Mathematical modeling of oil hydrocarbon transformations in different parts of the White Sea

The available observational data on variations of oil hydrocarbon concentrations in White Sea tributaries and in individual parts of the sea are analyzed, and the contributions of different external sources to marine environment pollution are evaluated. The results of calculations are used to determine the possible total input of hydrocarbons from additional potential sources—internal natural (production by microorganisms) and external anthropogenic (navigation and sea shipping), which are most active in the summer and autumn. The hydroecological CNPSi-model is used to reproduce the processes of pollution of nine areas in the White Sea by oil hydrocarbons and their subsequent biodegradation in the marine environment. The annual dynamics of hydrocarbon concentrations was calculated using the long-term annual observations of monthly variations of the temperature, light intensity, and transparency of water, data on the morphometry of sea areas (the squares, mean depths, and water volumes) and water exchange between the chosen areas, calculated by a hydrodynamic model. For large bays (Dvina, Kandalaksha), the calculated concentrations of oil hydrocarbons are shown to be in agreement with the available estimates (the mean and maximal concentrations). The annual variations of oil hydrocarbon concentrations; the biomasses, oxidation activity and bioproduction characteristics of oil hydrocarbon-oxidizing bacteria are characterized. The calculated internal fluxes of oil hydrocarbons (the inputs from different sources, horizontal transport, and biotransformation) were used to calculate their annual balances for individual areas and the sea as a whole, showing the balanced character of their fluxes with the total balance discrepancies for individual areas varying within 0.3–4.1%.     

Mathematical modeling of marine environment pollution processes by petroleum hydrocarbons and their degradation in Caspian Sea ecosystem

The available observational data on the pollution of tributaries and areas of the Caspian Sea by petroleum hydrocarbons and products are examined. The possible petroleum input from sources in the sea is assessed using up-to-date data of satellite observations of sea surface pollution by oil films. The hydroecological CNPSi-model is applied to studying water pollution processes by petroleum hydrocarbons in ten areas chosen in the Caspian Sea and the subsequent biodegradation of those pollutants. The model calculations of the within-year dynamics of petroleum hydrocarbon concentrations use mean annual observational data on within-year variations in water mediium characteristics (water temperature, light intensity, and transparency), as well as the morphometric parameters of sea areas (the area, mean depth, and water volumes). The characteristics of water exchange between the areas were evaluated using a hydrodynamic model. The model calculations were used to characterize the within-year variations in petroleum hydrocarbon concentrations, the biomasses of petroleum-oxidizing bacteria, the characteristics of their oxidation activity and bioproduction, and the internal fluxes of petroleum hydrocarbons (their input from various sources, horizontal and vertical transport, and biotransformation) in different sea areas. Calculation results were used to compile annual balances for the processes of input and consumption of petroleum hydrocarbons in the chosen and aggregated sea areas.     

Petroleum hydrocarbons in the waters of major tributaries of the White Sea and its water areas: A review of available information

The White Sea is a natural analogue of arctic seas. The pollution of the sea by petroleum hydrocarbons is not high now. However, the load on sea ecosystem can increase in the nearest future because of the anticipated industrial development in its watershed, including an increase in oil, coal, and diamond production. The specific features of the nature of arctic marine systems (hydrological, ice, hydrobiological, hydrochemical, and radiation regimes), and the poor knowledge of the conditions of dispersion, transformation, and utilization of petroleum hydrocarbons in such seas make their ecological studies especially important. Petroleum hydrocarbon concentrations in the waters of tributaries and water areas of the White Sea (for 1980–2006 and 1989–2006, respectively) were evaluated using literary and authors’ data. Analysis of the collected materials shows that the majority of petroleum hydrocarbons enter the sea’s water areas with river runoff. Petroleum hydrocarbon concentrations were evaluated in major tributaries of the sea, including the rivers of Northern Dvina, Onega, Mezen, Niva, Kem, and Keret, delivering petroleum hydrocarbons into the bays of Dvina, Onega, Mezen, and Kandalaksha, water area near the Solovetskie Islands, and Chupa Bay, respectively (Bay — Gulf). Model calculations should yield within-year variations in petroleum hydrocarbon concentrations in different part of the sea (under a correctly specified load) and the conditions of their biotransformation and horizontal transport through the boundaries between areas within the sea.     

