Recent Submissions

  • Stock Assessment and Management of Dilplodus: Speciee in Abu Qir Bay, Alexadria, Egypt

    Adam, Adel Mohamed Saleh (2010)
    The present study deals with the fisheries of two Sparid fish species in Abu Qir Bay. Family Sparidae represents about 17 % of the landed catch from the Bay. Among the family; genus Diplodus is generally caught by trammel nets, beach and purse seines but mostly by longlines. Two species of this genus were considered here for study. They are namely D. sargus and D. vulgaris where they represent by about 4.2% of the landed catch during the year 2008 in the Bay (GAFRD, 2008). The length weight relationship of both species under study showed a value of exponent “b” of very slight negative allometry. Analysis of the catch length structure of the two species revealed that the catch of D. sargus is composed of 21 length groups, the least length was 7.5 cm and the biggest was 27.5 cm with mean length 16.16 cm, while the catch of D. vulgaris is composed of 19 length groups starting from 8.5 cm to 26.5 cm with mean length 16.23 cm. The most abundant length group was 17.5 cm for the two species and both have nearly the same mean length. Study of the sex ratio showed that the females dominate the population in both species. The study of condition factor “K” showed that the value of “K” decreases as the fish increases in length and also varies with season. Length scale relationship was found to be linear. Back calculations of the total lengths by the end of each year of life, showed that the rate of growth of D. sargus was higher than D. vulgaris in both length and weight. Thus D. sargus was 11.42 cm total length at age I and reached 25.98 cm total length at the sixth year of age. For D. vulgaris it was 10.34 cm total length ate age I and reached 25.52 cm total length at the sixth year of age.Growth in weight studies show that for D. sargus, the fish was 26.77 gm total weight at the end of the first year of life, while it was 300.47 gm at the sixth year age of life. For D. vulgaris, it reached 18.30 gm total weight at one year old, while it was 267.24 gm by the end of the sixth year age of life. No difference in rate of growth between males and females (Linear and Ponderal). This is true for both species. Besides, the values of Von Bertalanffy parameters were estimated and compared for the two species. D. sargus comprises seven age groups from age group 0 to age group VI as well as D. vulgaris. The most abundant age groups are I and II for D. sargus, while in D. vulgaris it was age group II. The values of total, natural and fishing mortalities for both species were estimated. They were slightly higher in D. sargus than in D. vulgaris. The same was true for the values of growth performance in length and weight (ФL and Фw). The Survival rate was slightly lower in D. sargus (0.34), than in D. vulgaris (0.35). The values of exploitation rates were also higher in D. sargus (0.445) than in D. vulgaris (0.428). The length at first capture was nearly the same for both species (12.51 cm and 12.52 cm “Total length”) for D. sargus and D. vulgaris respectively. The corresponding ages were 1.208 year for D. sargus and 1.42 year for D. vulgaris. Fishes belonging to D. sargus reach 10.43 cm TL when they recruit to the population, while D. vulgaris reach 10.62 cm TL at recruitment. These correspond to 0.81 years in D. sargus and 1.05 years in D. vulgaris. The yield per recruit obtained by the analytical model of Beverton and Holt, 1957 was found to be 27.76 gm for D. sargus and 25.99 gm for D.vulgaris. The biomass per recruit for D. sargus is 57.16 gm, while it is 57.90 gm for D. vulgaris. The estimated yield per recruit and biomass per recruit at F0.1 (Target reference point) were 27.7617 gm and 57.16 gm for D. sargus and were 26.5552 gm and 54.87 gm for D. vulgaris respectively. These values were corresponding to fishing mortality values of 0.486 year-1for D. sargus and 0.484 year-1for D. vulgaris. The maximum yield per recruit (Y/Rmax) for D. sargus was 31.1233 gm which correspond to a value of Fmax= 1.239, while for D. vulgaris it was 29.7867 gm corresponding to Fmax =1.245. At Fmax the percentage of biomass per recruit value to virgin biomass was 16.26 % for D. sargus and 16.09 % for D. vulgaris. The effects of fishing mortality together with age at first capture on the values of yield per recruit were estimated for the two species under study. It showed an increase in age at first capture (tc) has little effect on Y/R in both species under constant value of fishing mortality. Cohort analysis (VPA, age based) represent the estimated values of the population numbers, Survivors, Natural and fishing mortalities for each year of life of D. sargus and D. vulgaris in Abu Qir Bay. It is noticed that, the populations of the two species under study decreased gradually with age, this is due to the exposure to the sequence of natural mortality (which decrease with age too) and fishing mortality (which appeared in different trends in the two species). It showed that, the catch is based mostly on fish of age groups I, II and III in both species under study. On the other hand, the effect of F on Y/R at different values of natural mortality (M) showed that the Y/Rmax value corresponding to higher values of fishing mortality at higher values of natural mortality, for both species. From another point of view, it was found that the value of Y/R decreases as the value of natural mortality “M” increases. This is true in both species. This shows the effect of water pollution on fish production. This study concluded that, the fisheries status of D. sargus and D. vulgaris in Abu Qir Bay reached the target reference point (F0.1) but did not reach the overexploited phase, because they did not reach the limit reference point (Fmax) for the two species under study.
  • Seasonality of Surface Chlorophyll in the Red Sea

