共查询到20条相似文献，搜索用时 31 毫秒
1.
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. 相似文献
2.
Functioning of the White Sea Ecosystem: Studying the Transformations of Organogenic Substances Using a Mathematical Model 总被引：1，自引：0，他引：1
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. 相似文献
3.
T. A. Mikhailik P. Ya. Tishchenko A. M. Koltunov P. P. Tishchenko M. G. Shvetsova 《Water Resources》2011,38(4):512-521
Seasonal variations in biogenic substances (nitrates, nitrites, ammonium, phosphates, and silicates), dissolved oxygen, dissolved
organic matter, chlorophyll, humus, and suspended matter at seven stations on the Razdol’naya River are examined. Based on
seasonal variations, the local sources of river water pollution by biogenic substances were identified. The annual and daily
fluxes of biogenic substances through the Razdol’naya River into Amur Bay are calculated. A diffuse pollution source—agricultural
fields in river valley—are shown to be the main source of biogenic substance fluxes. The vast hypoxia in the bottom water
of Amur Bay, detected by the authors in 2007 and 2008, is supposed to be mostly caused by floods on the Razdol’naya R., which
create favorable conditions of water blooming in Amur Bay in summer. The biomass of dead phytoplankton, experiencing microbiological
decomposition and oxidation, causes hypoxia of bottom waters in the bay. 相似文献
4.
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. 相似文献
5.
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. 相似文献
6.
Residence time of an estuary can be used to estimate the rate of removal of freshwater and pollutants from river inflow. In this study, a calibrated three‐dimensional hydrodynamic model was used to determine residence time in response to the change of freshwater input in Apalachicola Bay. The bay is about 40 km long and 7 km wide, with an average 3 m water depth. Through hydrodynamic model simulations, the spatial and temporal salinity and the total freshwater volume in the bay were calculated. Then the freshwater fraction method was used to estimate the residence time. Results indicate that the residence time in Apalachicola Bay typically ranges between 3 and 10 days for the daily freshwater input ranging from 177 m3/s to 4561 m3/s. Regression analysis of model results shows that an exponential regression equation can be used to correlate the estuarine residence time to changes of freshwater input. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
7.
Water from the Susquehanna River was collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCB) congeners to estimate seasonal and annual riverine loads to the Chesapeake Bay. Temporal variations in the chemical loads resulted from the large changes in the water flow rates and in the particle-associated contaminant concentrations. Concentrations of PCBs and PAHs in river particles (ng/g) were twice as great as those in the northern Chesapeake Bay, indicating that the Susquehanna River is an important source of these contaminants to the bay. The river carries a majority of its hydrophobic organic contaminants (HOCs) in the particulate phase. During periods of high flow, large amounts of suspended particles in the river result in elevated HOC levels and increased loadings of these contaminants to the bay. From 1997 to 1998, 60% of the total annual HOC loading occurred in the early spring coincident with high river flows. The total PCB and PAH annual loadings from the Susquehanna River to the Chesapeake Bay were 76 and 3160 kg/year, respectively and 75% of the loaded organic contaminants were in the particulate phase. Principal component analysis of PAH and PCB congener patterns in the particles reveals that the river suspended particles were dominated by autochthonous production in the summer and by resuspended sediment and watershed erosion during the winter and early spring. 相似文献
8.
Averaged many-year measurement data on the concentrations of mineral forms of biogenic elements are analyzed, and their total concentrations in the rivers of Selenga, Chikoi, Khilok, Uda, Dzhida, and Temnik are evaluated. The monthly variations of the concentrations of major biogenic substances are characterized, and their ratios within a year are determined. Characteristics of river water runoff and biogenic substance concentrations are used to evaluate their within-year discharge by rivers. Characteristic variations in the ratios between the total and mineral forms of biogenic elements discharged by rivers have been revealed. It is established that the share of mineral components in the total input into the Selenga delta Ntot and Ptot are 82 and 22%, respectively. 相似文献
9.
The characteristics of chromophoric dissolved organic matter (CDOM) were studied in Hudson Bay and Hudson Strait in the Canadian Arctic. Hudson Bay receives a disproportionately large influx of river runoff. With high dissolved organic matter (DOM) concentrations in Arctic rivers the influence of CDOM on coastal and ocean systems can be significant, yet the distribution, characteristics and potential consequences of CDOM in these waters remain unknown. We collected 470 discrete water samples in offshore, coastal, estuarine and river waters in the region during September and October 2005. Mixing of CDOM appeared conservative with salinity, although regional differences exist due to variable DOM composition in the rivers discharging to the Bay and the presence of sea-ice melt, which has low CDOM concentrations and low salinity. There were higher concentrations of CDOM in Hudson Bay, especially in coastal waters with salinities <28, due to river runoff. Using CDOM composition of water masses as a tracer for the freshwater components revealed that river runoff is largely constrained to nearshore waters in Hudson Bay, while sea-ice melt is distributed more evenly in the Bay. Strong inshore–offshore gradients in the bio-optical properties of the surface waters in the Hudson Bay cause large variation in penetration of ultraviolet radiation and the photic depth within the bay, potentially controlling the vertical distribution of biomass and occurrence of deep chlorophyll maxima which are prevalent only in the more transparent offshore waters of the bay. The CDOM distribution and associated photoprocesses may influence the thermodynamics and stratification of the coastal waters, through trapping of radiant heating within the top few meters of the water column. Photoproduction of biologically labile substrates from CDOM could potentially stimulate the growth of biomass in Hudson Bay coastal waters. Further studies are needed to investigate the importance of terrestrial DOM in the Hudson Bay region, and the impact of hydroelectric development and climate change on these processes. 相似文献
10.
