جستجوی مقالات مرتبط با کلیدواژه « dissolved oxygen » در نشریات گروه « اکولوژی »

Water is one of the most essential elements in nature that forms the basis of human life and contributes to the economic growth and development of societies. Healthy water is closely related to environmental health and activities. The life of all animals on Earth depends on water and oxygen. In addition, adequate dissolved oxygen (DO) is essential for the survival of aquatic animals. Therefore, in this study, to simulate the dissolved oxygen of the Cumberland River in the United States from the combined artificial neural network (ANN) model with wavelet and meta-heuristic algorithms of gray wolf (GWO) and bat (BA) on a monthly time scale during the statistical period. Used 2020-2010. The criteria of correlation coefficient (R2), squared mean square error (RMSE), absolute mean error (MAE) and Nash-Sutcliffe productivity coefficient (NSE) were used to evaluate and compare the performance of the models. The results showed that all three hybrid models have better results in hybrid models than the other designated models. Also, according to the evaluation criteria, it was found that among the models used in the simulation of dissolved oxygen in river water, the model of artificial neural network-wavelet with coefficient of determination (R2 = 0.958), the root mean square error (RMSE = 0.651), The mean absolute value of error (MAE = 0.334) and Nash Sutcliffe coefficient (NS = 0.962) in the validation stage showed better performance than other models.

one of the problems that threatens coastal ecology is the entry of urban wastewater into the sea by estuaries. Discharge of wastewater into the four estuaries of Bandar Abbas pollutes the coast of the Persian Gulf, which is a priority for the development of management strategies to reduce the risk of pollution. In order to achieve this approach, the present study measured the physicochemical parameters of water and heavy metals in the sediments of the four estuaries of Bandar Abbas, including Sooro, Goursoozan, Shilat and Nakhle Nakhoda estuaries during four seasons in 2019 and Evaluated by pollution indicators. The results showed that the concentrations of DO, BOD, COD, TSS, Cd, Zn, NO3, PO4, detergent and oils in the four estuaries of Bandar Abbas were higher than the environmental standard. The difference in temporal and spatial distribution of water quality pollutants was significant at the level of 95% and its maximum was in Goursoozan and in terms of time in summer, spring, autumn and winter, respectively. The average pattern of heavy metal concentration in the sediments was Zn> Cu> Pb> Cd which mean concentrations was 103.20, 52.55, 19.95 and 0.611 mg/kg, respectively. The maximum metals were in Goursoozan and the evaluation of metal in sediments with Igeo, CF, mdc and PLI indices showed that Cd, Cu and Pb in four estuaries of Bandar Abbas, in the category of moderate to severe pollution. High concentrations of heavy metals indicated the impact of human activities, including the discharge of wastewater into the estuary.

Occurrence of processes such as thermal stratification and nutrition in reservoirs leads to a severe drop in water quality and a lack of optimum levels for various uses and it threatens the life of the aquatic ecosystem. Today, the reservoir of many dams of Iran faced with water quality problems and lowering oxygen dissolution in dehydrated and warm seasons are perhaps the most important negative effects of such reservoirs. Simulation models of Water tank quality are a good tool for predicting water quality, estimating the effects of the contamination of the quantifying the extent and severity of environmental impacts after starting the operation considering the physical and climatic conditions of the reservoir and flow of the river inlet. The studied dam is in the upper reservoir of the Koran Bozan Dam in about 65 km south-east of Kermanshah city. Since there are several sources of pollution on the passage of the river upstream to the dam, the purpose of this study is to investigate the simulation of thermal stratification and soluble oxygen in the dam in line with the environmental studies of the Garsha dam to prevent the damaging effects of dam construction on this region which this study was carried out in 1393. In this regard, at first, the hydrodynamic model of the reservoir of the Garsha Dam was constructed and then calibrated with CE QUAL W2 software and it was used in order to simulate the heat layering and the dissolved oxygen in the dam. The results indicate that thermal stratification is in summer.