Influence of long-standing changes of hydrological and hydrochemical regime of Novosibirsk reservoir on ecological conditions of water use

The paper investigates the potential use of Novosibirsk reservoir for organizing water supply, including drinking water, of the large city and adjacent territory. The characteristics are given of the long-standing formation of hydrological and hydrochemical regime of the reservoir and its influence on the ecological conditions of water use.     

基于多水文改变指标评价东江流域河流流态变化及其对生物多样性的影响

新丰江、枫树坝和白盆珠3座大型水库的建立对东江流域河道流量和河流流态过程有了较大改变,威胁河道下游生态系统的健康。基于广义指标生态剩余和生态赤字评价了东江流域受水库影响后流域生态需水需求目标总的盈余和缺失变化过程,基于IHA32指标计算的Do和DHRAM评价了水库对下游河段河流水文过程总的改变程度以及威胁河道生态系统健康的风险性大小,并进一步分析了对河道生物多样性的影响。研究结果如下:(1)水库对流量历时曲线(FDC)有显著影响,曲线上部下降,尾部上升,尤其体现在秋季和冬季。降水对年与夏季生态剩余影响较大,水库对各季节生态剩余和生态赤字均有较大影响:秋季和冬季生态赤字几乎为0,生态剩余显著增加。生态剩余和生态赤字与大部分IHA中32个指标具有很强的相关性,可作为衡量东江流域年和季节径流变化的生态指标。(2)龙川、河源、岭下和博罗4站点总体改变程度分别为58.48%、54.04%、54.32%和52.47%。河流流态变化导致总季节生态剩余增加并维持在较高水平,进一步引起河流生物多样性下降,并维持在较低水平。龙川和河源两站河流流态的变化对河流生态系统造成了高风险性影响,岭下和博罗两站则为中等风险。     

Response of macroinvertebrates and water quality to long-term decrease in organic pollution in some Estonian streams during 1990–1998

A survey was started in 1990 of the benthic macroinvertebrate community and water quality in some Estonian streams affected by organic pollution, especially the spreading of slurry on fields. The study was expanded during 1991–1998 to involve 47 sampling sites. Long-term dependence was tested using the SAS/GLM contrast statement. All biological indices used (BMWP-ASPT, number of ASPT scoring families (N_ASPT), Danish Fauna Index, Belgian Biotic Index, EPT-index) were significantly related to the degree of organic pollution. Compared with the reference sites, the test sites revealed significantly lower water quality: higher BOD₇, total P and NH₄; lower pH and all hydrobiological indices. Season and stream size at the sampling site (expressed in km from the stream source) had significant effects on both hydrochemical and hydrobiological variables. On the contrary, discharge and precipitation had no significant influence on the studied water quality indicators, with the exception of pH in a few cases. At the same time, all but three variables for the reference and the test sites were different at the beginning of the sampling period; this difference remained only for a few sensitive indices such as ASPT and Danish Fauna Index at the end of the period, indicating general improvement in the environment.     

Hydrobiological Outline of the Mongolian Lakes

The waters of Mongolia can be classified according to their catchment areas into three hydro-geographic regions: basin of the Arctic Ocean, basin of the Pacific Ocean, Central Asian basin without outlet. After a short historical survey of the exploration of the lakes of the Mongolian People's Republic, the formation and the classification of the lake system is briefly dealt with. Recent hydrobiological findings are presented in addition to hydrological data. As far as possible, statements are made on the size and the depth of the waters, the growth of macrophytes and the trophic level of the lakes. A distinction is made between ultraoligotrophic, oligotrophic, mesotrophic, eutrophic and dystrophic waters. They are characterized by data on the biomass of the plankton and the ichthyofauna. In the zooplankton of the Central Asian basin, 17 copepod, 29 cladoceran and 58 rotatorian species, and in the waters belonging to the drainage basin of the Pacific Ocean 16 copepod, 40 cladoceran and 37 rotatorian species have already been identified. The results represent the basis for an intensification of fishery in the Mongolian People's Republic.     

