نصرالله محبوبی صوفیانی

In this study, seasonal changes in the diet of Petroleuciscus esfahani and Chondrostoma regium were investigated by collecting 200 samples of each species seasonally in 2013 from the Zayanndehroud River. The indicators of frequency occurrence index, numerical importance index and abundance of benthic organisms were used to determine the importance of food groups. In the current study, 7 classes, 11 orders and 33 families were identified along with other particles including filamentous algae, sediment particles and plant detritius in the intestine of P. esfahani and C. regium, most of which were aquatic insect larvae. The identified groups were related to Annelida (Oligochaeta and Hirudinea), Arthropoda (Crustacea, Insecta and Arachnids) and Mollusca (Bivalves and Gastropoda). The results showed that the highest presence of food groups in the intestines of the P. esfahani was related to Insecta and the least was related to Gastropoda and plant detritius. In the intestines of C. regium in spring, Insects and unknown food groups, in summer, Filamentous algae and Gastropoda, in autumn, filamentous algae and plant detritius, and in winter, Insecta and sediment particles were the most and least abundant, respectively. In general, it can be concluded that Insecta had the highest percentage of importance in both P. esfahani and C. regium, and the diets of these two fish in the Zainderud River are based on feeding on insects.

Phosphorus plays an important role in the growth of algae, production of fatty acids and metabolic processes such as energy transfer and photosynthesis. This study aimed to determine the effect of different phosphorus (P) concentrations on the growth, biomass, phenolic content and antioxidant properties of Microcystis aeroginosa and Anabeana variabilis. After identifying and isolation the desired cyanobacteria, in a completely randomized experimental design was conducted with four different concentrations of Phosphorus in the media, including zero, 0.5, 64 and 256 µgP/L, each in triplicates, using BG11 medium for a 10- day period culture. The average cell density in the treatments of 0 (control), 0.5, 64 and 256 µg/L of P for M. aeroginosa were recorded at 5.2×105, 6.4×105, 10.6×105 and 11.3×105 cells/mL, respectively, for A. variabilis were 2.8×105, 3.4×105, 7.7×105 and 1.4×105 cells/mL, respectively. The amount of total phenolic for M. aeroginosa were 0.5, 1.5, 5.12 and 7.75 mg gallic acid/ DW and for A. variabilis were 4.12, 4.9, 9 and 66.0 mg gallic acid/DW. The DPPH free radical inhibition percentage for M. aeroginosa were equal to 20.51, 22, 23 and 39.23% and for A. variabilis, 25.9, 32.56, 45.12 and 34.1% were calculated. The results showed that the highest growth, photosynthetic pigments and total phenolic as well as antioxidant content were obtained for M. aeroginosa at a concentration of 256 µg/L of P and for A. variabilis at concentration of 64 µg/L of P. Therefore, it can be concluded that the requirement of P in algae is different according to the species, so that each species shows the highest growth rate and other biological activities at a certain concentration of P. Also, understanding the growth of cyanobacteria in relation to the concentration of nutrients in which lead to their bloom is importance for their management of natural water resources, especially fresh and drink waters.

Nowadays, the risk of degradation of wetlands is one of the main environmental challenges in the world, so continuous and long-term monitoring of ecological changes in wetlands can play a key role in their protection and proper management. In the present study, the trend of monthly changes in some of the most important ecological indicators of the aquatic environment of Shadegan wetland including WST, NDVI, MVWR, VWR, LSWI, MNDWI and Chlorophyll-a concentration (during 2003-2017) was evaluated using MODIS satellite imagery. The Mann-Kendall and Sen’s slope tests were used to analyze the trend and its magnitude, respectively. Results showed a significant increasing trend in the volume of water in Shadegan wetland, while the vegetation of the wetland had a significant decreasing trend during the study period (p <0.05). Also, the change in the monthly trend of NDVI, MVWR, MNDWI and LSWI time series was observed around October 2012, which approximately coincided with the development of aquacultural facilities in the northern part of this wetland. In addition, a strong inverse correlation (about -0.86) was observed between vegetation and water indices. Results further provided evidence of an inverse sequence and critical conditions in Shadegan wetland. Integrating remote sensing techniques and statistical methods in this study (to provide continuous time series of ecological indicators) can help to better understand the dynamics of wetland ecosystems (at different temporal and spatial scales). This approach is also applicable in evaluation, modeling and prediction of ecological changes in Shadegan wetland.

