Journal of Oceanography
Year:2020 | Volume:11 | Issue:41|Papers Count:14

The purpose of Present study was the effect of resizing of Mesh Size on lenght frequency and weight averages, frequency Kilka Fish Catch in Conical Lift Net May 1997 in Babolsar fishing port by four fishing vessels during 33 torrents at a depth of 50-40 m. After identifying the species caught, the total length and weight of the specimens were measured The results showed that in all 4 nets the highest percentage of fishing frequency was from 11. 5 to 12. 5 cm length range. length range 7. 5-6. 5 in 7 and 9 Mesh Size; . length range 8. 5-7. 5 in 9 Mesh Size; . length range 15. 5-14. 5 in. the length range Mesh Size 7 and 16. 5-15. 5. the length range in Mesh Size Items 7, 8 and 9 were not observed. the length frequency distribution of common Kilka Catch by funnel net was similar to 4 different Mesh Sizes. there was no significant difference between the average length of common kilka Catch with different Mesh Sizes. And the highest frequency in 8mm Mesh Size with an average frequency of 954. the results showed a correlation between the Mesh size and the total length. No significant correlation was found between the Mesh size and total length of common Kilka. Indicates that the Mesh size of the fountain does not determine the total length.

Temperature, salinity, water-level and current speed around brine outflow of desalination site in the Southeastern Coast of Kish Island is investigated. The dominant current is east-west tidal current with a weak residual current which affects current field partially southward. The brine discharge driven hypersaline pollution dispersion is simulated applying MIKE 21, considering three outflow locations at depths of 1, 3 and 6 meters. The seawater salinity affected by brine discharge oscillates similar to tidal fluctuation, but with a phase difference ~180 degrees. The maximum influence from the outflow on adjacent seawater is occurred during neap tide. The outflow mainly moves along the coastline due to the tidal current. The discharge in depth of 3 m, is the optimal location. Finally, the best discharging method is calculated by Jirka (2008)‘ s code which determines the 45° angle between wastewater pipeline-seabed and the creation of 5 diffusers at the discharge position.

Islands and rocks are entitled different maritime zones in international law of the sea. Article 121(3) allocated to rocks has articulated briefly and without indicating any definitions or characters of this feature. Paragraph 3 provided two conditions for rocks in order to create exclusive economic zone and continental shelf zone. The South China Sea tribunal has interpreted this paragraph for the first time and answered some questions such as what does rocks mean? And what is the relationship between rocks and islands and what does human habitation and economic life clauses provided? This article has confirmed some findings of the tribunal and rejected others and reached these conclusions: rocks imply rocky islands. The lack of both human habitation and economic life clauses are needed to deprive rocks of generating broad maritime zones. Tribunal Initiatives like establishing the link between habitants of rocks and economic activities, adding natural condition to “ of its-self” phrase and imposing qualitative standard on “ cannot sustain” are not acceptable based on the text of the article 121 of UNCLOS. The methodology of this research is descriptive-analytical which was done with the help of library source.

Sponge-associated actinobacteria are the prolific sources of marine natural products. The aims of the present study were to propose a process for selective isolation of sponge-associated actinobacteria and to find isolates that produce antioxidant and cytotoxic metabolites. We collected 4 sponge species from the Larak Island, Persian Gulf using scuba diving. The selective isolation process was performed by 4 culture media and 7 physical and chemical treatments. Antioxidant activity of extracted metabolites were evaluated using DPPH radical scavenging activity. Evaluation of cytotoxicity of the extracted metabolites was carry out using brine-shrimp microwell cytotoxicity assay. Out of 114 actinobacterial isolates, 38. 59% was isolated from sponge Dysedia avara. Marine sponge agar medium exhibited maximum efficiency and isolated 44 isolate of actinobacteria. While, most non streptomyces-like isolates were derived by marine zobell agar. Heat treatment isolated 35. 08% of actinobacterial isolates and recovered their most frequency. Approximately, 46 % of the extracted metabolites scavenged more than 90% of the DPPH radicals and their IC50 ranges from 230. 1 to 775. 34 µ g/ml. While, 44% of the extracted metabolites were able to kill more than 90% of the Artemia cells at LC50 range from 236. 3 to 565. 3 µ g/ml. These results represented a selective isolation process for sponge associated-actinobacteria and also could provide an evidence that confirms the active association of the actinobacteria with the Persian Gulf sponges.