Vegetation characteristics and eco-hydrological processes in a pristine mire in the Ob River valley (Western Siberia)

Relations between vegetation characteristics and eco-hydrological processes were assessed in a pristine mire in the valley of the Ob River (Western Siberia). Along a transect from the terrace scarp to the river, field data were collected on vegetation composition, peat stratigraphy, peat chemistry, hydrology and hydrochemistry. Based on floristic composition, eight vegetation communities were distinguished. Hydraulic head measurements were used to obtain an indication of groundwater flow directions. The water balance of the mire was calculated with a two-dimensional steady-state numerical groundwater model. Water types were defined based on cluster analysis of hydrochemical data. The results revealed that the dominant hydrological factor in the Ob mire is the discharge of groundwater, which supplies about threefold more water than net precipitation. Although the discharge flux decreases with increasing distance from the terrace scarp, high water levels and a “groundwater-like” mire water composition were observed in the major part of the study site. Precipitation and river water play only a minor role. Despite dilution of discharging groundwater with rainwater, spatial differences in pH and solute concentrations of the surficial mire water are small and not reflected in the vegetation composition. Although small amounts of silt and clay were found in the peat in the proximity of the river, indicating the occurrence of river floods in former times, no river-flood zone could be recognized based on hydrochemical characteristics or vegetation composition. A comparison of the Ob mire with well-studied and near-natural mires in the Biebrza River valley (Poland) revealed substantial differences in both vegetation characteristics and the intensity and spatial pattern of eco-hydrological processes. Differences in the origin and ratios of water fluxes as well as a dissimilar land use history would seem to be key factors explaining the differences observed.     

Analysis of the effects of climate-dependent factors on the formation of zooplankton communities that inhabit arctic lakes in the Anabar River Basin

The major structural characteristics of zooplankton communities that inhabit 35 Arctic lakes in the catchment basin of the Anabar River (Yakutia) have been analyzed. The ecological state of the lakes has been evaluated. The structure-forming abiotic factors that have the greatest influence on the formation of zooplankton communities have been revealed using the indirect ordination method.     

Seasonal trends in transformation of organic matter forms and enzyme activities in aquatic environment in winter in the Russian Arctic Seas by the example of Yenisey Estuary

Time variations in the main hydrochemical indices of water, organic matter forms, and hydrolytic enzyme activities in aquatic environment have been studied in winter in the southeastern Kara Sea (Yenisey Estuary with depths from 29 to 31 m). The abundance of some components of microproducer (pico-, nano-, and microphytoplankton) and bacterial plankton communities has been analyzed. High functional activity of microcommunities has been demonstrated in winter hydrobiological period. The hydrological, hydrochemical, biochemical, and biological indices of aquatic environment considerably varied in time while their stratification remained stable. The total resources of biologically accessible dissolved organic matter was evaluated by splitting the biological oxygen demand curves obtained under standard conditions (at 22°C).     

长江流域生态系统水文调节服务空间特征及影响因素:基于子流域尺度分析

水文调节服务是流域生态系统所提供的重要服务之一,认识流域生态系统水文调节服务空间变异规律及其驱动力,对于流域生态系统保护与恢复、合理开发利用水资源具有重要意义。以洪涝灾害频发的长江流域为对象,运用变异系数法和多元统计方法,在子流域尺度上研究了长江流域生态系统水文调节服务空间特征及影响因素。结果表明,长江流域子流域生态系统水文调节服务呈现出明显的空间异质性,水利工程密集、自然植被覆盖率高达71%的金沙江和汉江水系各子流域水文调节服务最强,降雨与径流变异系数差为0.477;农田和人口密集的嘉陵江水系各子流域水文调节服务最弱,降雨与径流变异系数差为-0.474,其他子流域水文调节服务作用不明显。影响水文调节服务的主要因素是:水库库容、自然植被面积比例、农田面积比例、单位面积人口数,其中:水库库容和自然植被面积比例对水文调节服务具有正向促进作用,农田面积比例和单位面积人口对水文调节服务的作用正好相反。水库库容对子流域生态系统水文调节服务空间异质性的贡献最大(58.85%)。上述结果有助于科学认识长江流域生态系统水文调节服务空间分异规律,可为制定不同子流域生态保护与恢复措施、提升子流域生态系统水文调节服务提供科学依据。     

Equitable and reasonable freshwater allocation based on a multi-criteria decision making approach with hydrologically constrained bankruptcy rules