    Ahmed, Mohammed Elamin Bashir Hassan (Universitas Bergensis, 2012)
    Although the understanding of the oceanography of the Red Sea has been developed over the last few decades, but we still have a little knowledge about the influences of the physical factors on the phytoplankton activity. The purpose of the present study was initially to quantify and investigate the seasonal variation of surface chlorophyll concentration (CHL-a) at three zones in the Red Sea (north, middle and south). The second goal is to identify the controlling factors which seem to have an effect on the phytoplankton bloom during the same period of the study. To reach our goals, we use remote sensing data (surface chlorophyll, sea surface temperature and photosynthetically available radiation), oceanographic data (wind speed), and modeling data (mixed layer depth) received during the period 1998–2009. The data are analyzed using BEAM/VISAT software and statistical methods to reveal principle features of the phytoplankton bloom. The results indicate different mechanisms of the phytoplankton bloom and different importance of controlling factors at the three zones of the Red Sea.
  • Prevalence of Marine Zooplankton around Port Sudan

    Ginawi, Amjed Ginawi Ahmed (University of Khartoum, 2010)
    Marine zooplankton and some physical parameters (water temperature and transparency) and chemical parameters (salinity, pH and phosphate, nitrate, nitrite and oxygen) were studied from November 2009 to October 2010, at six stations around Port Sudan. The stations were: Tires Factory (station 1), Fish market (Station 2), Open Sea (Station 3), the harbour entrance (Station 4), the Faculty of Marine Sciences and Fisheries (Station 5) and Sea Land (Station 6). Marine zooplankton was sampled, preserved, stained and identified according to the standard methods. The physical and chemical parameters were determined following standard methods. Fifteen groups of zooplankton (calanoida copepods, cyclopoida copepods, branchyuran zoea, fish eggs, cladocerans, oikopleura, shrimp larvae, sagitta, cumaceans, tintinids, gastropod larvae, radiolarians, napulii, medusae, and polychaete larvae) were recorded from the different stations at different frequencies. The highest number of zooplankton was recorded in May (13430 ind. /m3). Calanoida copepods, cyclopoida copepods were the dominant groups and cladocerans were the least recorded. The highest number recorded in a station was (18998 ind/m3) in station 1 and the least was (5519 ind/m3) at station 6. Multiple correlation analysis was used to quantify the relationship between the total number of zooplankton and the physical and chemical parameters at each station. The correlation was significantly high (p<0.05) in station 4 and low in station 5. A positive relationship was found between dissolved oxygen concentration, transparency and nitrate concentration with the total number of zooplankton. A significant correlation (p<0.05) was found between high salinity and low total number of zooplankton. The study derived a mathematical model correlating total zooplankton with the physical and chemical parameters studied. This model perhaps may be the first of its kind in the Red Sea. The study recommends deriving similar models from other parts of the Sudanese coast and the region, and verifies the feasibility of its application with focus on the physical and chemical parameters with highest impact on marine zooplankton. This will reduce the effort and resources expended in these studies.
  • Geological and structural investigation based on regional gravity and vertical electrical sounding data of the East Nile Rift Basin – Sudan