Hydrocarbons in the Suspension and Sediments of the Baltic Sea

The article gives the results of studying the concentration and composition of aliphatic and polycyclic aromatic hydrocarbons in suspension in surface waters at sections from the English Channel and Skagerak Strait to various regions of the Baltic Sea (2010–2015) and in water and bottom sediments of the southeastern part of the sea in the water area of the Kravtsovskoe field (2008–2015). In recent years, the surface waters of open areas of the Baltic Sea showed a decrease in hydrocarbon concentrations down to background levels (12–33 μg/L). The maximal concentration of hydrocarbons (in excess of the MAC) was recorded in different seasons in navigation areas, including the English Channel and Pregola R. mouth. In the zone of the Kravtsovskoe field, the concentration and composition of hydrocarbons in water depends on their inflow from the bank, and the same characteristics in bottom sediments, on the rate of their leakage from sediment stratum. A decline in these processes have led to a decrease in hydrocarbon concentrations in the sediments of a local area near D-6 platform to background levels (5–7 μg/g) and to the predominance of terrigenous, rather than petroleum, alkanes in hydrocarbon compositions.     

Hydrocarbons in the water, particulate matter, seston, and bottom sediments of the White Sea in the late summer

Aliphatic and polycyclic aromatic hydrocarbons were studied in water, filtration and separation particulate matter, seston, and bottom sediments with the aim to determine their concentrations and origin and compare them with the concentrations of lipids and C_org (August 2006). The effect of anthropogenic hydrocarbons was identified mostly in the Northern Dvina mouth area and in the apex of Dvina Bay. In other parts of the sea, natural compounds dominate in all examined objects, since anthropogenic hydrocarbon cannot pass through the Northern Dvina-the White Sea geochemical barrier. The low temperatures in the high-latitude water areas are shown not to reduce the rate of diagenetic processes in the sedimentary strata.     

Modeling of the marine environmental pollution by petroleum hydrocarbons and their biotransformation in Tatar Strait waters

A hydroecological model is used for simultaneous studying water pollution processes by petroleum hydrocarbons and their decay under the oceanographic conditions of Tatar Strait. The model calculations were based on long-term averaged observational data on interannual variations of water temperature, light intensity, and transparency. Some oceanographic characteristics of the strait were reconstructed with the help of GIS “Sakhalin Shelf.” The strait’s water area was divided into three regions, and water exchange between them and the neighboring regions of the Sea of Japan was estimated by a hydrodynamic model. The results of the study made it possible to assess interannual variations in the concentrations and inner fluxes of petroleum hydrocarbons, oil-oxidizing bacteria biomasses, and the characteristics of their oxidation activity.     

Transformations of biogenic substances in Tatar Strait water (the Sea of Japan): Analysis of mathematical modeling results

The state of the marine environment (the temperature, light intensity, transparency, biogenic load) in Tatar Strait was assessed based on mean annual data from literary sources and with the use of GIS “Sakhalin Shelf.” The entire strait was divided into three regions (northern, southwestern, and southeastern), and water exchange between them for each month was estimated by using Bergen Oceanic Model. The information about the state of the marine environment and water exchange characteristics was used as input data for a hydroecological model, which enabled the assessment of annual variations of biogenic substance concentrations and biomasses of microorganisms (heterotrophic bacteria, three groups of phytoplankton, and two groups of zooplankton) in the strait regions chosen. The development conditions of microorganism biomasses within the year can be characterized by their activity indices (specific growth rates), the values of internal fluxes of biogenic substances, and calculated bioproductivity values. The calculated biogenic substance concentrations and phytoplankton bioproductivity values showed good agreement with the estimates for the Sea of Japan and Tatar Strait available from the literature.     

环太湖各水资源分区入出湖河流总磷浓度与负荷变化分析

入出湖总磷负荷变化是影响太湖湖体磷收支平衡的关键因素.基于2012-2018年水质水量监测资料,计算全湖及各水资源分区河流入出湖总磷负荷,并以水量加权计算其总磷年平均浓度,探明其时空变化规律;运用双累积曲线法分析不同分区水污关系的变化规律;以月为时间尺度,利用Pearson相关系数,揭示入湖总磷负荷分别与入湖水量、入湖...     

Hydrocarbons in the bottom sediments of the Northern Dvina estuary

The results of studying hydrocarbons during the flood in May 2005 are discussed. The concentration of aliphatic and polycyclic aromatic hydrocarbons are shown to match their concentrations in water areas with steady input of pollutants. Weathered oil and pyrogenic compounds dominated in their composition. The geochemical barrier the Northern Dvina River-Dvina Gulf is shown to become a filter during floods and prevents pollutants from penetrating into the White Sea.     

Biohydrochemistry of marine environment and transformations of biogenic substances and oil hydrocarbons on the southeastern Sakhalin shelf

Mathematical simulation is used to study the biotransformation conditions of compounds of organogenic elements (C, N, P, Si) and oil hydrocarbons in the water of southeastern Sakhalin shelf. The input data for calculations were evaluated with the use of Sakhalin Shelf GIS or taken from the reference literature and materials of expedition studies. The values of water discharges through the boundaries of the zones chosen within the shelf water area and through the interface with the Sea of Okhotsk were derived from the characteristics of currents estimated by means of Bergen University oceanic model based on normal long-term monthly thermohaline parameters obtained from the Sakhalin Shelf GIS. The intraannual variations of the concentrations of organic and mineral compounds of C, N, P, and Si, as well as oil hydrocarbons because of biotransformation of substances by organisms of the community (bacteria, phytoand zooplankton) were evaluated in calculations with CNPSi-model. The results of calculations, revealing the features of the dynamics of substances, the biomass of organisms, and their activity in matter biotransformations were analyzed.     