Effective water allocation among multiple jurisdictions is a key instrument to improve water use efficiency within the basin scale. To achieve equitable and reasonable water allocation, natural, socio-economic, and ecological conditions within a specific basin need to be systematically considered. Based on the main principles of equitable and reasonable water allocation that were defined by UN Watercourses Convention, an integrated multi-criteria decision making (MCDM) with bankruptcy rules (IMCDM-BR) under multiple hydrological constraints were proposed to allocate trans-jurisdiction water resources in Guanting reservoir basin (GRB), a shared basin between Zhangjiakou and Beijing in China. Projection pursuit (PP), as one of an effective MCDM approach, was employed to synthesize values of the related principles, which were ranked as weights for the corresponding water claims by relevant agents. Then, the weighted bankruptcy rules (BR) with multiple hydrological constraints were applied to allocate water among the related agents of the studying basin. The results of ordinary bankruptcy rules, bankruptcy rules with regular and hydrological constraints, and the proposed methods were compared and discussed. Among them, the proposed IMCDM-BR was recommended as an effective tool to support practical water allocation. Moreover, factors of equitable and reasonable water allocation were comprehensively considered. The results can thus be used for facilitating negotiation in trans-jurisdiction water allocation among agents within basins.     

A large reservoir as a source of zooplankton for the river: structure of the populations and influence of fish predation

Within an extensive programme on the Seine river, including the large reservoirs in the upstream basin, zooplankton populations were investigated at the reservoir-river interface to find out their fate when released into the river. Zooplankton structure, abundance and biomass were analysed in the river upstream and downstream from the reservoir, in the release canal and in the reservoir. Whereas the river zooplankton are dominated by rotifers, microcrustaceans represent a large part of the population in the reservoir, because of the longer residence time (6 months). We have shown that the reservoir is a source of zooplankton; we calculated a biomass export of 30-60 tons C year^-1, which is, however, rapidly lost in the river. One of the main loss factors was found to be selective fish predation on larger zooplankton species developed in the reservoir.      

水文变异条件下鄱阳湖流域的生态流量

受气候变化和人类活动综合影响,鄱阳湖流域水文状况发生变异。河流生态系统适应了变异前的水文状况,变异后势必会影响当地生态系统。基于此,采用8种变异检测方法对水文变异进行综合诊断,阐明水文变异原因。在此基础上,采用15种概率分布函数分别拟合5站各月变异前日流量序列,最终确定5站点各月最优分布函数及所对应的概率密度最大处的流量,即得河道内生态流量。研究表明:(1)抚河于1962年发生弱变异,赣江、修河于1968年发生中变异,信江、饶河于1991年发生弱变异;(2)变异后,赣江、信江、饶河、修河生态需水满足率平均上升11%,抚河生态需水满足率下降32%;(3)水文变异增加提高生态需水满足率,水利工程建设降低年均生态需水满足率、提高干季生态需水满足率。高森林覆盖率提高干季生态需水满足率,对年均生态需水满足率影响不明显。研究结果为鄱阳湖流域水资源管理及区域水资源规划与配置提供重要科学依据。     

Distribution and Interannual Changes of the Zooplankton of the Durgun Water Basin and Adjoining Water Objects (the Western Mongolia)

The article describes quantitative and structural characteristics of zooplankton of polytypic sites of a water system including a lake, canal, and a water reservoir. It is shown that in the littoral zone of lakes and water reservoirs, the number of species and communities is higher, and biomass, lower. However, in the littoral zone of shallow lake zooplankton in number, took priority due to Rotifera, in the deep part of the water body – Rotifera and Cladocera; in the center of the lake zooplankton dominated by biomass due to Cladocera and Copepoda, in the water reservoir—due to the Copepoda. The dam area of the water reservoir had the highest species richness of zooplankton among all studied sites. The greatest number and biomass of zooplankton within a waterbody are noted in upper part, where a sedimentation zone had formed, and as a whole for the system of the investigated waterbodies, the maximum quantity indices are typical of lake communities. It is revealed that the starkest interannual changes in zooplankton were observed in the shallow lake: the number of species decreased—in the littoral zone at the expense of Rotifera, and in the center, the biomass increased at the expense of Cladocera; in deep-water area of the dam area of the reservoir, conversely, the number of species, as well as the number and biomass of the community, increased due to Copepoda.     