As the largest inland lake and one of the most valuable aquatic ecosystems in Iran, Lake Urmia has experienced critical decrease in its water level. Large scale climatological changes in the northwest of Iran as well as the human-involved factors are considered as the main reasons in this regard. On the other hand, by changing the flow conditions in the lake, the need for a thorough study of its hydrodynamic condition is felt more than ever. Therefore, simulation and analysis of waves in the lake have been taken into account. For this purpose, MIKE21 SW is used for wave simulation. Due to the inadequacy and insufficiency of available wind data, numerical model of WRF is implemented. The results of wind simulations indicate significant improvements in predictions compared to ECMWF model and can be considered as final wind data for the implementation of wave model. Also, the results of the evaluations show that the direction of the south-east to the north-west and vice versa are generally two dominant directions for storms over the lake. The results also indicate that the growth of waves follows the wind velocity, and is completely dependent on the water depth. Eventually, wave model studies of the lake can be used as a basis for other related studies such as flow hydrodynamic, water quality and lake ecology studies.

In this research, a modified version of three dimensional hydrostatic finite element QUODDY-4 was used to calculate the spatial variation of bottom friction coefficient in the Persian Gulf. It differs from original one in using an external module for calculation of bottom friction coefficient which was added to the model. Spatial variation of bottom friction coefficient is calculated using a hydrodynamic approach in which relation between wave friction factor and other characteristics of bottom boundary layer is described with non-dimensional parameters like surface Rossby number, Reynolds number for flow and relative inertial frequencies. Results show that friction coefficient varies from 0. 0005 to 0. 006 in the Persian Gulf and in most places, spatially in regions with depth more than 50 meters, its value is less than default value of this coefficient in the numerical models. Consequently, usage of the constant value for friction coefficient in shallow oceanic basins and marginal seas like the Persian Gulf needs attention and special cares.

Harmful algae bloom (HABs; Harmful Algae Blooms), which has been known as a red tide, are in fact an increase in algae species that may produce toxin and directly and indirectly damage aquatic organisms. To identify and investigate the phylogeny of dinoflagellate bloom former species which occurred in November 2017 on the southeastern coast of Iran in the Chabahar port was carried out. In this red tide, Gyrodinium instriatum species was observed with a much lower density compare to the bloom former species. The purification of specimens were carried out under laboratory conditions and the unialgal isolate of the species was incubated in culture room under 12L: 12 D condition and 25 ± 1 º C temperature in f2 culture media. For gene sequencing, DNA was extracted and Polymerase Chain Reaction (PCR) was performed and the gene sequences were determined in the ITS gene region and then compared to the gene sequences of the same species in the Gene Bank. The molecular and phylogenic analysis indicated that the nucleotide sequence of the species with a bootstrap of 99% was most similar to the G. instriatum species. Morphological characteristics confirmed the phylogeny results. The G. instriatum species has a worldwide distribution and potentially a bloom former species, therefore, the exact identification is essential and useful.

The present study aims to provide a bunkering market model in Iran. The research method is qualitative-quantitative. A standard questionnaire form was used to collect data related to measuring research variables. The validity of the questionnaire form was confirmed through its content validity and its reliability was approved according to Cronbach's alpha coefficients. The statistical population of the research in a quantitative stage are managers and experts in the bunkering industry, which selected by simple using random sampling method and due to the lack of access to the community list, the sample size is determined based on the formula 10 to 15 times the questions of questionnaire form. In the qualitative method, which used from interview tool, the statistical population consisted of executive and academic experts who specialize in bunkering industries. In order to study the demographic characteristics of the experts, SPSS 20 software was used and also to determine the codes, main topics and also to present graphic models, Maxqda data analysis software was used. In order to test the model, Amos software has been used and in order to prioritize the factors, AHP has been utilized. The indicators identified in the qualitative method are: motivational support, interaction with customers, appropriate political interactions and communications, interactions with the board members, interaction with employees, distribution capability, promotion, price, product, processes.

The aim of this study is to identify and measure the swimming behaviour of waterflea, (Daphnia sp), parameters in light and control treatments and the effects of environmental light variable on swimming behaviour of waterflea. Aquarium calibrated by the specified spatial coordinated paper plate with dimensions (80×10×30 cm) which are used to determine the measurable behavioural indices and investigated waterflea behavioural parameters in captivity. Behavioural parameters such as number of hops, percentage of absolute dispersion and swimming speed significantly increased in light treatment (P<0. 05). And target swimming speed in the light treatment showed no significant change compared to the control treatment. The results showed that the measured parameters were influenced by the ambient light variables. So that changing ambient light conditions caused change in waterflea swimming behaviour and subsequently the effect on behavioural responses (P>0. 05).

