Epiphyton Geochemistry in the Ivankovo Reservoir

Epiphyton chemistry was studied in the Ivankovo Reservoir; a large number of micro- and macroelements (Ag, Al, As, Ba, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, S, Sc, Sr, Ti, V, Y, Yb, Zn, W) were determined with the use of up-to-date analytical methods. Comparative characteristics of the geochemistry of macrophyte epiphyton of different ecological groups is given for the Ivankovo Reservoir. The potential of epiphyton as a biogeochemical indicator of anthropogenic impact on the water body is examined.     

Origin of hydrocarbons in bottom sediments of the Ivankovo Reservoir

The composition of hydrocarbons (aliphatic and polycyclic aromatic) is studied in the surface layer of bottom sediments of the Ivankovo Reservoir. Their concentrations are found to be high both per dry mass and in the composition of C_org. The concentration range was 0.42 to 28.15% for C_org, 141.9 to 3451.8 μg/g for aliphatic hydrocarbons (0.2–51.2% C_org), and 28.2–9161 ng/g for polycyclic aromatic hydrocarbons ((0.04–6.58) × 10^?3 % C_org). The distribution of hydrocarbons is shown to be determined not only by the lithologic type of sediments, but also by their input from petroleum and pyrogenic sources.     

Determination of soil hydrophysical characteristics in the Ivankovo Reservoir watershed

The capillary-sorption potential and the unsaturated hydraulic conductivity of soils as functions of soil water content are derived for forest, meadow, and agricultural ecosystems of the Ivankovo Reservoir watershed. The parameters of van Genuchten-Mualem equations were determined for the same soils based on data on soil particle size distribution and density. Computer code HYDRUS-1D and the obtained data were used to calculate the values of field capacity of soils in forest, meadow, and agricultural ecosystems in the drainage basin of the Ivankovo Reservoir.     

Plant Pigments in the Ivankovo Reservoir Silts as Indicators of Destruction Processes

The trophic state of the Ivankovo Reservoir is evaluated based on the characteristics of phytoplankton development and silt accumulation. Data on the space and time distribution of plant pigments in silt deposits are examined. Correlation between plant pigments and the main characteristics of silts are established. The ratio of chlorophyll content of the normal annual layer of sediment accumulation to the annual primary production of phytoplankton is calculated. The bedding of gray clayey silts onto gray sandy silts is shown to correlate with an increase in pigment concentrations in the top sediment horizons.     

Resources-related and water-environmental problems of the integrated use of the Novosibirsk Reservoir

The use of water resources of the Novosibirsk Reservoir by the existing water management complex is analyzed at different stages of reservoir operation. The natural and anthropogenic factors that determine the development of reservoir water resources for water supply, a priority objective now, are discussed. The problems of water quality formation in the reservoir are considered for different hydrological seasons and periods of water abundance in the major river. The major contradictions between the participants of water management system are specified. Perspective approaches for optimizing the use of water resources of the reservoir are proposed.     

Long-Term Dynamics of Nitrogen and Phosphorus Concentrations in Subsoil Water in Ivankovo Reservoir Drainage Basin

Water Resources - The article presents the results of summer dry-season areal surveys of subsoil water chemistry in the drainage basin of the Ivankovo Reservoir in the Volga segment from Tver City...     

Assessment of the oxygen consumption rate in the water column for the Mozhaisk and Ivankovo reservoirs

Long-term studies of oxygen consumption rate in the water column of the Mozhaisk and Ivankovo reservoirs enabled the calculation of statistical dependencies of oxygen consumption rate on oxygen deficit, taking into account the trophic level and hydrological structure of the water column. On the basis of the values of oxygen deficit, the vertical distribution of water density, and water transparency, the oxygen consumption rate in the water column can be estimated.     

Adapting a model of heat and mass exchange between a water body and the atmosphere taking into account the effect of shallows: Case study of the Ivankovo Reservoir

The paper is based on a box model of heat and mass exchange with the incorporation of a block for calculating latent heat flux, supplemented by parameterization of heat and mass exchange between shallow water area and the atmosphere. The results of calculation of evaporation from the water area of the Ivankovo Reservoir, with allowance made for more intense evaporation from shallows, are given. The latent heat fluxes from shallow and deep-water zones of the water body are shown to differ, depending on weather conditions and water level; the increase in the evaporated-water volume due to taking into account the shallow-water effect is evaluated.     

Simulation of Phytoplankton Community Transformations in the Ivankovo and Rybinsk Reservoirs: Graphical Analysis

Water Resources - The paper describes a method of graphical analysis developed for freshwater ecosystems. The method was first used to analyze the structure of phytoplankton communities in the...     

Analysis of water quality and circulation of four recreational Miami beaches through the use of Lagrangian Coherent Structures

Four popular, recreational beaches in Miami, FL are Hobie Beach, Virginia Key Beach, Crandon Park Beach, and Bill Baggs Cape Florida State Park. While all of the beaches are within a few miles of each other in Biscayne Bay, they have greatly differing water qualities, as determined by the testing for fecal indicator bacteria performed by the Florida Department of Health. Using the geodesic theory of transport barriers, we identify Lagrangian Coherent Structures (LCSs) in each area. We show how these material curves, which shape circulation and mixing patterns, can be used to explain the incongruous states of the water at beaches that should be comparable. The LCSs are computed using a hydrodynamic model and verified through field experimentation at each beach.     

Indicator Ratios of Polycyclic Aromatic Hydrocarbons for Geoenvironmental Studies of Natural and Technogenic Objects

The role of polycyclic aromatic hydrocarbons (PAHs) in geoenvironmental studies is demonstrated. Indicator ratios used to identify PAH origin are considered. Their reliability is assessed for natural and technogenic objects, taking into account their stability in the environment and the specific natural conditions. The most accurate indicators are determined for identifying combustion products of domestic and medicinal wastes.     

