Variations in Methane Concentrations in the Water of the Don River and Taganrog Bay under the Effect of Natural Factors

Seasonal and diurnal variations in CH₄ concentration in the water of the Don River and Taganrog Bay are examined, and two maximums are recognized in the seasonal variations. The diurnal variations are shown to be affected by the meteorological conditions.     

Natural and Human-Induced Variations in Water and Sediment Runoff in the Danube River Mouth

Long-term natural and human-induced variations in water and sediment runoff in the Danube Delta head were studied on the basis of analysis of an extremely long series of observations (1840–2002). A considerable reduction of sediment runoff in the second half of the 20th century related to sediment accumulation in reservoirs was revealed. It was found that human activities had an insignificant impact on the water runoff variations and the period of 1961–2002 turned out to be abnormally water-abundant.     

Effect of Natural and Anthropogenic Factors on Soils,Soil Water,and Subsoil Water in Kola Peninsula

The concentrations of mobile compounds of S, Cu, and Ni are determined in podzol soils in the Murmansk region taken at different distances from Severonikel Copper–Nickel Plant and their variations are analyzed. The concentrations are found to have an effect on the distribution of these elements in lysimetric and subsoil waters.     

Effect of Anthropogenic Load Variations on the Hydrochemical and Hydrobiological Regime of the Ivan'kovo Reservoir

Ten-year dynamics of pollutant input from point and non-point sources in the Ivan'kovo Reservoir basin is analyzed. The shares of input components of the water balance in the anthropogenic load on the water body are specified. Data confirming the effect of significant reduction in pollutant input on the reservoir water quality, bottom sediments, and biota are presented.     

Marker Indices for Assessing the Conditions of Water Bodies under Moderate Anthropogenic Impact: Case Study of the Pra River

A system of marker-based estimates of the environmental conditions of water bodies in the Pra River basin is proposed based on the results of field studies and archive data. Correlation equation were derived for relating the selected markers with other indices.     

Natural and Anthropogenic Variations of the Concentrations of Iron,Copper, and Zinc in Water Streams of the Republic of Bashkortostan

The natural and anthropogenic sources of iron, copper, and zinc in water streams in the Republic of Bashkortostan are considered. Statistical analysis of long-term hydrochemical monitoring data was used to establish the spatial year-to-year and annual regularities in metal concentrations in water streams. The acceptability of river water quality for different types of water use was estimated. The exceedance probabilities of metal MAC values in streams were evaluated.     

Long-Term Dynamics of Phytoplankton in the Mozhaisk Reservoir and Its Production–Destruction Processes under Anthropogenic Effect

Data of observations made in 1967–1996 on the Mozhaisk Reservoir were used to examine the dynamics of primary production and destruction and their proportion. The species and size structure of the phytoplankton community was found to have changed significantly and the community biomass, to have increased in the course of long-term succession.     

Anthropogenic and Natural Components of Hydrocarbons in the Water of Lake Nero in Yaroslavl Oblast

The results of studies of spatial and seasonal variations in hydrocarbon concentrations in hypertrophic Lake Nero are used to discuss the problem of division of hydrocarbons into anthropogenic and natural components. It is shown that the use of bitumoids as a component of oil pollution instead of total organic matter can introduce errors in the results. Seasonal variations in the activity of hydrobionts in an undisturbed area are shown to have a notable effect on the assessment of the proportion of anthropogenic hydrocarbons in their total concentration, that is, on the assessment of the extent of pollution of water bodies. The natural component is found to dominate over the anthropogenic component only in the periods of algae blooming. In spring and autumn, the total concentration of hydrocarbons was found to exceed the MAC and to be due mostly to natural hydrobiological factors.     

Long-Term Water Level Variations in the Eastern Sea of Azov and in the Mouth Reach of the Don River

Studies of long-term water level variations at marine hydrometeorological stations in the eastern Sea of Azov established a rise in the sea level which accelerated in the past 40 years. Allowance for the tectonic component permitted assessing the average rate of eustatic rise in the level. Oppositely directed long-term level variations were established in the mouth area of the Don River. Water level was found to rise at the downstream gages because of the backwater effect caused by the Sea of Azov level rise and delta deposits subsidence and to drop at the upstream gages mainly because of bed erosion owing to a reduction in sediment runoff after the construction of the Tsimlyanskoe Reservoir.     

Nucleation and Evolution of Sliding in Continental Fault Zones under the Action of Natural and Man-Made Factors: A State-of-the-Art Review

Izvestiya, Physics of the Solid Earth - Abstract—A review is presented of the state-of-the-art publications concerning the nucleation and evolution of fault slip in the Earth’s crust....     

Probabilistic Regularities in Setup Variations in the Level of a Large Inland Water Body: Case Study of the Caspian Sea

The results of probabilistic analysis of data on setup level variations collected during long-term observations at all gages along the Caspian Sea coast are discussed. A procedure for evaluating low-probability sea level extremes is proposed. Estimates are given for the probabilities of outstanding setups in the Caspian Sea and the Sea of Azov.     

