فصلنامه اقیانوس شناسی
پیاپی 42 (تابستان 1399)

Breakwaters are among the most frequently-used coastal protective structures and their stability is vital to avoid turbulence at the ports. The main purpose of the present research is to use the theory of fuzzy random variables and the second-order reliability method (SORM) to study the reliability of a rubble-mound breakwater against the failure due to the armor layer instability. The limit-state function used for the reliability analysis is obtained from van Gent stability equation for two different modes of wave breaking: plunging and surging. The data used in this research are extracted from the western branch of Anzali Port breakwater. First, a fuzzy inference system (FIS) has been created using MATLAB and the results have been provided including surfaces between random variables with respect to limit-state function and cumulative distribution of each random variable. Afterwards, the formulation of limit-state function, sensitivity study, and second-order reliability analysis have been implemented using Rt software and the final results are presented including variable inference, correlation coefficients, probability of failure, reliability index, sensitivity and importance measures and sensitivity of probability of failure and reliability index with respect to changes in moments of each random variable.

Heavy metals are one of the most important organic pollutants in the environment due to human activities in the environment. This study was carried out to investigate heavy metals in 7 stations of Hur al-Azim wetland in the spring of 2018. The statistical population for measuring heavy metals such as Ni, Pb and vanadium with 3 repetitions included 21 sediment samples, 21 water samples, 21 samples and 21 Mesopotamichthys sharpeyi (Beni)fish samples. In sediments, nickel element with an average of 28.56 ± 9.18 mg / kg has the highest concentration , vanadium and Pb with values of 21.57± 8.35 mg / kg and 2.74± 1.82 mg / kg were placed in the following ranks (P <0.05). In water, the concentration of lead and nickel metals had the highest concentration between 0.13 - 0.11 and 0.12 - 0.11 mg / l, respectively, and the vanadium in water at Station 7 with 1.08 mg / L concentration (P <0.05) and vanadium were higher than nickel and lead concentration (P <0.05). Vanadium, with an average concentration of 1.26 (range 0.90-2.50), had the highest concentration of 1 mg / kg in the Phragmites (P <0.05) and, except in the Phragmites, two stations 2 and 3, with Ni and Pb had higher concentration respectively, and vanadium had the highest concentration in other stations (P <0.05). In the muscle of Mesopotamichthys sharpeyi (Beni) fish held from station 7, lead and vanadium metals with values of 52.1± 08.0 and 0.71± 07 mg / kg and Ni with a value of 0.54 ±0.04mg / kg in the station 5 had the highest value (P <0.05). Hur al-Azim wetland sediments showed low ecological risk in terms of values of ecological pollution index. A comparison of the low concentrations of metals in the Mesopotamichthys sharpeyi (Beni) fish muscle with the WHO and NHMRC standards showed that the fish muscle was unhealthy in terms of nutrition. There was a correlation between the concentration of heavy metals in the sediment chain, water, Phragmites and fish, and sediment and Phragmites were the main storage of heavy metals in the wetland.

This research for introduce and paleontology of Early Cretaceous Rudist in the Middle Tethys Ocean, stratigraphic section of the kalleh pahnoo has been selected from the Shahkouh Formation in Central Iran (Khor and Biabank region). The studied section consists of 120 m thin layer to massive limestone. Studies on 106 specimens collected and prepared from this section have led to the identification of specimens from the Hippuritoid class. Overall, 2 genera and 5 species of Radiolitidae family and 1genera and1 species from Requienidae family were identified. According to studies age of Kalle pahnoo deposits, late Aptean-Albian was suggested. Paleoecology studies on growth form and shapes of rudist communities indicate relatively warm environment with low salinity in this region. elevated rudistschr('39') morphology revealed a relatively calm and quiet environment, with continuous deposition.

In order to investigate the sedimentary texture, diversity and density of benthic molluscs, 55 stations at 9 transect were collected in the Nayband Bay.Samples were taken with a Van Veen grab (0.022 m2) in 3 replications in each site.Using a Particle Size Analyzer instrument revealed that the sediment texture was dominated by sand with 7 sub distinct sub sediment. Semelidae,Veneridae and Tellinidae families belonged to bivalves were dominant families in all identifeid molluscs. In this region,sediment particle size and depth variations had significant effects on species distribution, richness and eveness.The diversity, species richness and abundance of Mollusc increased with depth Increasing.The mean value of Margalef and Shannon index interpreted the study area as contaminated region while the Pielu index described the environment without stress.