The impact of Hurricane Ivan on water quality in Pensacola Bay was investigated by MODIS 250 m remote sensing of chlorophyll-a concentrations at different time slots before and after the hurricane event. Before the hurricane, the mean chlorophyll-a in the Bay was 5.3 μg/L. Heavy rainfall occurred during the hurricane landfall. The 48 h rainfall reached 40 cm and the peak storm surge reached 3 m on 9/16. After the rainstorm and during the storm surge on 9/17/2004, the mean chlorophyll-a concentration substantially increased to 14.7 μg/L. 26.3% water area was in the poor-water-quality condition (chl-a > 20 μg/L). This indicates that heavy nutrient loads from urban stormwater runoff and storm-surge inundation simulated chlorophyll bloom. After the end of the storm surge on 9/18/2004, the mean chlorophyll dropped to 2.0 μg/L, suggesting the effective flushing of polluted water from the bay to the Gulf of Mexico by the storm-surge. The good water quality condition lasted for almost several weeks after the storm surge. The peak river flow, arriving on the 4th day after the peak storm surge, did not alter the good water quality situation in the bay. This indicates that urban stormwater runoff rather than the river inflow is the major pollutant source for water quality in Pensacola Bay during the hurricane. 相似文献
11.
The current features of the space and time variations of river runoff in Kamchatka Krai have been considered. Two relatively long cycles have been shown to exist in water runoff variations in the major portion of the examined rivers. The renewable water resources were increasing until 1970–1980, while in the following years (up to 2010), they were gradually decreasing. Current data on river runoff were used to prove the existence of three zonal types of water regime in Kamchatka Krai; five azonal types of annual runoff distribution are characterized. One of them (nearly uniform annual distribution caused by the predominance of groundwater recharge) has been theoretically predicted in the classification proposed by M.I. L’vovich, though without factual confirmation. The specific features of water regime of rivers whose basins lie on the slopes of active volcanoes are considered for the first time. This type of regime typically shows alternating periods of the presence and absence of surface runoff in river channels, corresponding to the inflow of snowmelt or rainfall runoff at high level of subsoil water (when channel deposits are fully saturated with water) or at its low position (when moisture is deficient). 相似文献
12.
Literary data have been used to assess the inflow of petroleum hydrocarbons (with river runoff, precipitation, wastewaters, sea transport, and at ice thawing) into different regions of the White Sea. The hydroecological CNPSi-model was used as an instrument to reproduce the annual dynamics of hydrocarbon concentrations at their parallel inflow and subsequent transformation in the waters of the nine White Sea regions (the bays of Kandalaksha, Onega, Dvina, and Mezen; the Solovetskie Islands; the deep-water part: Bassein, Gorlo, Voronka, and Chupa Bay). The calculations were based on normal annual values of monthly variations of water temperature, light intensity, and transparency, the morphometric parameters of the regions (water areas, mean depths, and water volumes) and water exchange between the regions and with the Barents Sea (calculated by a hydrodynamic model). The calculated concentrations of hydrocarbons, the biomasses and activity characteristics of hydrocarbon-oxidizing bacteria have been analyzed (their values were estimated for the 2-m surface water layer). The results of calculations were used to evaluate hydrocarbon balances for regions and the sea as a whole. The calculations demonstrate the balanced character of hydrocarbon fluxes, the balance discrepancy for the regions being <0.1–16.1%. 相似文献
13.
The data collected for model calculations is systematized for natural and design conditions. The natural conditions did not take into account the effect of the complex of water-protection structures on the hydrological regime of Neva Bay and on the biogenic load onto this water area, while the design conditions, conversely, reflected the possible impact of those structures on the hydrology and ecology of the area. Numerical experiments were used to study the processes of transformation of N and P compounds and the dynamics of dissolved O2 in Neva Bay water area. In the comparison of the calculated and observed concentrations of biogenic substances, Theil criterion was evaluated to assess the adequacy of the model in reproducing the concentration fields of the distribution of biogenic substances over Neva Bay water area. The major qualitative and quantitative features of the formation of the spatial heterogeneity and the time variations in the concentrations of biogenic element compounds over Neva Bay water area are identified. Possible improvements of the model in the reproduction of the complex of processes that are of particular importance for the development of substance transformations in shallow ecosystems are considered. 相似文献
14.
15.
