The contribution of primary production to the overall organic matter pool in Volga reservoirs

The results of studies of the concentrations and the ratios between the forms of organic matter in Volga reservoirs are presented. The reservoirs under consideration have different morphometric characteristics. flowage, and trophic status. Total organic matter content varies from 7.1 to 11.8 g/m³ or from 39.1 to 70.8 g/m² with the proportion of labile fraction of 4.4–15.2%. The primary production of plankton, the daily value of which accounts for 14–40% of labile organic matter, has a notable effect on its concentration and input. Organic matter pool in Volga reservoirs forms under the effect of the morphometric features of reservoirs, water exchange, and the drainage area. The total characteristics of organic matter in the Upper Volga reservoirs have not experienced significant changes over the 20-year period. However, data for 2005 show that the contribution of primary production to the total concentration of organic matter and its labile fraction have decreased due to a decline in the productivity of planktonic communities recorded in recent years.     

Sedimentation in variable-backwater zones of Volga chain reservoirs

The direction and rate of sedimentation processes in variable-backwater zones—upstream river-type reaches (lower pools of hydropower systems) and large bays of reservoirs of the Volga chain (many-year aspect, mesoscale level) and in the deltas of median and small rivers in the Upper Volga region, regulated by beaver ponds (seasonal aspect, microscale level) are characterized. The changes in bed relief and the structure of sediments in the examined zones were found to have common features and pass all stage of bed and shore formation typical of lowland reservoirs-from active erosion-abrasion activity to its gradual decline and from intense to passive sedimentation.     

Comparison of reservoirs in the Moskva-Vazuza water system in terms of phytoplankton abundance and eutrophication degree

Based on the analysis of long-term data, phytoplankton biomass is shown to grow in the Vazuza-Yauza-Ruza-Mozhaisk-Ozerna series of reservoirs. The first three reservoirs (their near-dam areas) can be referred to mesotrophic water bodies and the other reservoirs, to slightly eutrophic. It has been revealed that, with an increase in the water body productivity (from the Vazuza Reservoir to the Ozerna Reservoir), the share of blue-green algae increases, while the share of diatomic algae decreases. The concentration of phosphorus in water bodies is an important factor of phytoplankton abundance.     

Diagnostic modelling of within-water processes in reservoirs

The objectives of diagnostic calculations using mathematical models of reservoirs are formulated. The structure of a box hydrological model GMV-MGU is described, and the results of calculation of daily water balance, internal heat exchange structure, and heat balance of individual areas in the Mozhaisk and Rybinsk reservoirs are given. First results of calculation of variations in mean daily phytoplankton biomass in the near-dam pool of a weakly eutrophic water body in period of spring (diatoms) and summer (blue-green) blooming are presented.     

Significance of Pigment Characteristics of Phytoplankton in Water Quality Estimating

Data on water bodies with different trophic status in the Upper Volga basin are used to analyze the relationship between the algological and pigment characteristics of blue-green alga development. The examined relationships for the phytoplankton of highly eutrophic Lake Nero are shown to feature higher correlation coefficients as compared with meso- and mesoeutrophic reservoirs.     

Fishery Water Releases to the Lower Pool of the Volgograd Hydroelectric Power Plant

Conditions of fish reproduction in the Volga–Caspian Basin depending on the hydrological regime in the Volga lower reaches, transformed by water withdrawals and regulatory impact of reservoirs are considered.     

The Efficiency of Water Resources Management in Volga Basin

The main characteristics of the socioeconomic development of Volga basin are given. Data on the use of water resources and the development of economic branches in the basin in 1980–2002 are analyzed. The dynamics of variations in the efficiency indices of water use in industry, agriculture and municipal economy in the upper, middle, and lower Volga.     