    The analysis of geology and structure of the study area (East Nile - North Khartoum) is attempted by utilizing regional gravity and vertical electrical sounding (VES) data to investigate the source of the high gravity encountered over the basin features in this area as well as to reveal the structures, sedimentary sequences and groundwater condition in the area. The regional gravity measurements are achieved along two profiles in the area using Scintrex CG-3 gravimeter. All corrections common in gravity method are applied to the field data to produce Bouguer anomalies. The Bouguer anomalies are combined together with those produced by Sun Oil Company in 1984 and the residual anomaly separation is made using the least-squares method. The residual anomalies are interpreted using a 2D gravmodeller program (computer program) with the aid of geologic information in the area to produce geologic sections of subsurface of the area. As a result, the most convenient explanation of the high anomalies is the presence of granulites with density of 3.1 g/cm3. They are suggested to be uplifted during the period of the Pan-African movement to a depth of less than 3000 m below gneissic rocks with a density of 2.7 g/cm3 beneath the Nubian Sandstone with a density of 2.3 g/cm3, and its tip is thrusted to the surface at Sabaloka. Additional results are obtained from the interpretation of the gravity data. Several sedimentary basins, which were previously discovered, are delineated here again. The most important one is Atbara Basin in which the total thickness of sediments is about 3000 m. A depth map of the Basement surface of the study area is prepared. A dextral strike slip fault parallel to that appears at Sabaloka area is discovered in the area extending beyond River Atbara. The vertical electrical sounding (VES) measurements are conducted in the area using SAS 1000 meter to reveal the sedimentary sequence and further to investigate the groundwater condition in the area. The measurements are concentrated at Musawarat, El Awatib, Es Salama and Wad Musa areas. The present resistivity data are combined together with the old available data for more details. The VES data are interpreted using IPI2win software. A number of 8 geoelectric/geologic cross sections are prepared. As a result, the subsurface of the area consists of six geologic layers: - The first layer is the surface layer consists of undifferentiated sedimentary facies (gravels, sands, clayey sands, sandy clays and clay). - The second layer consists sandy-clay, clayey sands and sands. - The third layer is saturated sandstones. - The fourth layer is silicified sandstones/claystones (aquifuge). - The fifth layer is saturated sandstones. - The sixth layer is Basement Complex. The third layer and the fifth one are upper free aquifer and lower confined aquifer, respectively. The lower aquifer is thicker than the upper one. So, its water is the most abundant and convenient for drinking and irrigation purposes. Five subsurface geologic maps are prepared. Two of them are depth maps of the top surface of the upper and lower aquifers. The other two are thickness map of the upper and lower aquifers. The last one is a depth map of the Basement surface.
  • The Inorganic carbon cycle in the Red Sea.

    Ali, Elsheikh Bashir (University of Bergen, Geophysical Institute, 2008)
    The inorganic carbon cycle in the Red Sea has been examined based on various datasets from six different years during the period 1977 and 2007. The study has been performed parameter wise, and the processes biological production/remineralization (soft tissue and hard parts), calcium carbonate sedimentation, air-sea gas exchange, and evaporation/precipitation have been considered. The surface water was relatively warm in the central part of the Red Sea due to wind convergence, and colder towards the south and north due to influence of relative cold Gulf of Aden water and net evaporation, respectively. The surface salinity increased all the way from the south towards the north, due to evaporation, and this explained the major part of the northwards increasing concentration in both surface AT and DIC. The surface AT was, in addition slightly influenced by biological production. Air-sea CO2 exchange was believed to influence the surface DIC, however, this effect seemed to be hidden in the random error of the observed data. For the deep water, the AT concentration was mainly influenced by calcium carbonate sedimentation, while remineralization/respiration could explain the major part of the DIC variations observed. fCO2 was positively correlated to the sea surface temperature. During the period 1977 - 2007, the fCO2 of the water increased at a similar rate as the atmospheric fCO2, however, while the atmospheric CO2 increase had obvious reasons, the oceanic increase most likely was a result of an increase in surface temperature. Air-sea CO2 flux was calculated, and the Red Sea was in general a small source for atmospheric carbon for all years except 1991 and 1992, when the southern parts of the ocean appeared as a large source and the northern part had turned into a small sink for atmospheric carbon. This particular situation in the north was connected to strong NNW wind and subsequent upwelling in the north during these two years.
  • Wave and wind conditions in the Red Sea: A numerical study using a third generation wave model

