crotonensis), X2 (Chlamydomonas globosa, C. microsphaera and Chroomonas acuta), and MP (Navicula rotaeana) were dominant during low temperature periods, whereas groups X2, S1 (Pseudanabaena limnetica), and W1 (Euglena sp.) were dominant during high temperature periods. Water temperature, total phosphorus, and ammonium were the significant driving factors explaining phytoplankton succession. Furthermore, total phosphorus and ammonium could be broadly used in risk management for potential algal blooms in Luoma Lake.

Dongping Lake is a large shallow lake, located in the east route of South-to-North Water Diversion Project in China. The variation of planktonic diatom community was recorded from May 2010 to April 2013 in Dongping Lake, aiming at exploring their indicative potential for assessment of trophic state. A total number of 52 planktonic diatom species were identified, and the abundance of planktonic diatom community ranged from 1.12x10(5) to 1.04x10(7) cells/L. The dominant diatom genera were Synedra, Cyclotella and Fragilaria, and their abundance variation could indicate the changes of trophic state and water quality. The results of redundancy analysis (RDA) showed that the variation of planktonic diatom was mainly associated with water temperature, total phosphorus, ammonia nitrogen and total nitrogen. TDI (Trophic Diatom Index), originally developed for river quality evaluation, did not adapt to assess the trophic state in Dongping Lake. Thus, the application of diatom indices in shallow lakes should be cautious.

Luoma Lake is located on the east route of the South-to-North Water Diversion Project, and it is a potential source of drinking water. From March 2011 to May 2013, the spatiotemporal distribution variation of cyanobacteria community associated with environmental factors was comprehensively investigated based on a monthly sampling. A total of 27 cyanobacteria species belonging to 14 genera were identified, and the most predominant cyanobacteria genus was Pseudanabaena, not the usual bloom-forming genera such as Microcystis and Anabaena. The cyanobacteria abundance at all the sampling sites exhibited similar spatio-temporal distribution variation, and the cyanobacteria abundance ranged over seven orders of magnitude from the undetectable level to 3.9 x 10(7) cells/L. Redundancy analysis and Pearson correlation analysis were applied to analyze the relationship between species and environment variables. The results suggested there was a positive correlation between cyanobacteria abundance and water temperature and ammonium concentration, while that between cyanobacteria abundance and dissolved oxygen concentration was negative. In addition, other environmental factors like precipitation and water turbulence could affect the cyanobacteria community distribution. Cyanobacterial blooms might not occur in Luoma Lake, with the predominant cyanobacteria genus being Pseudanabaena and water quality improved owing to the implementation of the water diversion project.