Countries which are benefited from the sea and marine resources are trying to provide proper infra-structures to use the advantages of the seas. Ports, undoubtedly, are the primary and the fundamental infrastructure of every country in the field of marine economics. Governments all over the world spend huge funds on designing, building, and maintenance of these structures. According to the recorded data and field observation, a severe storm in January 2019 occurred in Caspian sea and caused some damages to some parts of the Caspian Port Complex breakwaters which had been constructed at that time. This research with the aim of determining the causes of these damages was carried out to model the aforementioned storm via the SW module of Mike 21 software. Before the modeling, a comprehensive study on the former models of forecasting the specific characteristic of the waves of the studied area had been performed. Results showed that in spite of the fact that the significant wave height considered for designing the profiles was underestimated in calculations, this characteristic during the storm was not higher than the calculated one. Consequently, overtopping phenomenon and lack of the final cover at the top of the breakwaters during the storm were responsible for the partial damages.

The main purpose of this study is to provide a model for identifying managerial characteristics affecting the development of non-oil exports and intends to test this model in Iranian exporting companies in the aquaculture industry by mixed method (qualitative-quantitative) and by examining 38 exporter firms. Interviews and questionnaires were used to collect data and were analyzed by thematic analysis method, fuzzy Delphi technique, structural-interpretive modeling and at least partial metaphors technique. Sampling in the qualitative part was Purposive sampling and in the quantitative part of the research was done by stratified random method and among the exporting companies of Tehran, Bushehr, Hormozgan, Mazandaran, Golestan and Gilan provinces, they were selected as a statistical sample. The research findings in the qualitative section led to the identification of 6 main managerial factors and in the quantitative section, the findings were confirmed and led to the prioritizing of managerial characteristics affecting the development of sustainable exports. The results also indicate that among the identified factors,; Managementchr('39')s approach to new marketing movements, managementchr('39')s approach to new strategies, and managementchr('39')s approach to inter-firms relations have had a greater impact on export performance of exporting companies than other variables. Finally, based on the findings of the research, the final framework is presented in this field, which has led to the presentation of a typology of management factors affecting the development of sustainable export performance.

Dietary cholesterol has been shown to be essential for several crustacean species. However, cholesterol requirement of narrow-clawed crayfish has not been reported. Therefore, a 12-week feeding trial was conducted to determine deitary cholesterol requirement of narrow-clawed crayfish. Juvenile crayfish with an average body weight of 13.8±1 g mean weight were intensively stocked in an indoor recirculating aquaculture system consisting of 12 rectangular fiberglass tanks with 10% daily water exchange under constant aeration and PVC shelters. Water was recirculated through biological and mechanical filters. Four experimental diets with 30% crude protein and 10% crude lipid were formulated to contain graded levels of dietary cholesterol (0, 0.25, 0.5 and 0.75 % Cholesterol). Casein and gelatin were used as primary sources of dietary protein in experimental diets. Our results showed crayfish fed diet with 0.5 and 0.0 % cholesterol level produced the highest and lowest growth indices, survival rate and enzymes activity including protease, lipase and amylase, respectively significant (P<0.05). With increase of cholesterol content of experimental diet (0.75 %) crayfish survival rate and lipase activity siginificantly decreased, however, no significant differences were observed regarding growth indices, protease and amylase activity (P>0.05). In conclusion, the results indicated that dietary inclusion of 0.5% cholesterol would improve growth performance and digestive enzymes activity of juvenile narrow-clawe crayfish reared under intensive condition.

The WRF model is simulation system and heavily dependent on computing, I/O, and network and running it on the fastest computers is a major challenge. Optimal and timely implementation is the goal of many meteorological organizations. The management and implementation of high-performance computing applications is mainly based on cluster and cloud computing infrastructures due to the highly coordinated, consistent, and parallel processing of large data in them. These infrastructures typically use virtualization to manage access to resources. The purpose of this research is to use Containers as a lightweight virtualization to implement the WRF model, which provides a very small overhead for resources in the cloud infrastructure. Model implementation scheduling enables organizations to perform forecasts periodically, sometimes several times a day, and increase model members to obtain better output. To calculate the runtime of the model at different geographic scales on a software and hardware platform a mathematical formula is proposed.

In this study, Artificial Neural Networks (ANN) has been used for reducing the errors of sea wave model predictions. Firstly, stand-alone PMODynamicsI model has been implemented to predict Bushehr deep-water wave characteristics. Results implies that PMODynamicsI performed better in simulating ordinary wave with height less than 1m, but it is underestimated about 75cm related to a weak  wind Global Forecasting System (GFS) forecasts during east and southeast storms. In order to increase the wave model accuracy, a MLP ANN system consists of three layers of nodes has been defined to predict the wave model errors, which optimal selection of a number and type of input neurons among factors influence the formation of "wind waves" has helped to find the relationship between input and output in ANN to minimize model error. The combination of PMODynamicsI together with ANN technique has been improved the accuracy of the sea wave model forecast till %90 and reduced RMS error from 0.31 in stand-alone PMODynamicsI to 0.22 in combinations models. As a result of the use of combined wave and ANN systems makes accurate predictions for extreme wave about 60cm.