The aim of this research is to identifying and ranking factors affecting on maritime accidents of merchant vessels in high seas Persian Gulf and Oman Sea. Reviwing research literature, factors which are effective on creation of maritime accidents has identified and classified based on view point of experts. Then, using Multi-Criteria Decision Making Techniques, including; AHP, SWARA, and Shanon Entropy, weight and importance of factors has determined. Finally, using Mean Ranking, Borda and Copland techniques, factors final ranking identified. Based on research findings, according to AHP technique, due to weight, factors importance are: human error, environment and route conditions, vessel technical conditions, profession planning conditions, physiological conditions respectively. Based on SWARA techniques, ranking of factors are: Human error, vessel technical conditions, environment and rout conditions, profession planning conditions and physiological conditions. Finally Shanon Entropy technique results show ranking of factors are: human error, vessel technical conditions, profession planning conditions and physiological conditions. At last, using Mean Ranking, Borda and Copland techniques final ranking of factors are: human error; vessel technical conditions; environment and route conditions; profession planning conditions; physiological conditions.

On 4 July 2019, Gibraltar seized oil tanker Grace 1. The Gibraltar`s Chief Minister stated that considering the sanctions under European Council Decisions 255 and 36 including prohibition of the sale, supply and export of equipment, goods and technology which might be used for internal repression of the people of Syria and also the restriction on the purchase, import and transfer of the crude oil from Syria which was imposed for the purpose of the reduction of the financial ability of the Syrian government, the main question of the paper is whether the measures taken by the Gibraltar are legally justifiable.

In this study, Padina pavonica used as a biological monitor of heavy metals on the coast of Bushehr. For this purpose, four stations of Helileh, Lian, Rafael (burned ship) and Naftkesh were selected as sampling sites and sampling of sediment and Algae were done in the summer and winter of 2016. Powdered samples of sediments and algae were digested and analyzed using Atomic Absorption Spectrophotometer. mean metal levels in sediment and algae decreased in the following order: Ni > Pb > Cu > Cd >Hg and showed that the highest metal concentration in algae was for nickel (mean± SE)12. 31± 3. 9 mg/g at Helileh station in winter and in sediment of Naftkesh 11. 45± 0. 65 mg/g. The lowest metal concentration was for mercury in sediment and algeal samples of Naftkesh in winter, respectively 0. 36 ± 0. 005 mg/g and 0. 39 ± 0. 015 mg/g. Also, the highest amount of BSAF belonging to cadmium in Rafael station in winter; that it was 6. 23. The results of this study indicated that this species can use as a bio-indicator for heavy metals in the marine environment.

Asalouyeh is one of the most important oil and gas centers in the southwest of Iran, Bushehr province and on the northern coast of the Persian Gulf. Due to the petrochemical and petroleum industries along the coast, oil derivatives leak into the sea, causing pollution of the water basin in the Asalouyeh area and neighboring areas, which is an environmental threat. The GNOME model is a lagrangian-Eulerian model that is used to find wastewater and contaminated areas. In this paper, to assess the risk of areas affected by the petrochemical effluent contamination of the Asalouyeh coastal area, the refined petroleum effluent diversified under 3 scenarios with Non-weathering materials, Fuel oil 4 and Fuel oil 6 and each in two volumes of 10 and 100, set for 2018. Then, wind and flow were analyzed in the area and applied as input file to the model. Subsequently, GIS-based analyzes were used to map and estimate contaminated areas. GIS output estimates and mapping estimates showed that the highest level of contamination was related to Non-weathering material with an area of 10. 92, which occurred in spring due to increased wind speed and consequently increased water flow. Also, Fuel oil 6 had the highest dispersion, which occurred in the spring. Final results showed that the extent of the contamination with an area of 1. 31 reached to the eastern and southeastern parts of Asalouyeh, the Hala and Hara forest area of Nayband Bay, a national protected area and national park.

Assessing extracted profiles from the Caspian sea bottom between Anzali port and the Sefidrood estuary reveals a sedimentary mass as a source of contingent transitional landslide and so tsunami is located in front of the mouth of the Sefidrood River. In this study, after estimating the characteristic and mass of this contingent landslide, the tsunami caused by this source is simulated using GEOWAVE model. Model outputs illustrate the initial tsunami wave is very high, but damps rapidly as it propagates to the shoreline. The tsunami causes relatively high waves to reach the shores which adjacent to the landslide and creates significant raises. The probability of the tsunami reaching to far and densely populated areas due to the landslide is very low. It can be related to the limited effect of landslide tsunamis due to radial depreciation and dispersion. Therefore, it is concluded the Iranian coasts is safe from the tsunami.