极端水文干旱下鄱阳湖浮游动物群落结构特征及其影响因素

2022年鄱阳湖流域发生了特大干旱事件,对鄱阳湖生态环境产生了严重影响。为揭示极端水文干旱年的鄱阳湖浮游动物群落结构特征及其主要影响因素,于2022年1月(冬季)、4月(春季)、7月(夏季)和10月(秋季)对鄱阳湖浮游动物进行了综合调查。本次调查共鉴定出浮游动物70种(轮虫40种、桡足类17种和枝角类13种),丰度和生物量范围分别为0—152.67个/L和0—1.52 mg/L。浮游动物群落结构具有较大的时空差异：在季节上,物种数夏季最多,丰度和生物量呈现夏季最高、秋季最低的特征,干旱季节的Shannon-Wiener多样性指数和优势种组成明显不同于非干旱季节;在空间上,南部湖区的物种数、丰度、生物量高于北部湖区,多样性指数在中部湖区最高、北部湖区最低。极端水文干旱年的物种数、丰度和生物量均明显低于往年同期,但空间上的差异较小。相关性分析和冗余分析结果表明,浮游动物群落结构在干旱季节和非干旱季节的主要影响因素存在明显差异,其中干旱季节浮游动物群落结构主要受水温、水位、硝态氮、氨氮等的共同影响,非干旱季节受化学需氧量和水位的影响较大。总体上,极端水文干旱使得鄱阳湖浮游动物群落结构稳定性较...     

Influence of the fish pond aquaculture effluent discharge on abiotic environmental factors of selected rivers in Northwest Poland

Pollution of rivers caused by human activity is a widely discussed problem, however there is not much attention paid to the changes of water quality that result from the inflow of effluent discharged from fish breeding ponds. The paper presents results of studies on changes of the abiotic parameters (hydrochemical and hydrological) of water observed in the yearly cycle between 2004 and 2008 in selected rivers of Northwest Poland. It was proved that the fastest reaction on the inflow of the effluent discharged from the fish ponds was reflected in changes of biogenic and organic compounds in the river water. The largest, i.e. threefold (rivers Krapiel and Tywa) or even fourfold (rivers Rurzyca and Stepnica) increase in nutrients and organic matter was recorded during the pond effluent discharge into the rivers. At that time values of the organic matter ranged from 8.9 to 18.3 mgO₂/dm³ (BOD₅), the nitrogen compounds from 16.868 to 26.930 mgN/dm³, while the phosphorus from 1.928 to 6.353 mgP/dm³. Interestingly, an additional dry mass of seston was recorded no earlier than the activity of the harmful element had been stopped and the river had resumed to the “initial” state (i.e. before the effluent discharge); that period varied from one to two months, depending on the river characteristics. The highest values of the dry seston mass (580.9 mg/dm³) was recorded in river Krapiel in November 2006. It seems that in spite of remarkable influence on values of individual physical and chemical indices of the river water quality, the effluent discharge from the fish ponds is not a factor hampering the self-purification processes of the rivers.     

Water masses and zooplankton in a tributary of the Rybinsk Reservoir in its backwater zone

In 2008, transition (gradient) and stable zones in backwaters of the tributary of the Rybinsk Reservoir were distinguished according to water conductivity. The highest values of BOD₅ (biochemical oxygen demand) and the maximum zooplankton abundance within the backwater zone as well as in comparison with the neighboring systems (the river and the reservoir) were recorded in the transition zone where the marginal effect appeared.     

Zooplankton biomass and community structure in a Danube River floodplain system: effects of hydrology

1. Zooplankton density and biomass was examined in a Danube River floodplain section with highly variable hydrological dynamics. Temporal patterns were analysed to assess the effects of hydrological conditions on zooplankton community structure and the differential response of the two major zooplankton taxa, rotifers and crustaceans.
2. Calculated floodplain water age was used as an integrated parameter describing hydrological conditions and connectivity.
3. Total zooplankton biomass, crustacean biomass and crustacean species number were significantly positively related to water age. Rotifer biomass followed a hump-shaped relationship with water age, and rotifer species number decreased with increasing water age.
4. Rotifers dominated the community in periods of low to medium water ages. In periods of higher water ages the community was dominated by crustaceans.
5. We propose that the hydrological regime of floodplains is crucial for zooplankton biomass patterns and succession, through the alternation of washing-out effects, taxon-specific potential of reproduction and biological interactions. Flood events and high water levels reset the community to an early successional phase.     

