Mesopotamian Journal of Marine Science

In the present research, a numerical model was developed using the software package Mike 11 to study the water quality of the Shatt Al-Arab river (TDS, DO, TSS). Three stations were selected at the upstream of River (Qurnah) in the middle (Ma,aqal) and downstream (FAO). A value of (50 m3/sec) discharge was used in chain age (0.0 m) and time series file for heights of tides in chain age (240932.0 m) which was the implementation of the programme for one year after calibration and verification between field measurements and the programme outputs, they show that there is a good compatibility. On using the value (250 m3/sec) to explore the impact of high discharge of river on water quality, this study shows that the discharge of the river plays the role of reverse with increase and decrease in these characteristics as well as the location of measuring stations on the estuary, in which all the values of variables are increased has an obvious effect. If the measurement station became closer to estuary that’s lead to increase in the value for variables, because of the tidal river were the values for variables in some stations in flood case larger than of ebb case. The programme represents a first step towards preparing a programme containing more water quality variables. After the success of the programme, made it possible to calculate any of the three variables after knowing the value of the discharge of the river and enter the time series of tidal heights.

The current study is a comparative analysis of the Gill Respiratory Surface Area (GRSA) and some features of the red muscle fibers including the proportions and diameters of the red muscle fibers in three body regions in two teleosts species; torpedo scad, Megalspis cordyla (L.) which belongs to the carangid and the red belly tilapia, Cotodon zillii (Gervaias, 1848) which belongs to cichlids. Fifty fishes (25 fishes for each species) were used in the current investigation. They range in length from 100 to 300 mm and their weight ranged between 66 and 305 gm. The results show that the M. cordyla have GRSA ranged between 78 and 100 mm2/gm whereas it ranged between 56 and 146 mm²/gm in C. zillii. The fish weight was the influential factor on the values of the relative GRSA (mm²/gm) while the total length of gill filaments was the influential factor on the values of the total GRSA (mm²) of the studied fishes which showed significant differences (p<0.05) between the studied species. The difference in the proportions of the red muscle fibers among the three body regions of both species showed a significant difference (P<0.05) between the total length of the fish and the proportions of the red muscle fibers which ranged between 8.16 and 12.80 % in M. cordyla whereas it was between 5.42 and 9.24 % in C. zillii. Also the results presented an increase in the proportions of the red muscle fibers towards the posterior region (R3) which were 8.80-12.80 % in M. cordyla while they were 6.24-9.24 % in C. zillii. The results revealed that the approximate diameters of the red muscle fibers varied between 13.70 and 47.85 µm in M. cordyla while they ranged between 17.10 and 44.50 µm in C .zillii but were not statistically significant differences (P>0.05) between the two species.

For a long time the Iraqi regional waters of north-west Arabian Gulf were classified as free of seagrasses due to the absence of the information concerning these important angiosperms. During the survey carried out by scientist of the Marine Science Center and German divers in 2013-2014 to study the Coral reefs distribution and occurrence in this area, the divers with the help of underwater camera caught photos indicates the existence of seagrass meadows in different places of the north-west Arabian Gulf, so the efforts were made to examine this issue and a work were carried out in April 2017 to study the existence, species composition, occurrences and distribution of seagrass species in the Iraqi marine waters of the north-west Arabian Gulf for the first time. Six sites were chosen distributed along the north-west of Arabian Gulf where the depth was ranging from 0.5 to 15.0 m. Six meadows of seagrass were identified, classified, mapped and seagrass diversity and abundance were investigated. Four species of seagrass namely Halophila stipulacea (Forsskal) Ascherson, Halophila ovalis (R. Brown) Hooker f., Halophila decipiens Ostenfeld and Halodule uninervis (Forsskal) were recorded for the first time in Iraq. Halophila decipiens Ostenfeld was recorded as a new to the whole area of the Arabian Gulf and the Iraqi marine waters and found at a depth of 12-15 m. Halodule uninervis was found to be the most dominant species at all the studied sites followed by Halophila stipulacea. The total seagrass area estimated at all the stations was about 678 hectare fluctuated at different stations. Higher Seagrass total coverage area (240 ha) was found at shallower waters (0.5-3.0 m) compared with 60 ha at deeper waters (12-15 m). The exposed locations showed low seagrass coverage of 35 % comparing with sheltered sites (65 %). The relationship between depth and total coverage of seagrass was significant, while it was not significant with sites. Highest richness value was found in the Alkheran area (Khor Al-Zubair) at a depth of 0.5 m. The relative evenness of the seagrasses species, with different depths showed that the depth 0-3 m has the highest value. The distribution of seagrasses in Khor Al-Zubair and Khor Abdullah down to the open area of Khor Al-Omaya was mapped by using the GIS and Arc Map version 10.5 applications.

Elemental mercury is associated with industrial wastes discharged through the main effluent pipe of the chlorine-Alkali plant at Abo-Kamash area west of Libya. The minimal mercury value of 0.1 ppm dry weight is assumed to be the background level for the uncontaminated sediments in the area. Mercury level ranged from 0.193 to 0.310 ppm in the sediments from the polluted area beyond the plant. The concentration of total mercury in fish muscle ranged from 0.176 and 3.586 μg/g wet wt. The Chlorine-Alkali plant is obviously the major source of mercury pollution.

The improvement process by adding polymers and cement has been carried out to sub-base material used in the compaction processes, in order to observe their effects on the geotechnical properties of the sub-base such as compaction, unconfined compressive strength, shear strength, California bearing ratio and absorption ratio. It has been observed that there is a significant improvement in the geotechnical properties of the soil as the value of the maximum dry density increased from 2.144 to 2.220 g/cm3, while the value of the optimum moisture contents decreased from 6.3 to 5.2% with a percentage of 5 % of the first polymer (Polyvinyl Acetate & Polyol). It is also revealed that there is an increase in the value of the unconfined compressive strength after adding 5% of the first polymer and 5% cement to the sub-base sample, and then soaked in water for different periods of time, the result was 11550 kPa with a
soaking period of 28 days. Also, the angle of the internal friction values increased in testing the direct shear strength from 35◦ to 45◦ by adding 5% of the first polymer, and cohesion occurrence among the particles of the material under the action of the polymer as a adhesive material, the value reached 200kN/m2. The California bearing ratio increased from 49% to 64% by adding 5% of the first polymer, while the absorption ratio decreased considerably at the same ratio and material from 9.8% to 4.1%.