Oil components in the mouth area of the Don R. and in the Sea of Azov: Results of many-year studies

The data given are the results of many-year studying the distribution of the concentrations of main oil components (hydrocarbons, surfactants, and asphaltene-tarry substances) in the water mass, vertically settling particulate matter, and bottom sediment cores taken from the section Lower Don-The Gulf of Taganrog-Russian sector of the Sea of Azov in summer and autumn periods in 2006–2011. Spatial and seasonal regularities in the distributions of the total concentration of oil components and the values of their ratios in water, as well as the spatial and annual features of their accumulation in bottom sediments have been established. Radiological methods have been used for layer-by-layer dating of bottom sediment cores and determine the thickness of the layer that had formed under the maximal anthropogenic impact on ecosystems. The presence of considerable amounts of hydrocarbons of modern biological origin has been revealed in all components of examined aquatic complexes.     

The use of satellite data to characterize phytoplankton in Sea of Okhotsk water

For the identification of natural processes taking place in surface water layer in the Sea of Okhotsk and nearby water areas, satellite data were used to determine seasonal variations of chlorophyll “a” concentration and the problem of water typification by satellite data in the visible light range was solved. Analysis of the annual cycle of phytoplankton concentration variations confirmed the presence of a short explosion in phytoplankton population in the southern Sea of Okhotsk during ice cover formation, which had been predicted before by model calculations. Classes of water reflecting different geoenvironmental situations were identified for characteristic regions of the Sea of Okhotsk. The dependences of chlorophyll “a” concentration growth on temperature were calculated, and corrections were introduced in the standard relationships used in biooptic algorithms for different parts of the Sea of Okhotsk.     

Functioning of the White Sea Ecosystem: Studying the Transformations of Organogenic Substances Using a Mathematical Model

Long-term observational data on hydrology, hydrochemistry, and hydrobiology are generalized and used for systems analysis of the biohydrochemical transformation processes of organic and biogenic substances in a marine environment. An ecological model with the systematized data is used to assess the annual dynamics of concentrations of organic and mineral N, P, and Si compounds and dissolved organic C and O₂ in eight water areas within the White Sea at specified conditions of water mass transport, river runoff, and water exchange with the Barents Sea. Variations in the biomasses of the major transformers of organic and biogenic substances (heterotrophic bacteria, phyto- and zooplankton, and microphytes) and their biological production were also evaluated. These characteristics serve as indicators of the state of the water environment, the presence of nutrients in it, and their import from outside.     

Hydrocarbons in water,sediment and mussels from the southern Baltic Sea

Samples of water, sediment and mussels (Mytilus edulis) from the southern Baltic Sea have been analysed for total hydrocarbons by fluorescence spectroscopy and capillary gas chromatography. The sediment and mussel samples have also been analysed for specific aliphatic and aromatic hydrocarbons by computerized capillary gas chromatography-mass spectrometry. The highest hydrocarbon concentrations in all samples occurred either inshore (particularly in Gdansk Bay) or in deep offshore basins where fine sediment accumulates.     

Analysis of Conditions of Petroleum Hydrocarbon Transformations in Seawater and Simulation of This Process in Aniva Bay

Simulation methods are used to study the self-purification capacity of water from Aniva Bay before the construction on the coast of the bay of the world's largest liquefied natural gas plant and oil loading terminals for ships with a displacement of 100 000 t or more. The calculations are made by using a hydro-ecological model and long-term data on Aniva Bay oceanography. Its water area was divided into five areas, and for these areas, we determined the hydrological and hydrochemical characteristics, evaluated fluxes through their boundaries, estimated petroleum hydrocarbon (PHC) loads, and calculated the annual dynamics of their concentrations and the biomasses of oil-oxidizing bacteria. PHC balances for the five water areas and Aniva Bay as a whole were calculated. PHC consumption by oil-oxidizing bacteria is the most important process of PHC transformation. The discrepancy of the estimated PHC balance in Aniva Bay was found to equal 2.61%, which is within the calculation accuracy.     

