فصلنامه اقیانوس شناسی
پیاپی 27 (پاییز 1395)

Malathion is a pesticide that is commonly used in agriculture in Iran and its entrance to the aquatic ecosystems resulting in numerous physiological effects on the fishes. In order to investigate the effect of malathion poison on hematological parameters of rainbow trout, 3 sub lethal concentrations (0.025, 0.05, 0.075 mg/l) and a control (each with three replications) were selected and blood tests were performed on the fifth and ninth days. The exposed fish to sub-lethal concentrations of pesticide malathion resulted in a significant reduction (P

The aim of this research was the comparison of phytoplankton community composition in winter and summer. Also, the phytoplankton composition of the Bardestan creek and its offshore waters in the Persian Gulf were investigated. Samplings were carried out in March and August 2014 by a fishing boat using a Niskin bottle. 9 stations in the creek and 9 stations in offshore waters were selected. Average of phytoplankton abundance was 837 Cell L-1 (±1.65) and 1272 Cell L-1 (±2.86) in winter and 1102 Cell L-1 (±1.95) and 1207 Cell L-1 (±2.45) in summer throughout the creek and its offshore waters respectively. Results indicated no significant difference in phytoplankton abundance between winter and summer (P>0.05). Also, results indicated no significant correlation between phytoplankton abundance with temperature and salinity (P>0.05). Bacillarophyceae, Dinophyceae, Cyanophyceae and Dictyochophyceae were classes of phytoplankton in the study. Cluster analysis revealed that there are three distinct groups of phytoplankton at 30 % similarity level in winter and summer.

In this study, species diversity, density and biomass of two classes of crustaceans (Copepoda and Cladocera) in the shore area of the Babolsar in the three stations (with depth of 5, 10 and 20 m) were assessed in the cold season (February 2015) and the warm season (June 2015). Acartia (Acanthacartia) tonsa from Copepoda and Pleopsis polyphemoides from Cladocera were identified in the collected samples. The highest density and biomass of zooplankton was belonged to A. tonsa which occurred at the stations with the depth of 5 and 10 meters and decreased with increasing depth. The results showed that diversity, density and biomass of zooplanktons were statistically higher in warm season compared to cold season, but their values did not statistically change in the considered stations. The results of this study in comparison with previous studies showed that the diversity of Copepoda and Cladocera in Babolsar shore area was the same as previous years and there were no notable changes observed.

This article aimed to examine and assess the environmental parameters such as salinity, turbidity, temperature and chlorophyll a, using MODIS satellite images, in the coastal waters of the Strait of Hormuz. To measure and estimate the parameters, global algorithms and MODIS data were used. Matrix containing data extracted from satellite images using coding and simulation software MATLAB, were used. Finally, by applying filters in Arc GIS software, these parameters were calculated in the latitudes and longitudes consistent with other marine data. According to the results, the highest coefficient of determination R2= 0.89 was obtained for salinity parameters and RMSE between field data and parameter extraction surface salinity data 0.68, temperature 1.2, chlorophyll a 2.3 and turbidity 1.78 were obtained. Chlorophyll distribution results showed that the coastal areas of the Strait of Hormuz were more susceptible to Chlorophyll blooms than the western and eastern parts.

In order to determine heavy metals contamination in sediment and razor clams from Bushehr intertidal, samples were collected from 5 stations, including Khor Lailatain, Imam Hassan Port, Khor Genaveh, Rig Port and Shif Island. The samples were dried, acid digested and analyzed for their metals content using atomic absorption spectrophotometer. According to the results, the concentrations of Cu, Ni, Pb and Cd in the sediment of the mentioned stations ranged 5.6- 14.75, 19.67-58.72, 7.96-13.92 and 0.68-0.96 μ/g respectively. The concentration of the same metals in soft tissues of razor clam was 5.36-27.84, 0.24-2.72, 5.64-10.04 and 0.32-1.8 μ/g while in the shells they ranged 10.75-21.25, 1.36-3.52, 4.28-8.08 and 0.68-0.96 μ/g respectively. Generally the concentration of the studied metals in both sediment and clams was lower than proposed FAO and USEPA standards

This study was conducted to determine the body shape variation among the populations of the Crested loach, genus Paracobitis, in the southeast Caspian Sea basin using landmark-based geometric morphometrics. In this research, 113 fish samples from Paracobitis genus were sampled from the Tajan, Babolrood, Atrak, Gorganrood rivers in summer using electroshocker. Then, the left sides of the fish samples were photographed by a digital camera. Fifteen landmark-points were digitized on twodimensional images using TpsDig2 software. The obtained results from Landmark data were analyzed and multivariate statistical analyses such as PCA, CVA and cluster analysis (CA) were used and eventually, the Phenotype plasticity patterns of each population related to the shape of overall average of populations were illustrated. The results demonstrated that there was a significant difference among the four studied populations in terms of morphological features (P

