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Showing 3 results for Water Salinity
, Mahmoud Nafisi Bahabadi, , , ,
Volume 5, Issue 2 (9-2016)
Abstract
In the current study, the effect of fresh water and different salinities of 15, 35 and 50 ppt on growth, feeding, body composition, glucose and cortisol in Asian sea bass (Lates calcarifer); were investigated. 180 fingerlings with average weight of 34.36±0.41 gram in 12 circular fiberglass tanks with 300 liter volumes were administered. Feedinng was done to satiation twice a day for 30 days. At the end of the experiment, biometry carried out and plasma and carcass samples were collected for estimating blood biochemical parameters and whole body composition. The obtained results showed that freshwater treatment had a significant difference in growth and feeding performance with other treatments (p < 0.05). Also, the results of carcass analyze showed that freshwater treatment moisture percentage was significantly higher (72.07±0.11) compared to other treatments (p < 0.05). Glucose and cortisol value in 15 ppt treatment were significantly higher at 35, 50 ppt treatment and 35 ppt, freshwater treatment, respectively (p < 0.05). Overall, this study showed this species is able to tolerate changes in salinity in the surrounding medium from seawater to brackish water through a period of 30 days and successfully adapt to freshwater without showing mortality. But, it could not be a good case for culture in fresh water because of using high energy for osmoregulation in fresh water.
Volume 19, Issue 4 (7-2017)
Abstract
This study aimed to detect possible strategies used by olive (Olea europaea) and pistachio (Pistacia vera) species under saline conditions to be considered in early selection programs of salt-tolerant genotypes. One-year-old seedlings were irrigated alternatively with ½ Hoagland nutrient solution and distilled water added with 0, 75, or 150 mM NaCl during 3 months under controlled conditions. Growth, leaf toxicity symptoms, and shoot and root mineral compositions were assessed. Salt induced leaf injury and a significant decrease in growth of both species seedlings. The decrease in shoot elongation was more pronounced on pistachio seedlings, whereas leaf formation and plant fresh weight showed greater reduction on olive plants. Pistachio seedlings developed new axillary shoots and leaves at 75 mM NaCl. The root fresh weight was significantly reduced by salinity in olive, but remained unaffected in pistachio. Both saline treatments induced leaf fall with more pronounced effect on olive plants. Olive salt tolerance may be associated to a better control of Na+ accumulation in the leaves and its ability to accumulate potassium in shoots in order to achieve osmotic adjustment. Pistachio seedlings seemed to better control Cl– ion ascension from roots to shoots through salt ion dilution mechanism. The increase in root fresh weight of pistachio seedlings at both salt treatments and the higher ability of this species for uptake of calcium (involved in the regulation of stomata movement) seem to support this hypothesis.
Volume 24, Issue 5 (11-2024)
Abstract
The semi-closed geometry of the Persian Gulf and its location in a dry and desert area have caused evaporation as one of the most important climatic parameters affecting the water salinity and water exchange between Oman Sea and Persian Gulf. Since the global warming as well as the decrease of precipitation will increase the evaporation in future, it is very important to investigate the effect of this phenomenon on the salinity of the Persian Gulf and its effect on the facilities, especially the desalination plants in the Persian Gulf. Therefore, this research have been carried out with the aim of investigating the circulation of water in the Persian Gulf and evaluating the direct effect of water evaporation on salinity and water exchange with the Sea of Oman. In this regard, the hydrodynamic modeling by considering the effect of evaporation in the Oman Sea and the Persian Gulf has been done using the three-dimensional Mike3-Flow Model.
The input hydrodynamic data is extracted from the HYCOM model and the required atmospheric data is extracted from the ECMWF model. To evaluate and validate the model, numerical results have been compared with TPXO data and tidal levels by means of statistical parameters. The results of this study show that the amount of cumulative water entering the Persian Gulf has a relatively linear relationship with the percentage of evaporation. Also, the increase in water evaporation from the surface of the Persian Gulf has a strong effect on the salinity of the Persian Gulf, and this effect is widespread but variable in the surface of the Persian Gulf, so that the areas closer to the Strait of Hormuz are less affected by the increase in evaporation, and the increase in salinity in the shallow northern as well as in the southern coasts have caused an increase in the average salinity of the Persian Gulf. On average, a 50% increase in evaporation increases the water salinity by 3 psu and a 100% increase in evaporation causes an increase in water salinity by 6 psu.
