جستجوی مقالات مرتبط با کلیدواژه "trophy" در نشریات گروه "اکولوژی"

Today, the environmental and habitat importance of wetlands has been revealed for all societies and special attention is paid to urban wetlands for recreation, boating, fishing, hunting, and aquaculture. One of the most important natural-man-made wetlands of Gilan province is located in Lahijan city and is called Lahijan pool. The objectives of this research were to investigate and identify the phytoplankton, zooplankton, and aquatic communities of this wetland in five stations and during four seasons. From the fall of 2017 to the summer of 2018 in this habitat, which has an area of ​​11 hectares and a depth of less than 4 meters, planktons and crustaceans were sampled by standard methods and the results showed that the average water surface temperature was 17.16 ± 7.3 degrees Celsius, dissolved oxygen The water level was 7.05 milligrams per liter, the pH of the water depth was 3.85, and the average percentage of organic matter was 3.29 ± 1.26. Phytoplanktons was identified in 7 branches and 29 genera, and in terms of annual abundance, blue-green algae ranked first with 48% and Bacillophyta ranked second with 43%. 4 groups and 18 species of zooplankton have been identified in this ecosystem, of which pinnipeds were the most abundant with 35%. Oligochaeta and Chironomide larvae were the only identified benthic groups that had 167 numbers per square meter. In general, the species diversity of plankton and crustaceans in this wetland was low, but the density of the present species was determined to be relatively high. According to the physicochemical characteristics of the water and the planktonic and benthic species of this lagoon, it should be considered a eutrophic ecosystem, but of course, the input and output of water and the aeration that takes place in it can create the conditions for the breeding of some tropical fish or crabs. Make fresh water possible.

One of the phenomena that lead to the deterioration of surface water quality specially reservoirs is eutrophication caused by nutrients increasing like nitrates and phosphates in water resources. In this study, nitrate, phosphate and other factors such as temperature, turbidity, biological oxygen demand were measured monthly in six stations during the years 1393-1394 and the status of eutrophication in Kani-Brazan wetland and its influencing factors were investigated. The concentration of phosphorus and nitrogen of the wetland water were classified to the fourth trophic level of Oligotroph, Mezotroph, Eutroph and Hypertroph, and by comparison with international standards of Nuremberg, wetland eutrophication status was determined. Results showed that the average annual value of the water temperature was 17.4°C, pH=8.02, turbidity=16.03 and BOD was 5.8 (max=8.2 in spring and min=6.9 in summer). The values of all forms of nitrogen varied between 0.4 to 0.8 mg/lit indicating the trophic health of the wetland. The amont of phosphorus in wetland was upper than the limit of 0.03 mg/lit indicated that continue of this process could have consequences for the wetland ecosystem and affects attractive aquatic environment greatly.

Amirkelaye international wetland, with an area of 935 acres is located in Gilan province. Agricultural runoffs, water withdraws for agricultural purpose and plants growing, especially submerged and marginal plants are of the main threatening factors in this wetland which reduce its surface and therefore it is necessary to determine the trophy status in the case of adverse circumstances, the reclamation measures can be done for it. The research was made from autumn 1392 to summer 1393 in order to check the status of Amirkelaye wetland trophy. Sampling was done from 6 stations during four seasons, and in which trophic state index (TSI) was examined using 4 parameters: total phosphorus (TP), total nitrogen (TN), the depth of Secchi disk (SD) and chlorophyll (chl-a). According to TSI index, Amirkelaye wetland is in the most critical state in the terms of SD parameter compared to TP, TN and chl-A parameters and in a better state in terms of chl-A parameter compared to TP, TN, and SD parameters. According to the statistical analysis, the average amount of total nitrogen in winter and summer was lowest and highest, respectively. The average amount of phosphate was observed as highest and lowest in winter and autumn, respectively. Average amount of chlorophyll A was highest in summer, but the other three seasons together in terms of the amount of chlorophyll A were not significantly different (P> 0.05). Average depth of Secchi disk was found the lowest and highest in summer and winter, respectively. Using Duncan statistical test, none of the variables of chlorophyll A, total nitrogen, total phosphorus and depth of Secchi disk at various stations were significantly different (P> 0.05). The results showed that in the autumn and winter, Amirkelaye wetland was in the Mesotrophic state and in the spring due to agricultural runoffs entering was in acute Mesotrophic state. In the summer, due to increased agricultural runoffs entering and the hot weather, it was in the Eutrophic state.