    Saad, Ahmed Mohamed Elfatih (2010)
    In order to understand how waves behave and how other parameters can interact between ocean and atmosphere we can use a numerical model. For the Red Sea basin wave measurements are absent and due to that a WAM wave model is used to study the wave climate. The aim of this thesis is to run a wave model for the Red Sea area to begin a local forecast service and then estimate climatology of wave height, needed in almost all coastal engineering studies. As well as to give engineers a description of ocean surface waves and forces, this knowledge about Red Sea wave conditions can help the local shermen that use small vessels. The third generation wave model WAM is used to hindcast the wave condition in the Red Sea for the year 2007. The WAM model is forced using wind data obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF).
  • دراسة مواد البناء البديلة فى منطقة البحر الأحمر: المواد البوزولانية

    Edris, Abass Edris Alsaid (2012)
    Pozzolana is a materials that content Reactive Silica with Alumina which defines as Siliceous materials, also include ferroginous materials. In generally, this study aimed to estimate Alternative building materials ( pozzolanic materials ) and create new cementic materials such as Lime-Pozzolana Cement and Ordinary Portland-Pozzolana Cement . The results shows that there is no good and sufficient pozzolanic materials as Obsidian , Scoria, Diatomaceous Earth and Volcanic Ash , but some types of burnt clays and Rhyolite in addition to bricks Reject and miskeet Ash was shown . This study is subjected in Arbaat Delta clay , salloum Delta clay , Rhyolite Rocks , bricks Reject and miskeet Ask as Natural and artificial pozzolanic materials. The identification of above mentioned materials was carried out by using several methods includes Geological survey , Chemical Analysis and X-Rays . and physical properties tests for prepared cementic materials includes setting time , Expansion , Fineness and Compressive Strength . the aim of pozzolanic activily and its Reaction with lime and Ordinary Portland Cement . The physical properties tests of the prepared cementic material such as setting time , expansion ,Fineness , chemical analysis and X-Ray shows that Arbaat Delta clay , salloum Delta clay and bricks Reject are suitable from prepared mixtures Lime- Pozzolana cement (L .P.C) and Ordinary Portland- Pozzolana cement (O .P .P .C), as well as Comperessive Strength results during 28 days which as follows : Arabaat delta clay is 34.4 kN/mm², clay of salloum delta clay is 32.2 kN/mm², and bricks reject is 31.5 kN/mm² as averages of two samples for a mixture lime–pozzolan. As for the Ordinary Portland- Pozzolan cement, the results of the tests the Compressive Strength as follows: the Arbaat Delta clay is 35.6 kn/mm² , 34.2 kN/mm² for Saloum Delta, bricks reject is 32.1 kN/mm².as average of two samples . these result are suitble for pozzolanic materials but less in pozzolanic suitability than those of Obsidian , Scoria , Diatomaceous Earth and Volcanic Ash . Rhyolite rocks and the ash of miskeet trees contain crystalline silica, as was shown in X-Ray results , for this reason they have not a good results in Compressive Strength their results were very weak, where 19.7 kN/mm² and 3.1 kN/mm² respectively as the average of two samples for a mixture lime – Pozzolana cement and 22.1 2kN/mm² and 3.4 kN/ mm² for average of two samples of Ordinary Portland- Pozzolana cement .
  • Study and Evaluation Of Balila Oil Field Vis-breaking plant

    Mohammed, Babiker Krama Abdalla; Basheir ,Emam Mohammed; Red Sea University (2009)
    In this study the Vis-breaking plant of Balila crude oil which is owned by Petro Energy Company was studied and the benefit in cost of this plant was calculated. The improvement in crude oil quality was tested. Besides investigating how Vis-breaking plant contributes in energy saving hence minimize its consumption. The flow characteristics of crude in pipeline were studied experimentally before and after Vis-breaking plant and described mathematically. Rheological models were developed to relate the shear stress to shear rate. These models were used to describe the effects of oil viscosity on the pressure required for pumping the oil through pipelines. The result of present study shows that the rheological characteristics of crude oil were improved from bulk Non- Newtonian to the Newtonian fluid at testing temperature, although the vis-breaking plant used as upstream unit, it has been never applied before.
  • Phytoplankton biomass and production in the coastal water off Goa, West Coast , India.