The Experience in Applying a Water Reservoir Operation Model Using Dynamic Volume Nomograms in Exercising Special-Purpose Spring Water Releases

Simulation models of river reservoir functioning in which dynamic volume nomograms are used to consider the non-horizontal nature of the reservoir water surface have not been so far applied due to the lack of accurate and fast-working computer realizations of such models. In 2015–2016, the authors of this paper developed such a program. In the periods of carrying out special-purpose spring water releases to the lower reaches of the Volga River in 2016 and in 2017, the developed model was used in a trial mode for a designing the reservoirs’ water regime. The results of water releases carried out under complicated hydrological and economic conditions proved the high performance of the model and confirmed the prospects of its application to solve the inverse problem.     

澜沧江梯级水库浮游植物群落结构特征及其关键驱动因子

筑坝改变河流生源要素迁移转化过程及浮游植物群落分布特征,影响河流生态系统结构与功能。为探究梯级筑坝河流浮游植物群落结构特征及其关键驱动因子,2016年丰水期、2018和2021年丰、枯水期在澜沧江开展了浮游植物群落及相关环境要素的调研。本文重点对比分析了丰水期自然河道段和水库浮游植物间的差异,基于广义相加模型(GAM)建立浮游植物与环境要素间的关系,研究发现:丰水期浮游植物生物量显著高于枯水期,丰、枯水期浮游植物群落结构均呈现上游以硅藻门为主,中下游以绿藻门、蓝藻门为主的变化特征。营养盐和水库的水力停留时间(HRT)是导致上、下游浮游植物生物量差异的关键环境要素;总磷、水温和HRT是影响浮游植物群落多样性指数的主要环境要素;总磷、氨氮是影响丰富度指数的关键环境要素。本研究结果有助于深化理解梯级筑坝河流生态环境效应。     

Studying the Correlation between the Vegetable Pigments Content of Bottom Deposits and the Trophic Status Indices of the Gor'kovskoe Reservoir

Data on the distribution of vegetable pigments in bottom deposits and water mass is presented to characterize the ecological zones of the reservoir. The concentrations of pigments in the channel deposits are shown to increase from the reservoir head toward the dam in accordance with the difference in phytoplankton production in the zone of backwater pinching out, transient zone, and near-dam zone. It is shown that the space heterogeneity of the pigment characteristics of deposits is controlled by the soil properties and the pigments content of the top 2.5-cm layer of bottom deposits of the reservoir correspond to the average productivity level.     

Seasonal and Year-to-Year Variations of Phytoplankton Primary Production in the Rybinsk Reservoir: The Effect of Weather and Climate Variations

Water Resources - The seasonal and long-term dynamics of phytoplankton primary production has been studied in the Rybinsk Reservoir (Upper Volga) in 2005–2014. A positive correlation has been...     

湖北浮桥河水库浮游植物初级生产力及其管理

浮桥河水库浮游植物水柱日生产量变幅为0.34-4.99 g/(m2·d),最低值出现在下游冬季,最高值出现在中游秋季,年平均值2.75 g/(m2·d)季节变化:秋季＞夏季＞春季＞冬季,与浮游植物叶绿素a含量和生物量的季节变化一致;水平分布:中游略高于上游,下游最低,与浮游植物叶绿素a含量的水平分布完全一致表层日生产量占水柱日生产量53.81%.与1980年同期相比,浮游植物初级生产力增加了1.2倍.分析表明,磷含量增加是浮游植物初级生产力提高的关键因子.应用能量收支法估算浮桥河水库鲢鳙渔产潜力为772t,516.0 kh/hm2.从渔业管理和水质管理角度讨论了合理利用浮游植物初级生产力的措施.     

Information Support Technology in Managing the Volga–Kama Cascade of Reservoirs

The paper presents the structure of information support technology and algorithms of the decision-making process in managing the Volga–Kama cascade of reservoirs, as well as the results of implementing into the operational practice of a technology for regulating reservoirs and the prospects of its use for solving water problems.     

Bacteriobenthos of the Upper Volga Reservoirs as a Characteristic of Their Environmental State

Data of long-term microbiological studies of bottom deposits in the Upper Volga reservoirs and their tributaries are given. Specific features in variations in the structural and functional characteristics of bactriobenthos in individual areas are established depending on a complex of physicochemical characteristics of water and soil and the environmental state of each water body as a whole.     

