علوم زیستی دریا
Shahla Hamid; Faedeh Amini; Solmaz Shirali; Kamal Ghanemi; Ahmad Shadi
Abstract
In this study, the amount of heavy metals (nickel, cadmium, lead, copper, mercury) in brown algae Sargassum sp., Padina sp. and Cystoseira sp., sediments and the amount of mercury in water were also measured. ampling was done during winter 2016 and summer 2017 at four stations from the shores of Bushehr.Analysis ...
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In this study, the amount of heavy metals (nickel, cadmium, lead, copper, mercury) in brown algae Sargassum sp., Padina sp. and Cystoseira sp., sediments and the amount of mercury in water were also measured. ampling was done during winter 2016 and summer 2017 at four stations from the shores of Bushehr.Analysis of heavy metals in sediments and algae after chemical digestion and preparation was investigated by Savanta model atomic absorption spectrophotometer. The order obtained from the concentration of heavy metals in Padina sp. cadmium > lead > nickel > copper > mercury, for Sargassum sp. as lead > copper > nickel > cadmium > mercury and for Cystoseira sp. It is in the form of copper > lead > nickel > cadmium > mercury, among which Padina sp algae had the highest accumulation of heavy metals. The order of concentration of metals in sediments was nickel > lead > copper > cadmium > mercury. All metals, except for lead metal, have a higher average in the summer season, and the average mercury metal in water was measured at 0.23 micrograms per gram of dry weight. Correlation results showed that the concentration of heavy metals (nickel, cadmium, lead, copper, and mercury) in macroalgae Padina sp, Sargassum sp, sp. Cystoseira and their adjacent sediments in the shores of Bushehr, two algae Sargassum sp. and sp. Cystoseira have a greater ability to accumulate heavy metals.Cystoseira have a greater ability to accumulate heavy metals. According to the obtained results, the concentration of heavy metal mercury in the waters of the shores of Bushehr city with its amount in the studied algae, it seems that Sargassum sp. It is a suitable material for biological monitoring of this metal in the study area.
علوم زیستی دریا
Sanaz Ahmadi Falehi; Ahmad Savari; Nasrin Sakhaei; Faedeh Amini; Babak Doustshenas
Abstract
Planktonic crustaceans are of specific importance in energy transfer due to their location in the middle links of the food chain of aquatic ecosystems. Therefore, they directly affect the abundance and diversity of the higher categories of the food pyramid, especially stocks and fishery resources. In ...
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Planktonic crustaceans are of specific importance in energy transfer due to their location in the middle links of the food chain of aquatic ecosystems. Therefore, they directly affect the abundance and diversity of the higher categories of the food pyramid, especially stocks and fishery resources. In this study, the impact of a tidal cycle on the zooplanktonic Crustacean ecosystem in the estuarine Bahmanshir River (Northwestern Persian Gulf) was studied. Our samples were collected during the spring of 2018 by plankton net with mesh sizes of 100 μm. Samples were taken at 5 stations to have a tidal effect on the abundance of zooplankton, approximately from 8:00 to 18:00 every two hours. In general, 72 species belonging to 28 families related to 3 groups of crustaceans named Cirripedia, Cladocera, and Copeoda were observed. The highest percentage of relative abundance was related to Cladocera with 35%, which was caused by the abundance of Daphnia mendotae. The highest diversity (Shannon index = 2.71 ± 0.04) of copepods was revealed to be caused by the large number of species at station 5 (near the mouth of the Bahmanshir River). Most species among the families belong to the Acartiidae family, which has 10 species of Acartia. The results of PCA analysis showed that among environmental factors, salinity has a direct effect on the total density, density of Harpacticoida and Calanoida, in the first component. The tides appear to significantly affect the density and types of planktonic crustaceans during the mentioned springtime periods. Our results showed relatively strong influence of the tidal cycle on the spatial pattern of Copepod assemblages in the study area. This study may be useful for future biological monitoring and seawater salinity intrusion into rivers in the northwest of the Persian Gulf.
علوم زیستی دریا
Seyyed Kiarash Jafari; Ahmad Savari; Faedeh Amini; Hosseim Mohammad Asgari
Abstract
The international Shadegan wetland is one the biggest ponds in Iran and located in Khouzestan province.This wetland is with more than 530 thousand hectares vast wetland registered in the international Ramsar Convention.Climate changes can make negative or passitive conditions by drought or wet periods ...
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The international Shadegan wetland is one the biggest ponds in Iran and located in Khouzestan province.This wetland is with more than 530 thousand hectares vast wetland registered in the international Ramsar Convention.Climate changes can make negative or passitive conditions by drought or wet periods on water quality and volume of this wetland.Today, concerns about the warming of the earth and damage to vital natural resources, have led researchers to study different periods of drought. Drought is a phenomenon adverse impact on all ecosystems, including wetlands. Because of it, new drought indices should be associated with specific time scales for monitoring and management of water resources. In the study area, data required by the Metrological Agency, water and power authority and by ocean-atmospheric data from NOAA satellites from 1950 to 2015 (65 years old) received. Changes in wetland on the downside and upside of drought and wet were studied by standardized precipitation evapotranspiration index (SPEI). The final model showed decaying and destroying the wetland each year goes by drought from year of 1998.