The semi-distributed physically-based model ECOMAG-HM was developed to simulate cycling of heavy metals in large river basins: on the surface, and in soil, groundwater and river water. The model was applied to study the spatial distribution and temporal dynamics of copper concentrations in watercourses of the Nizhnekamskoe Reservoir watershed in Russia. This watershed is characterized by high background concentrations of heavy metals due to wide occurrence of ore deposits and considerable concentrations of ore-parent elements in rocks. The model was found to adequately reproduce the spatial variation of the mean annual copper concentrations at different monitoring points of the river network. The mean annual specific copper washoff, with the surface and subsurface components of river runoff, and the total copper washoff from the watershed into the river network were calculated and mapped. The contributions of natural and anthropogenic factors to river water pollution by copper were evaluated. 相似文献
16.
G. P. Garkavaya Yu. I. Bogatova N. A. Berlinskii V. N. Bol’shakov A. Yu. Goncharov 《Water Resources》2008,35(6):708-715
Long-term observation data were used to carry out comparative analysis of variations in the biogenic matter runoff of the Dnestr River over a period of fifty years. Based on data of weekly monitoring in 2002–2004, annual dynamics of biogenic matter runoff was analyzed for the Dnestr River and for Dnestr Liman. It was found out that, in spite of the “buffer” role of the latter, the contribution of biogenic substances, finding their way in the sea with the Dnestr River water, to the eutrophication of the northwestern Black Sea remains appreciable (about 60 thousand ton year?1). Dissolved organic compounds account for 70% of the present-day biogenic matter runoff of the Dnestr River. 相似文献
17.
This investigation showed that urban stormwater runoff provides a significant amount of petrogenic material to receiving waters and sediments. A characteristic hydrocarbon ‘fingerprint’ for sediments and particulate matter in the Hillsborough Reservoir, Hillsborough River and upper Hillsborough Bay was provided. Determination of source material for petroleum contamination in stormwater runoff and river sediment indicated that crankcase oil was a primary contributor to sediment hydrocarbon contamination. A comparison of sediment hydrocarbons with hydrocarbons from stormwater runoff showed that the most probable source of crankcase oil-like petrochemicals found in sediment was the stormwater runoff.A comparison of hydrocarbon composition in suspended particulate matter with that of accumulated bottom sediments in the reservoir, river and bay, during a non-storm period and rising tide showed no resuspension and upriver transport of petroleum contaminated bay sediment. No special influence of the bay upon the lower river was observed relative to hydrocarbon tracers, indicating that most contaminated sediment transport was downriver during storm events. Additional studies should be performed over various tidal cycles and storm events incorporating sediment cores, sediment grain size analysis and hydrocarbon characterization at more closely spaced stations near the river mouth to address adequately the question of specific hydrocarbon pollution sources, rate of petroleum influx and persistence of petrochemical contaminants in the sediment. 相似文献
18.
Regularities of the formation of biogenic elements flow and water quality in the Istra River (downstream of the Istrinskoye Reservoir) and its tributaries are revealed. Temporal variability in water quality parameters is shown to be closely related to fluctuations in the river water abundance, whereas spatial variability is determined by different intensity of anthropogenic load on river watersheds. It was found that the mean annual (for the period of 1991–1995) concentrations of nitrogen and phosphorus mineral compounds do not always meet the requirements of drinking water supply. A method of estimating the environmental state of the main river, taking into account biogenic elements input from its basin is suggested. 相似文献
19.
The article presents the results of hydrochemical studies of two areas, open and closed, in the littoral zone of Lake Onega, carried out in 2013–2014. The results show that water of river and slope runoff, enriched with both biogenic elements and allochthonous organic matter, persist over a long time in spring in the littoral zone. In the summer, water chemistry at open shores is similar to that in lake pelagic zone, while the closed areas of littoral zone show the effect of biological processes. In the period of autumn homothermy, river and slope waters have no considerable effect on coastal water quality. 相似文献
20.
Huai River Basin, as the sixth largest river basin in China, has a high‐regulated river system and has been facing severe water problems. In this article, the changing patterns of runoff and precipitation at 10 hydrological stations from 1956 to 2000 on the highly regulated river (Shaying River) and less‐regulated river (Huai River) in the basin are evaluated at the monthly, seasonal and annual scales using the Mann–Kendall test and simple linear regression model. The results showed that: (1) No statistically significant trends of precipitation in the upper and middle Huai River Basins were detected at the annual scale, but the trend of annual runoff at Baiguishan, Zhoukou and Fuyang stations in Shaying River decreased significantly, whereas the others were not. Moreover, the decreasing trends of runoff for most months were significant in Shaying River, although the trend of monthly precipitation decreased significantly only in April in the whole research area and the number of months in the dry season having significantly decreasing trends in runoff was more than that in the wet season. (2) The rainfall–runoff relationship was significant in both highly regulated river and less‐regulated river. In regulated river, the reservoirs have larger regulation capacity than the floodgates and thus have the smaller correlation coefficient and t‐value. In Huai River, the correlation coefficients decreased from upper stream to downstream. (3) The regulation of dams and floodgates for flood control and water supply was the principal reason for the decreasing runoff in Huai River Basin, although the decreasing precipitation in April in this basin was statistically significant. The findings are useful for recognizing hydrology variation and will provide scientific foundation to integrated water resources management in Huai River Basin. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献