    Saad, Osama S.; Goa University (2010)
    The coastal water off Goa is a characteristically interesting marine environment due to influence of the monsoon and upwelling. Studies on the primary productivity and related areas revealed the following results. - Water column is stratified during October and remained well mixed during November. - Hypoxic condition prevailed at the bottom during October but not in November. - Nutrients (especially Nitrate) was low during October (surface) but increased during November. High nutrients remain in bottom largely due to intense stratification during October. - Phytoplankton biomass (Chl a) average was high during October of 2.34 mgm^3 and in November it was as low as 0.62 mgm-3. - Chl a at 30m depth was as high as 1.03 mg m-3 and that of November it was 0.43 mgm^-3. - Primary Production during October (Surface) was 612.62 mgCm-3 day-1 and that in column was 14.96 gCm^-2day^-1. During November surface productivity was 219 mgCm-3day-1 and that of column was 4.13 gCm-2day-1. - In fractionation study picoplankton contributed 35.75% of total Chl a.However, in Primary production picoplankton contributed 92.54% of the total production at the surface during October. Total 46 species of phytoplankton were observed in the study area and major being diatoms (i.e. 33 species) and 13 species of dinoflagellates. Chemotaxonomic studies also indicated diatoms domination in whole sample as well as in fractions of <10 microns dominated by picoplankton.Most importantly the coastal water off Goa remained well stratified during October month and well mixed during November month. Due to this, Chl a during October is high compared to that in November. This is in agreement with nutrient data during October and November months. The sample taken from the 30m depth demonstrated negligible productivity although Chl a is measurably high. The carbon production at the surface water was much more during October (612.62 mgCm-3 day-1) compared to November (219.1 mgCm^-3day^-1). The factors responsible for lower production are water column stability and availability of light in the coastal water off Goa.
  • Sudanese Coastal Water Composition and Some Environmental Aspects

    Leiv, K. Sydnes; Ingunn, Skjelvan; Ali, Aasim (2012)
    Red Sea water samples were collected from four stations in the Sudanese coast at depth of 10 m during July 2011 and analyzed for major ions and trace metals in order to determine their insitu concentration, their distribution patterns, and level of heavy metals contamination in the Sudanese coastal water. The data of the analysis was used in the preparation of the Red Sea artificial water which was used to study how salinity affects the photooxidation of 1,8-dimethylnaphthalene (1,8-DMN) and the water-soluble fraction (WSF) from Norwegian crude oil. The results show a small range of spatial variation for Na+, Mg2+, Ca2+, Cl−, K+, and SO2−4 . Also, the concentration of Na+, Mg2+, Ca2+, Cl−, and SO2−4 in the Sudanese coastal water is high compared to all other water basins and average seawater. The reason of this is the high evaporation and low precipitation in Red Sea.The concentrations of the major ions Na+, Mg2+, Ca2+, and K+ at the coastal stations are some what lower than at the other stations. This might be due to the adsorption of these ions by the suspended particles. Cu, Ti, As, Co, Cr, La, and Eu did not give any instrumental response, which means either that their concentrations in the Sudanese coastal water are below the detection limit of the instrument or the elements do not occur in the Sudanese coastal water. Thus, in order to detect their concentrations, preconcentration should be done or another more sensitive method should be used. The results show a low concentration of Sr (7.6 mg/L) compared to the concentration of Sr in average seawater (8 mg/L) and this decrease in Sr concentration may be due to the presence of Acantharians. Also, concentration of B is low compared to the concentration of B in average seawater and the reason for this is that boron is partly present in seawater as the neutral compound B(OH)3 which can be distilled from surface water in the tropics during evaporation process. Unfiltered seawater samples were collected from five stations in the Sudanese coastal water. The extractable organic matter (EOM) ranged from 1.3 to 10 mg/L with an average of 4.46 mg/L. The highest concentration of EOM was observed at the closest station to the coast. The dissolved/dispersed petroleum hydrocarbons (DDPHs) concentration equivalent to Sudanese heavy crude oil ranged between 15.84 and 95.92 μg/L with an average of 40.95 μg/L. The level of DDPHs at Sudanese coastal water does not affect the planktonic ecosystem. Photooxidation experiments of 1,8-dimethylnaphthalene (1,8-DMN) under artificial sunlight and natural sunlight in deionized water, Red Sea natural water, and Red Sea artificial water, revealed that the oxidation of 1,8-DMN in a dark environment is dependent on temperature. The results show that salinity has no effect on the photooxidation of 1,8-DMN. But it might affect the kinetic of the reaction. The results show that the nature of the oil affects the photooxidation of 1,8-DMN. The WSF from Norwegian crude oil consists of low molecular weight aromatic hydrocarbons. These compounds had disappeared after two days of irradiation. This reinforce photodegradation as an effective weathering process for the transformation of dissolved crude oil fraction, particularly in high solar radiation environments such as the Red Sea.
  • Ocean acidification in the Arabian Sea and the Red Sea