The present study was conducted to study the morphology of the symbiotic Zooxanthellae with an anemone of Stichodactyla haddoni. Sampling of the sea anemone was carried out in the east coast the Island of Hormuz during a full tide in summer of 2015. The samples were placed in a nitrogen tank and transferred to a laboratory in the shortest possible time. Extracting and counting the Zooxanthellae cells which coexist in symbiosis with the sea anemone were made with an electrical homogenizer. The stages of preparation and fixation of samples were conducted by glutaraldehyde 3%, alcohol and acetone and then the Zooxanthellae cells were examined with the optical microscopes of HP31 and Zeiss and an the electron microscope. The results of the study showed that, firstly, Zooxanthellae can be multiplied only by mitosis in coexistence conditions. Secondly, it is known that the cells of one species should be approximately one size, but the size of some cells, which were extracted, were considerably different from other. Therefore, it is possible to assume that the studied anemone of Stichodactyla haddoni included more than one species of the symbiotic Zooxanthellae in the investigated time.

The Caspian Sea, as the largest lake in the world, has always been one of the most important regions of the world. Technological advances and, as a result, increasing coastal stateschr('39') access to its living and non-living resources have added to its economic and strategic importance. With the collapse of the Soviet :union: and the increase in the number of Caspian coastal states from two countries to five, the issue of access to the Caspian Sea and the exploitation of its existing resources has taken on new dimensions.
Today, the most important issue in the Caspian Sea is the legal regime that governs it and the issue of delimitation that precedes other issues. The present article uses descriptive-analytical and library-based approaches to examine developments in the legal regime of the Caspian Sea from the 1921 and 1940 conventions to the most recent one, the 2018 Actau Convention.Given the relatively different areas defined by the Actu Convention in relation to the 1982 Convention on the Law of the Sea and some terms and terminology generally used, the present article is concerned with international jurisprudence and principles of the law of the sea. It has, to some extent, provided analysis for their explanation.

The oceanic facies in the Southwest of Iran (Neo-Tethys), deposited between Iranian and Arabian blocks. In this study, the part of this oceanic facies have been investigated in the upper part of the Gurpi Formation and lower part of the Pabdeh Formation at Shalou section, located in southeast of Izeh. In this section, the Gurpi Formation is mainly composed of green and dark gray shale and lower part of the Pabdeh Formation consists of purple shale. For introducing index species, calcareous nannofossil assemblages and bio-zones, 82 slides have been studied at the facies which led to the recognition of nine bio-zones. As a result, 41 species and 27 genera of calcareous nannofossils According to the identified bio-zones, the age of studied section is late Maastrichtian to late Paleocene (Thanetian) and K/Pg boundary is continuous at the studied interval, that is corresponding to CC25 - CC26 , and subsequently NP1- NP7/NP8.

Polychaetes are ecologically important in the food chain, and also vital in ecosystem monitoring and environmental stress assessment. In the current study, sequence variation in a segment of COI gene sequencing by mitochondrial DNA barcoding and comparing nucleotide divergence was employed for molecular analysis of Perinereis polychaetes (Nereididae). Analysis of 50 sequenced specimens, representing 39 new sequences, and 11 sequences with 100 percent similarity with GenBank records, which revealed 1.8 times more sequence divergence between than within species (1.96 versus 3.52%). Phylogenetic analysis data indicated that maximum divergence within barcode clusters increased by the number of specimens. The phylogeny also suggests that most of the identified Perinereis species in this research showed low genetic relationship towards similar species from other world regions. Assessment of genetic similarity rate showed that Perinereis polychaetes in Bushehr province were highly similar, while Perinereis polychaetes in Bandar Abbas were less similar to Bushehr Perinereis polychaetes, the observed divergence was mostly at subspecies level and it can be concluded that in terms of species structure, Perinereis polychaetes of Deylam, Bushehr, Dayyer and Bandar Abbas, showed low genetic divergence.

In this resaerch for introduction of late Cretaceous calcareous nannofossils in Middle Tethys Ocean, Azizabad stratigraphic section of the the Farokhi Formation in Central Iran has been selected. Thickness of formation in this section is 233 meters and consists of marl and marly limestone. In this research 42 species belong to 25 genera of nannofossils with good preservation were identified. Based on the index nannofossilspecies and nannofossil assemblages, CC21-CC26 for Farokhi Formation determined. Deterrmined biozones indicate early late Campanian – late late Maastrichtian age for Farokhi Formation in Azizabad section.