Use of Macrophytes in Assessing the Ecological Status of Small River (by the Example of the Okhta River,St. Petersburg)

Hydrochemical and hydrobiological characteristics have been studied at 13 sites in the Okhta River within the precincts of St. Petersburg in 2010. The Water Pollution Index (WPI), calculated according to hydrochemical parameters, characterizes the river water quality as “very polluted” to “extremely polluted.” According to the Pantle–Buck–Sláde?ek Saprobity Index, obtained on the basis of macrozoobenthos characteristics, polysaprobic and α-mesosaprobic zones can be distinguished in the watercourse. The species richness of river macrophytes is low (18 species). The Macrophyte Water Quality Index makes it possible to assess water quality in the range from “polluted” to “very polluted” water. Macrophyte trophic indexes MTR, IBMR and TIM indicate a high trophy level in the watercourse sites. Based on the analysis of hydrochemical materials and the data on macrozoobenthos and macrophytes, the general tendency is similar: deterioration of water quality downstream. Macrophyte characteristics reflect changes in hydrochemical parameters downstream the river course. А strong correlation (r =–0.76) is found between the Macrophyte Water Quality Index and WPI. The possibility of using the data on macrophytes in small rivers for assessing water quality is demonstrated.     

Influence of groundwater exploitation on the ecological status of streams in a Mediterranean system (Selva Basin,NE Spain)

The ecological status of streams depends on an equilibrium between hydrological processes and biological dynamics. Water discharge is the main requisite for a wealthy riparian habitat. Nevertheless, human practices severely affect water availability through stream water derivation and groundwater withdrawal. In this sense, impacts upon aquifer water storage and its effects on base flow generation have a significant effect on stream biology. Consequently, biological indicators will point out poor conditions resulting from such human impacts. In this paper, the effects of groundwater exploitation on stream discharge and surface water quality are evaluated and compared to biological indicators in a Mediterranean catchment.The stream–aquifer relationship is investigated by considering the hydrological context of each river reach, including human pressures, and the hydraulic head in the contiguous alluvial aquifer, where it exists. These data allow us to differentiate distinct types of reaches that are defined according to a “Stream–Aquifer relationship and chemical Pressure” (SAP) classification, which is used later on to standardize the different hydrochemical and biological features of the sampling points.Stream water and groundwater hydrochemistry are compared to depict the hydraulic behavior of the sampled watercourses during wet and dry periods. Specific elements are used as tracers of groundwater inputs, wastewater influence, or even stagnant conditions during the dry season. This dataset defines a framework to interpret the biological status of each reach based on the Iberian biological monitoring working party indicator (IBMWP). Affinities between hydrological and hydrochemical conditions with biological indicator values allow the causal effects of groundwater exploitation on stream ecology to be defined.The use of multivariate principal component analysis shows that the dataset variance is distributed according to the SAP classification, and that variable grouping is in agreement with the observed hydrological processes and their effects on biological indicator values.This work provides evidence of the importance of groundwater dynamics on biological indicators in a human-modified environment. When using the SAP classification, biological indicators acquire a broader meaning as they reveal the status of biological processes and the causal references. Such information is relevant for water management assessment within the context of the European Water Framework Directive, as it emphasizes the control of groundwater exploitation as a key parameter in the preservation of stream ecological status and the achievement of the objectives of the directive.     

Zooplankton abundance in the River Danube, Austria: the significance of inshore retention

1. Zooplankton density was examined in a free-flowing section of the River Danube, Austria. Spatial and temporal patterns were used to identify mechanisms regulating zooplankton dynamics. 2. Zooplankton abundance differed significantly between sampling sites. These differences were the result of variations in water residence time within the habitats. Inshore habitats with low flushing rates act as storage zones for zooplankton. 3. The hydrological conditions govern the number and size of storage zones. In the study area, the highest availability of storage zones was observed at medium water level. 4. Total zooplankton numbers, total rotifer numbers and the densities of the most abundant rotifer taxa were significantly positively related to the availability of adjacent storage zones. 5. The present authors propose that inshore retention capacity, and the hydrological processes and mechanisms controlling the extent of inshore retention may be of major significance in regulated rivers with high water velocities, preventing substantial zooplankton growth in the main channel.