    Omer, Waleed (2010)
    The CO2 increase in the ocean due to the uptake of anthropogenic CO2 is of major concern, due to potential changes in future ocean CO2 uptake that might be driven in a direction of relative less CO2 uptake in the future then today and the companying lowering of ocean pH. In this study we investigated the variability of CO2 system parameters, focusing particularly on the pH and how it changes with changes in other parameters like: temperature (T), salinity (S), total dissolved inorganic carbon (CT ), and total alkalinity (AT ). For Arabian Sea the data from the United States Joint Global Ocean Flux Study (US{JGOFS) in 1995 were used. For the Red Sea data from the Geochemical Ocean Section Study (GEOSECS) in 1977 and the Mer Rouge (MEROU) cruises in June and October 1982 were used. One of the major outcome of this research is: The seasonal and spatial variations in pH and therefore also for calcium carbonate saturation ( Ar for Aragonite and Ca for Calcite) is controlled by biological and physical processes that in turn is driven by the in uence of monsoonal seasons. In winter season the surface average pH, Ar, and Ca in the Arabian Sea were 8.07 0.01, 3.9 0.1 and 5.9 0.2, respectively. A relatively high biological production, due to the winter cooling and mixing caused by the northeast monsoonal winds increase the pH. During summer season Southwestern monsoonal winds caused upwelling along the coast of Oman, resulting in extremely low pH ( 7.9) values causing lower saturation for aragonite (Ar 2.36) and for calcite (Ca 3.62). Because of the strong change in pH, this area might serve as a natural laboratory for studies of ocean acidi fication.For comparison, in the Red Sea, the surface average pH was 8.1 0.02 during winter with higher values in the north due to lower temperatures and high AT and CT . The Ar and Ca were around 4.12 0.02 and 6.2 0.15, respectively, with highest values in the central part of the basin caused by higher temperatures. Summer surface pH was 8.07 0.03, with higher values in the north and the south due to the temperature. In the central of the Red Sea, pH was low due to the convergence (high temperature). The Ar and Ca were averaged to 4.6 0.3 and 6.95 0.35,respectively, with higher values in the south and north. This is attributed to the high biological productivity in the south and the high temperature in the center of the Red Sea. The vertical distributions of Ar, and Ca showed that the Arabian Sea is under-saturated with respect of aragonite below 600 meters and calcite below 3500 m, whereas the Red Sea is supersaturated throughout the water column. In both seas pH was higher in the surface layers due to the consumption of CO2 by photosynthesis, but decreased rapidly in subsurface waters due to the release of the CO2 by respiration processes. Between about 100 and 1500 m in the Arabian Sea pH is nearly constant because decreasing temperatures and decreased oxidation of the organic matter. The temperature e ect on pH is about 0.015 units per 1 C and anticorrelated both in the Arabian Sea and Red Sea. Thus, the 0.5 C warming reported for the Arabian Sea between 1904 and 1994 (Kumar et al., 2009a) theoretically results in a pH reduction of about 0.007. The temporal coverage of the available data is unfortunately too short to verify this assumption.
  • Seasonal and Interannual Variations of Surface Nutrients and Hydrography in the Norwegian Sea

    Ibrahim, Ahmed (2012)
    Seasonal and interannual variations of surface nutrients and hydrography data obtained in period (1997-2010) by the Institute of Marine Research over three transects: Fugl ya-Bj rn ya, Gims y and Svin y located in the Norwegian Sea have been studied. The results over the Fugl ya-Bj rn ya transect show good signature of the seasonal cycle of nitrate and temperature reacting both bloom and post-bloom periods. The Gims y transect shows a weak seasonal cycle of nitrate and temperature in the outer part because there is no enough data during the bloom and post-bloom period. But the middle and inner part show good seasonal cycle of nitrate and temperature during the two periods. Finally, the Svin y transect shows good seasonal cycle of nitrate and temperature during the bloom and post-bloom. The results over the three transects do not reveal much information on the interannual variations of temperature, salinity and nitrate. This due to the changes in the timing of the cruise. Also the availability of information is short over three transects.
  • Study of Inter-annual Variability of Chlorophyll in the Red Sea