三峡水库香溪河初级生产力及其影响因素分析

2013 2014年采用黑白瓶测氧法对香溪河不同站点(上、中、下游及其支流库湾)和不同水深(0.5、1.0、2.0、5.0和10.0 m)的初级生产力进行原位测定.结果显示:(1)三峡水库蓄水后香溪河水域初级生产力具有显著的空间差异,支流和上游的总初级生产力大于中、下游,下游的初级生产力水平最低;初级生产力随着水深增加呈现逐渐减少的趋势;(2)初级生产力具有显著的季节差异,春、夏季显著高于秋、冬季;(3)光照强度、水温和天气对初级生产力有显著影响,水体叶绿素浓度与初级生产力极显著相关.结果显示,蓄水后改变的水文情势将香溪河的初级生产划分为明显不同的两个区域,水动力条件成为影响初级生产力的重要因子;依据初级生产力判断香溪河为富营养、自养代谢型水体.     

Methane and the Microbiological Processes of Its Transformations in the Water of the Upper Volga Reservoirs

Specific features of CH₄ distribution and the extent of its transformations in the water of reservoirs in the Upper Volga basin are considered. Methanogenesis was detected in water at some stations. The quantitative characteristics of CH₄ and methane oxidation are shown to correlate with the environmental conditions of the reservoir.     

Assessing the Effect of the Volga Reservoirs Chain on the Normal Annual Phosphorus Runoff into the Caspian Sea

With the help of a stationary balance model, the mean annual amounts of P retained in the chain of the Volga water reservoirs are sequentially calculated. It is found that with the current anthropogenic load, the Volga River regulation leads to a twofold decrease in the P runoff into the Caspian Sea.     

Phytoplankton and Its Pigment Characteristics as Production Indexes of the Upper Volga Reservoirs (Yaroslavl Province)

The materials presented in this paper were collected in the course of studies of phytoplankton and photosynthetic pigments in the Upper Volga reservoirs within the territory of Yaroslavl province. In 1995–2000, the phytoplankton in these water bodies was found to be represented mainly by diatom, blue-green, green, and in some cases, cryptophyte algae. It was found that in the channel parts of the reservoirs, the population of planktonic algae varied from 25 to 96180 thousand cell/l, their biomass, from 0.009 to 5.54 mg/l, and the chlorophyll content, from 0.4 to 22.4 g/l. The values of saprobity index in terms of phytoplankton were found to characterize waters of all the three reservoirs as -mesosaprobic, and the extent of blue-green algae development in the overwhelming majority of cases was classed as environmentally safe, although their abundance in the coastal zone sometimes is an indication of a substantial deterioration in water quality.     

Plant pigments as indicators of water transformation in the upper Volga Chain of reservoirs

Results of studying spatial and temporal variability in plant pigments in the Volga River water from the upper sections of the Ivankovo Reservoir downstream to the Rybinsk Reservoir Main Reach, as well as the applicability of different groups of indices of the absolute and relative concentration of pigments (chlorophylls, phaeo-pigments, and carotenoids) are presented. To differentiate water masses, these pigments have been assessed using the standard spectrophotometric method. It has been found that waters of individual river sections, singled out according to their hydrological features, and waters of different reservoirs on the whole can be reliably distinguished according to the concentration of pigments in the plant suspension.     

Phytoplankton and periphyton production and its relation to temperature in a humic lagoon

To analyse the existence of interactive competition between phytoplankton and periphyton, we studied their photosynthesis–irradiance (P–E) response during one year in a humic lagoon. Lake production was dominated by phytoplankton, which followed seasonal changes in temperature. Periphyton primary production and algae biomass increased in winter, when phytoplankton biomass and production were lower. In this study we show that even in conditions of phytoplankton dominance, the habitat coupling between phytoplankton and periphyton can still be noticed.