Sodium alginate, an anionic polysaccharide, is now considered a new prebiotic due to its immune-stimulating and growth-promoting properties. This study has investigated the effects of sodium alginate on non-specific immune system parameters and growth performance in the rainbow trout fingerling. For these purposes, 90 rainbow trout (3±0.3 g) were fed 3% of body weight with a diet that contain 2.5 g/kg sodium alginate for 45 days. The growth factors and non-specific immune system parameters includes lysozyme, Alternative complement activity (ACH50), bactericidal and respiratory burst activity were investigated in days 15 and 45. At the end of the rearing period, treatments exposed to the toxic dose of ozone. The results showed that the fish feed with diet contain sodium alginate had not significant differences with control treatment on body weight gain, food conversion factor, specific growth rate, condition factor (P>0.05) but there was significant differences in final weight gain (p < 0.05). On both days, 15 and 45, sodium alginate caused the significant increase in lysozyme activity, alternative complement activity, respiratory burst activity and bactericidal of rainbow trout compared to the control treatment (p < 0.05). Furthermore, when the treatments exposed to toxic dose of the ozone, sodium alginate increased relative percent survival compared to the control treatment. According to the results, using of the sodium alginate in diet improved the performance of the  immune system, increased the fish's resistance to the toxic level of ozone and finally increased the relative percent survival in rainbow trout fingerling.

Trophic status of Zayandeh-rood dam water and changes in that were investigated in autumn and winter. Sampling was performed in October, November, January, and February of 2010-11 with 45-d intervals. Nine different sampling points was defined in three different stations, including first three points in lake input, another three points was close to Chadegan village area and the last three points was close to dam crest. Water sampling was done from 30 cm depth of water column in each sampling point by using of Nansen bottle. Water transparency was determined by Secchi disk (1.0-4.30 m), total phosphorus were 0.01-11.57 mg/l, total nitrogen were 0.2-2.20 mg/l and chlorophyll-a were obtained 0-8.84 mg/l in this study. The trophic state index (TSI) was determined for phosphorus 25.22, 33.37, 29.80 and 31.02 at four above-mentioned times. The TSI for chlorophyll a were 44.82, 31.28, 32.37 and 35.14 respectively while this value for Secchi depth was 40.83, 42.42, 50.34 and 48.29, respectively at four sampling time. The obtained appropriate relationship between chlorophyll-a and total phosphorus revealed the important role of this element in algae growth rate while Secchi depth is mainly related to silt particle, washed from ambient land following the raining in these seasons. The TSI mean in all sampling times was 36.5-38.8, showing that the lake can be oligotrophic in autumn and winter. In addition, this lake was an oligotrophic lake based on measured amount of chlorophyll a and total phosphorus in water though the Secchi depth categorized this lake as a mesotrophic.

Mangrove forests are of the most sensitive coastal ecosystems to oil pollution especially to Nickel and Vanadium bioaccumulation. The most important aim of the study was to compare the concentration of Nickel and Vanadium in sediments، mangrove roots and leaves in Nayband Marine National Park and Hara Protected Area in Qeshm Island; as well as to analyze the effects of physical and chemical parameters on these concentrations. So، the correlation between Nickel and Vanadium concentrations with sediment texture، EC، pH، and organic material were analyzed. The results showed that mean concentration of Nickel is higher than Vanadium in sediments and leaves of both habitats. It is also revealed that the mean concentration of both Nickel and Vanadium in sediments and roots in Nayband habitat are higher that those concentrations in Harra habitat which can be because of higher portion of soft texture in Harra habitat. However، the concentration of both Nickel and Vanadium in leaves in Nayband is much higher than of Harra habitat (about 2). This can have to explanations as: first، it might be because of more soluble Vanadium available for transferring to the leaves due to lower EC in Nayband sediments; second، higher exposure and absorption of vanadium from the air because of oil and gas activities in Nayband habitat. These findings are so concerning as usually the conservation، control، and monitoring plans are focused the habitats in vicinity of oil polluted areas but this research showed that also there are the other parameters more than distance-to-source controlling the accumulation of Nickel and Vanadium in mangrove habitats.