Mapping of the Natural and Anthropogenic Landscapes of River Deltas in Different Regions of the World Using Satellite Imagery

Water Resources - The article suggests a method of mapping the natural and anthropogenic landscapes of river deltas based on satellite imagery in the publicly accessible information system Google...     

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...     

Regularities in the Space and Time Flow Variations in the Near-Mouth Reach and Delta of the Lena R.

Lena flow showed considerable, mostly climate-induced, changes in the recent 30–40 years. The character of these changes at the river watershed–sea border somewhat differs from that in the basin outlet station because of flow transformations in the near-mouth reach and, especially, in the delta. The new stationary and occasional expedition observations were used to improve the estimates of the major characteristics of the discharges of water, suspended sediment, and heat in the Lena outlet section and to identify the features and causes of their long-term and seasonal variations. Another important result is the estimation of flow characteristic in the reach downstream of the basin outlet station, at delta head, and on its coastline. New data are given on the present-day distribution of water and suspended sediment discharges between the major delta branches, their long-term variations, and the character of inundation of the near-head delta area during spring floods.     

Land Application of Sulfate Salts for Enhanced Natural Attenuation of Benzene in Groundwater: A Case Study

Sulfate reducing conditions are widely observed in groundwater plumes associated with petroleum hydrocarbon releases. This leads to sulfate depletion in groundwater which can limit biodegradation of hydrocarbons (usually benzene, toluene, ethylbenzene, xylenes [BTEX] compounds) and can therefore result in extended timeframes to achieve groundwater cleanup objectives by monitored natural attenuation. Under these conditions, sulfate addition to the subsurface can potentially enhance BTEX biodegradation and facilitate enhanced natural attenuation. However, a delivery approach that enables effective contact with the hydrocarbons and is able to sustain elevated and uniform sulfate concentrations in groundwater remains a key challenge. In this case study, sulfate addition to a groundwater plume containing predominantly benzene by land application of agricultural gypsum and Epsom salt is described. Over 4 years of groundwater monitoring data from key wells subjected to pilot‐scale and site‐wide land application events are presented. These are compared to data from pilot testing employing liquid Epsom salt injections as an alternate sulfate delivery approach. Sulfate land application, sulfate retention within the vadose zone, and periodic infiltration following ongoing precipitation events resulted in elevated sulfate concentrations (>150 mg/L) in groundwater that were sustained over 12 months between application events and stimulated benzene biodegradation as indicated by declines in dissolved benzene concentration, and compound‐specific isotope analysis data for carbon in benzene. Long‐term groundwater benzene concentration reductions were achieved in spite of periodic rebounds resulting from water table fluctuations across the smear zone. Land application of gypsum is a potentially cost‐effective sulfate delivery approach at sites with open, unpaved surfaces, relatively permeable geology, and shallow hydrocarbon impacts. However, more research is needed to understand the fate and persistence of sulfate and to improve the likelihood of success and effectiveness of this delivery approach.     

Tidally‐averaged flows in the interior Sacramento–San Joaquin River Delta: Trends and change attribution

The hydrology of the San Francisco Bay‐Delta estuary (the Delta) has been significantly modified over the past 150 years to serve a variety of human needs for water supply and food production, albeit with adverse ecological impacts. These adverse impacts, in concert with evolving societal values, have motivated change in the estuary's water management to promote ecosystem restoration goals while continuing to support human uses. Understanding historical flow patterns, as well as the environmental functions provided by these flow patterns, is critical to restoration planning. Building upon previous work on outflow trends from the Delta to San Francisco Bay, this paper evaluates historical trends in key interior Delta flows spanning nine decades (1922–2016) and presents an attribution of these trends to various anthropogenic drivers. We reconstructed historical time series records at four key locations in the interior of the Delta; these time series represent tidally‐averaged flows that are intensively managed and are of great importance to the beneficial uses of water in the region. We derived several scenario‐based flow time series at these same four locations to assist in attributing change to a variety of drivers, including reservoir and export pumping operations, in‐Delta barrier and gate operations, and upstream water diversions. Flow changes were measured relative to 1920‐level land use and water management conditions. We find the four interior Delta locations to have distinct seasonal flow trends and, in general, unique responses to various drivers of change. Our work highlights the complex nature of historical flow changes in a highly‐managed estuarine ecosystem, and the types of modifications that would be necessary to reverse these changes.     

Water Chemistry Formation in Lakes of Specially Protected Natural Areas in the Altay Mountains: Case Study of the Mul’ta River

Water Resources - Mass-spectrometry with inductively coupled plasma was applied to determine the dissolved forms of 26 elements in the water of lakes of the Mul’tinskii Basin. Specific...