Journal of the Persian Gulf (Marine Science)
Volume:4 Issue: 11, Spring 2013

Microbial biofilm layer could grow on bed surfaces and affect the normal sediment properties following polluting of water resources. However, limited research is done to measure the effects of biofilm in the long run. The objective of this study was to investigate the erosion-deposition phenomena considering factors such as sediment concentration, flow velocity and bed surface along the flume length. So, a three- part flume was designed; a narrow part and a wide part to show erosion and deposition, respectively and a transition part to connect these two parts. Experiments for various time periods of biofilm growth were managed to measure the required parameters inside the flume. Finally, the results for various positions were analyzed. For longer time series of biofilm growth, less values of erosion were measured.

In this study, the concrete-steel bond strength of concrete filled cylindrical steel tubes has been experimentally investigated. 22 short, high strength and normal concrete filled circular steel tubes were tested. Push-out test was carried out as the common method to evaluate the bond carrying capacity. Four different concrete mixes were used in preparing the specimens. The steel tubes were welded type with the nominal inside diameters of 3, 4, 6 and 8 inches. According to the test results bond strength increases with reduction of the w/c ratio of concrete mixes. The high strength to normal concrete bond strength ratio increases with the diameter of steel tubes. The bond strength decreases for higher diameters in both normal and high strength concrete specimens.

The status of metal concentrations including Pb, Cd, Cu, Ni, Zn and Fe in six species of Padina were determined in polluted (Nayband Bay) and unpolluted (Bostaneh port) areas on the Coast of the Persian Gulf. The mean concentrations of metals in the sediment of two locations were: Pb (12.64), Cd (3.59), Cu (21.74), Ni (17.00), Zn (32.00) and Fe (677.53) µg g-1 dry weight, respectively. In the present research, mean metal content in sediments and algae decreased in the following order: Fe > Zn > Pb > Ni > Cu > Cd. The highest Metal Pollution Index (MPI) value was recorded in Padina borgessenii was 25.02 at Nayband Bay. The positive correlations between metal contents in the sediment and almost in all species indicated that these algal species could absorb metals from sediments and play role as biomonitoringσ gents.

Through a series of research cruises conducted by the R/V Ferdows-1 to assess Myctophid resources, using a SIMRAD EK500 scientific echosounder carried out the Target Strength measurement of Benthosema pterotum in the Oman Sea. The principal method was based on a direct in-situ split-beam measurement technique, which is implemented in the EK500 system. For real-time observations, the target strengths corresponding to resolved single-fish echoes were collected in a histogram. Associated statistics included the number of observations and the depth range. The processing of the TS-telegram data took place in the Procomm software (version 1.16), which converted into a tabular form and based on one-coefficient regression analysis to express the TS. The second method that also yielded information on target strength of myctophid through estimation of the mean, effective backscattering cross-section of the target fish related to the method of integrating the fish layer in the front of the trawl mouth during towing and related it to the total catch observed.The final results showed the approximate equation: TS=20logL-71.7 (dB), where L is the total length of the fish in cm. The collected data can be applied to improve later biomass-backscattering cross section analysis.

This paper presents the results of studies performed to rehabilitate an existing seawall in Fujairah to withstand cyclone Gonu condition. The exiting section has not been designed for the cyclone Gonu condition. A desktop study was implemented to assess the functionality of the existing section by applying the methods recommended in the applicable standards and guidelines. This assessment showed that the existing seawall would be severely damaged and excessively overtopped during the cyclone wave condition. Some measures were implemented for the typical section of the seawall. The proposed improved sections were physical model tested and the results compared with the empirical methods.

The objective of this study was determining the heavy metal contents in sediment along the coastlines of Hormuzgan province. Sediment constitutes are important part of aquatic ecosystems. They provide habitat for benthic organisms and could be a significant sink as well as a potential source of contaminants. Three sources of heavy metals pollution in this area are industry, natural mineralogy of soil and oil. The levels of heavy metals (Pb, Cd, Cu, Ni) have been investigated over a 4 season period at 9 sites. We collected sediment samples from a depth of 0-10 cm. Heavy metals assessed by the atomic absorption spectrophotometer. The results showed Pb, Cd, Cu, Ni concentrations in the sediment ranging from 3.00 to 28.00 g/g, 2.96 to 10.11 g/g, 2.60 to 11.27 g/g and 8.03 to 105.30 g/g, respectively. Seasonal study showed that pollution levels in sediments at spring and summer were more than autumn and winter. The heavy metal concentrations lead to the following ranking: Pb> Ni> Cu> Cd. Based on Pollution Index (MPI) values, our result indicated that station 9 was polluted area and station 2 was unpolluted area.

The effect of Kutum (Rutilus firisi kutum) stock enhancement for homing behavior and imprinting with morpholine were studied during 2004 to 2008. This species is a migratory anadromous fish, spawning in rivers in March–April. It has a group synchronous and single spawning behavior. Total of 15, 930 Tagged (ABC Tags) specimens of Kutum fingerlings were released into the Khoshkroud river estuary (South part of the Caspian Sea). Kutums were treated with synthetic amine based odorant morpholine (C4H9NO) with different concentrations (5x10-2. 5x10-5 and 5x10-7 mg/lit) to enhance imprinting of natural river odors and promote homing behavior. To find the best time of exposing at various developmental stages, Kutums were treated with 5x10-5mg/lit morpholine in yolk sack, active larvae, 2-3 g. fingerlings and 4-5 g. fingerling stages. Results revealed that significant differences (P<0. 001) existed between kutum homing rate exposed to 5x10-5 mg/lit (0. 5 %) with other treatments i. e. 5x10-7، (0. 16%) and 5x10-2 (0. 1%) as well as with control (0. 02 %), during the experimental period. Total Return rate was 0. 32%. Results showed significant differences (P<0. 001) between kutum return (homing) rate in active fry stage (1 %) compared to other stages, i. e., yolk sac fry (0. 23%), 2-3- g fingerling (0. 23%), 4-5 g. fingerling (0. 26%) and control (0. 13%) during the tree years of experimental period. There were significant differences in sex ratio [M (1. 42): F (1)] in recaptured kutums in khoshkrud river (x2=6. 4 α= 0. 05 df= 1). Average recapturing rate was greater (6. 7 %) than the average recapturing rate for the 5 year period of 2000 to 2004 (5%). As such, it is suggested that revealed that morpholine could be used for return rate enhancing of kutum. Results reviled the role of morpholine as an pheromone like substance for enhancing migratory behavior of Kutum (Rutilus firisi kutum) fish.