The Role of Microorganisms in the Transformation of Biogenic Substances in the Caspian Sea Ecosystem: An Assessment Based on Mathematical Modeling

A hydroecological model is used to study the transformations of biogenic-element (N, P, C, and Si) compounds in different parts of the Caspian Sea. The existing notions of the biotransformation processes of these compounds in the marine environment are formalized. The state of the marine environment is characterized based on calculated annual dynamics of biogenic element concentrations, their relationships, and internal fluxes. Relationships between the concentrations of N and P mineral components are used to establish distinctions between different parts of the sea in the conditions of primary production limited by biogenic elements, as well as the development conditions of aquatic lifeforms (nutrient consumption, release of metabolic products, and detritus formation).     

Downscaling a twentieth century global climate simulation to the North Sea

The regional ocean model system (ROMS) is used to downscale a 26-year period of the twentieth century 20C3M experiment from the global coupled Bergen climate model (BCM) for the North Sea. Compared to an observational-based climatology, BCM have good results on the mean temperature, except for too low winter temperature. This is connected to a too weak inflow of Atlantic water. The downscaling gives added value to the BCM results by providing regional details, doubling the Atlantic inflow, and improving the mean winter temperature. For mean salinity, BCM has values very close to the climatology, whereas the downscaling becomes too fresh. The downscaling, however, improves the sea surface salinity, the vertical structure, and the Norwegian Coastal Current. It is concluded that the downscaling procedure as presented here is a suitable tool for assessing the future Atlantic inflow and sea temperature in the North Sea based on a global climate projection.     

Biotransformation of oil hydrocarbons in Karkinitskii Bay of the Black Sea: Assessment based on mathematical modeling

The transformation conditions of oil hydrocarbons in water are considered for the case of Karkinitskii Bay, the Black Sea, where gas deposits have been developed actively in recent years and oil product pollution of marine environment has been recorded repeatedly. Data on measured oil hydrocarbon concentrations, their input into the northwestern part of the Black Sea, and experimental estimates of oil decomposition in the marine environment are presented. The biotransformation conditions of oil hydrocarbons are simulated by reproducing the biochemical activity of microflora and effecting substrate consumption processes, metabolic product excretions, and biomass decay. These processes maintain the biogenic substance turnover in water environment. The calculations are based on the morphometric characteristics of Karkinitskii Bay, and mean long-term data on the monthly dynamics of marine environmental characteristics (temperature, light intensity, transparency, atmospheric precipitation, and the characteristics of water regime and Danube runoff). A check calculation was performed to reproduce the concentration dynamics of biogenic substances and oil products with allowance made for the effect of river runoff and background pollution of the marine environment. The numerical scenarios take into account the marine environmental pollution conditions (an immediate discharge of 1000, 500, or 200 t of oil products per week) in winter, spring, summer, and autumn. The obtained model estimates of the rates of oil product decomposition and oxygen consumption are shown to agree well with experimental data. The time required for the concentration of oil products to reach the MAC after pollution of the marine environment is estimated.     

Polycyclic aromatic hydrocarbons loads into the Mediterranean Sea: estimate of Sarno River inputs

The polycyclic aromatic hydrocarbons (PAHs) pollution in the Sarno River and its environmental impact on the Gulf of Naples (Tyrrhenian Sea, Central Mediterranean Sea) were estimated. The 16 PAHs identified by the USEPA as priority pollutants and perylene were determined in the water dissolved phase (DP), suspended particulate matter (SPM) and sediments. Total PAHs concentrations ranged from 23.1 to 2670.4 ng L(-1) in water (sum of DP and SPM) and from 5.3 to 678.6 ng g(-1) in sediment samples. Source analysis revealed that PAHs mainly came from combustion process. Contaminant discharges of PAHs into the sea were calculated in about 8530 gd(-1) showing that this river should account as one of the main contribution sources of PAHs to the Tyrrhenian Sea.     

Transformations of Organogenic Substances in the White Sea Ecosystem: Assessment Based on the Results of Mathematical Modeling

Methods of systems analysis and mathematical modeling are used to generalize hydrological, hydrochemical, and hydrobiological observational data with the aim to study the biohydrochemical conditions of organic and biogenic substance transformations in eight water areas in the White Sea. A hydroecological model describing transformations of N, P, and Si compounds and dissolved organic C, as well as the regime of O₂ was used as a means of the study. Water exchange between water areas was evaluated using a hydrodynamic model. Averaged data on annual variations in water temperature, illumination, and transparency, as well as run-off characteristics (water flow in river mouths and organic and biogenic matter concentrations in the river water entering the sea) were used to calculate the dynamics of organic and mineral compounds of nutrients in different areas of the sea. The principal attention is paid to the verification of the model against field observational data, assessment of the biomass development conditions of aquatic animals, analysis of model results regarding the turnover time of organic and mineral components, and the evaluation of balances of organic dissolved and particulate N and P forms.__________Translated from Vodnye Resursy, Vol. 32, No. 4, 2005, pp. 435–451.Original Russian Text Copyright © 2005 by Leonov, Filatov, Chicherina.