The aim of this study was isolating, purifying and molecular identification of associated bacteria isolated from the native sponge of the Persian Gulf that capable of biodegrading crude oil. Dictyonella sp. was collected by diving from the depth of about 10 meters around the Kharku Island. After isolation and purification of associated bacteria, decomposing activity of isolated bacteria was examined in minimal salt medium with crude oil as the sole Carbone source. In order to obtain the extent of biodegradation, the measurement of dry weight and reading the optical density by spectrophotometer were done. The results showed that all three strains isolated in this research had the ability to biodegrade the crude oil and the highest growth rate was related to KE1. Emulsification index for the three bacteria strains isolated KE1, KE2 and KE4 were not significantly different and were (Mean±SE) 37.5± 0.4, 31.45± 0.6 and 36.55± 0.4 respectively. Based on the measurement of dry weight, KE4 strain significantly broke down the crude oil (75.9%). Molecular identification determined that the most similar strains to KE1, KE2 and KE4 with over 90% similarity were Georgenia satyanarayanaiJC82, Pseudomonas rhodesiaeCIP104664 and Gordonia terraeATCC25594 respectively.

Given the importance of biological index in monitoring heavy metals in aquatic ecosystems, in this study, an alga was used as a bio-indicator for heavy metals (lead, zinc, chromium and cadmium) in Karoon River. For this purpose, samples were collected from the dominant alga (Chaetomorpha sp.) as well as from the water and sediments of 6 stations in Karoon River in the summer 2015. After acid digestion of the samples, heavy metal concentrations were measured using Flame atomic absorption spectrometry. The results showed that the average concentration of lead, zinc, chromium and cadmium in water were 2.50, 7.04, 4.32 and 0.28 ppm, in sediments were 26.11, 72.36, 53.14 and 3.68 ppm, and in the tissues of algae were 20.59, 58.08, 37.36 and 1.27 ppm. A significant positive correlation between the concentrations of metals in the sediments of algae tissue showed that the alga (Chaetomorpha sp.) is a suitable bio-indicator for heavy metals in the Karoon River.

Offshore platform is one of the most important and practical marine structures which are always subjected to strong forces resulted from the flow of water, and oscillating loads caused by waves randomly. Because of the complexity, the structure’s conditions and their interaction on fluid, flow pattern and hydrodynamic forces on structures are different, and the presented models and coefficients can’t be used for all situations. Therefore, this study simulated the conditions similar to real conditions of a marine platform in the Persian Gulf using Flow3D numerical model and by geometrical, hydrodynamic and structural information. For this purpose, the model was calibrated in terms of the interaction between wave and structure and hydro-dynamically under boundary conditions and proper reticulated conditions; and percent error of the simulation was investigated and determined under existing conditions. Then, maximum displacement values of the structure’s elements were determined under different height and period conditions using the results of the simulation. According the results of this study, maximum changes of stress in numerical model showed 32% increase in maximum stress values for 25% increase in the height of waves. Also, 50% increase in the height of waves caused 62% increase in maximum stress for the elements of marine platform structure. The changes of maximum stress in the numerical model showed that maximum stress values were increased 16% by 25% increase in the period of waves. Also, 50% increase in the period of waves caused 30% increase in maximum stress for the elements of marine platform structure.

In this study, The effect of different Saccharomyces cerevisia yeast on Growth indices and some of the hematological and immune system of juvenile Acipenser baerii were investigated. 150 fingerling Acipenser baerii with average weight of (32.18±0.51 g) in 15 fiberglass tank were distrubted. Five diets (SR0 SR0.75, SR1.5, Sr2.25 and SR3) containing protein: 45%, fat: 16% and fiber: 3.5% that Saccharomyces cerevisiae supplemented at levels of 0, 0.75, 1/5, 2/25 and 3 g kg-1 were prepared. Fish were fed for 3 percent of body weight in day for 8 weeks. Total fish were biomtry in feeding period in 15 day interval. At the end of feeding trail, blood samples were collected from 30 percent total of population tanks and transferred to laboratory. Final weight and condition factor of fish fed with SR1.5 and SR2.25 were significantly higher than of fish fed diet without yeast (P0.05). Also, amount of lymphocyte and monocyte of fish fed with SR1.5 and SR3 were significantly higher than of fish control (P>0.05). The results of the present study indicated that the supplementation of S. cerevisiae had a positive effect on growth and immune system performance of juvenile Acipenser baerii.