Structural characteristics of zooplankton of the Shardarinskoe Reservoir and their use in water quality assessment

Data on the Shardarinskoe Reservoir are used to assess the indicator role of zooplankton community under unstable hydrological regime. The structural characteristics of zooplankton featured significant seasonal variations. The averaged indices characterized reservoir water quality at the level of mesotrophic and eutrophic water bodies. The possible use of cyclopidas to characterize toxic pollution of water is discussed.     

On the use of the fitting method in solving inverse problems of gravimetry and magnetometry

An analytical approach to the gravity and magnetic data inversion by the fitting method is described. The problems of the uniqueness of the solution and the convergence and stability of the iterative process are considered.     

三峡库区土地利用对河流溶解性有机质的多时空尺度影响

三峡库区拥有目前世界上规模最大的水利枢纽工程,自投入使用以来,为长江流域提供了丰富的水源及电力,促进了经济的发展,但同时也对该区域的生态环境造成了严重的冲击。澎溪河流域作为三峡库区长江流域干流的典型回水区和消落带,是众多学者研究三峡库区生态环境变化的重点区域。为探究不同时空尺度下土地利用对河流溶解性有机质（DOM）的影响,以澎溪河流域为研究对象,基于紫外-可见光谱分析和三维荧光光谱矩阵-平行因子分析,结合河段缓冲区、河岸带缓冲区及子流域3种空间尺度的二级土地利用类型,解析了旱雨季水体DOM的组成及来源特征,并采用相关分析和冗余分析方法探讨了3种空间尺度下土地利用方式对旱雨季水体DOM的多时空尺度影响。结果表明：（1）旱季水体DOM荧光组分以陆源类腐殖质所占比例更大,雨季水体DOM荧光组分以富里酸贡献为主。（2）流域内陆源输入和内源产生对水体DOM丰度均有贡献,雨季较旱季水体DOM的陆源性更强,自生源特征较弱。（3）土地利用在雨季和子流域尺度下对水体DOM的影响更显著,其中,雨季子流域尺度下,土地利用指数对水体DOM参数的解释率为90.35%。（4）不同土地利用方式对水体DOM产生的影响...     

Impacts of recreational motorboats on fishes: A review

A considerable amount of research has been conducted on the impacts of recreational boating activities on fishes but little or no synthesis of the information has been undertaken. This review shows that motor boats impact on the biology and ecology of fishes but the effects vary according to the species and even particular size classes. Direct hits on fishes by propellers are an obvious impact but this aspect has been poorly documented. Alterations in the wave climate and water turbidity may also influence fishes and their habitats, especially submerged and emergent plant beds. Sound generated by boat motors can also influence the communication and behaviour of certain species. Pollution arising from fuel spillages, exhaust emissions and antifouling paints all have detrimental effects on fishes. Finally, the use of recreational boats as vectors of aquatic invasive organisms is very real and has created major problems to the ecology of aquatic systems.     

The use of fluorescence of humic substance to characterize the hydrological structure of water bodies: Case study of the Rybinsk Reservoir

The results of comparative studies of fluorescent characteristic of humic substance and electroconductivity in the surface water layer in the Rybinsk Reservoir are presented. The hydrological structures obtained with the use of these characteristics generally coincide. This opens the way to the use of humic substance fluorescence, which allows remote measurement, as an indicator of the hydrological structure.     

Variable spatial and temporal weighting schemes for use in multi-phase compositional problems

Variable spatial and temporal weighting of the advective contaminant mole fraction term is explored as a means of reducing numerical dispersion of contaminant plumes in a multi-phase compositional simulator. The spatial schemes considered are upstream, central and a non-linear flux limiter, while fully-implicit and Crank-Nicolson time weighting are examined. The performance of each weighting scheme, in terms of stability of the Newton iteration and computational cost, is assessed for simplified problems designed to be representative of various aspects of more complex subsurface remediation problems. Results indicate that for problems with an homogeneous permeability field, the non-linear flux limited along with fully-implicit weighting gives superior performance to any other combination of spatial and temporal weighting schemes. For heterogeneous permeability fields, the macrodispersion imparted by heterogeneity dominates numerical dispersion so that smearing of contaminant mole fraction fronts does not appear to be a serious problem.     

三峡库首区非构造型水库地震的烈度衰减

非构造型水库地震具有震级小、震源浅、烈度高的特点,研究其烈度衰减对库区地震地质灾害的预测与防治具有重要的意义。根据三峡库首区近年地震实地科考原始烈度资料,选择椭圆衰减模型并对其进行二元回归分析,得到非构造型水库地震的烈度衰减关系。并与原有构造型水库地震烈度衰减关系进行比较。结果可供库区地震危险性分析与地震小区划使用。     

Saprobiological Evaluations of the Silvola Reservoir

Saprobiological analyses of phytoplankton were made with both the 10-point-system of saprobic valency and the method of the saprobic index “S”. Means, standard deviations, standard errors, and 95% confidence intervals were calculated for the results of these evaluations. The limits of the 95% confidence interval for the points for oligo- and alpha-mesosaprobity differed by approximately 8% and those for beta-mesosaprobity by 2% from the mean. For the saprobic indices this difference was only 1%. A nested analysis of variance suggested a significant variation between different sampling stations in the points for oligosaprobity, whereas in the points for beta- and alphamesosaprobity a significant variation was found between the results from the two depths of sampling. In addition to the statistical treatments, a short review of the development of saprobity in the summer of 1971 based on zooplankton data was also made.