    Elawad,Abubakr (2012)
    This thesis studies and estimates interannual chlorophyll-a concentration in the Red Sea water using SeaWIFS, MERIS and MOIDS data. We use the data of Chlorophyll-a (CHL-a) for the period from 1998 to 2009 as well as other physical parameters such as, sea surface temperature (SST), photosynthetic available radiation (PAR), wind and mixed layer depth (MLD) to study what control the inter-annual variations of phytoplankton blooms in the Red Sea. The area under study is divided into three zones which cover the north, the middle and the south zones of the Red Sea. When considering the data seasonally, the CHL-a shows that blooms alwaysoccur in the Red Sea during winter. For each zone, the start and the end of the blooms are different from other zones. During all three zones, the CHL-a is increasing during winter and decreasing during the summer for example, the average high value of CHL-a in the north zone during the blooms is (0.26 mg/m3 ) and the minimum value is (0.14 mg/m3 ). only in the south the blooms started in the summer in September and the highest value of CHL-a during the blooms recored is the south too (0.9 mg/m3 ). The study shows that the physical parameters have effect in the blooms sizes In each zone, significant correlations between CHL-a and some of the physical parameters is found indicating how physical processes may control the phytoplankton blooms in the study area. such as the wind in the south showed up the controloing of CHL-a by the positive correlation that CHL-a and wind had during the blooms (0.740). Interannual variations are computed as monthly anomalies relative to the 1998-2009 monthly climatology. In this way, the effect of co-variation between different variables on the seasonal time scale is minimized, The anomaly data showed clear inter-annual variations in almost all parameter and zones. Strong co-variations between CHL-a and the physical parameters showed that physical process have effect on the interannual changes in the phytoplankton blooms in the Red Sea. Few highly anomalous years in some of the parameters produce a weak long-term (1998-2009) trends. Such as, in the southern zone of the Red Sea when the value of R2 =0.0157 according the high value of CHL-a in 2008 and 2009 approximately 0.28 mg/m3 for both of them. The value of R2 becomes 0.0009 when these two years have been removed.
  • Wave runup estimates at gentle beaches in the northern Indian Ocean

    Abdalazeez, Ahmed (2012)
    The aim of this study is to estimate the wave runup on selected beaches around the northern Indian Ocean. The runup has been estimated using ERA-Interim, which is the latest global atmospheric re-analysis produced by the European Center for Medium-Range Weather Forecasts (ECMWF). ECMWF uses the global Wave Model (WAM) model to calculate two dimensional wave spectra. The distances between the model grid points and the beaches have been calculated by a great circle calculator. The beach slopes have been calculated by Google Earth for all locations, except Maldives beach, which was assumed as an imaginary beach because the method of calculating the slope could not be used there. The significant wave height as well as the peak wave period at the grid points are assumed to be the same at the beach. The most frequent estimated runup is between 0.5 m and 1.0 m, which is produced by swell coming from the southern Indian Ocean for all locations except Sri Lanka, India and Maldives shores, where the most frequent runup value is less than 0.5 m. However, the extreme wave runup occurs with the largest wave heights during summer monsoon in July. Generally, the high wave height depends on wind speed. The mean elevation of the runup for all locations is 0.56 m. It is comparable to the measured values obtained by (Stochdon et al., 2006) at several beaches in USA and the Netherlands who found the mean value of dissipative sites (84 cm) for all experiments.
  • Photooxidation of Dimethylnaphthalene in Deionized water, Red Sea Arti cal water, and Red Sea Natural water

    Ali, Aasim (2012)
    Red Sea water samples were collected from the Sudanese coast at depths of 10 meter during June 2011 and analyzed for major and trace metals in addition to some inorganic anions. Sodium Na, potassium K, strontium Sr, magnesium Mg, calcium Ca, sulfur S, iron Fe, zinc Zn, manganese Mn, nickel Ni, copper Cu, cadmium Cd, cobalt Co, lead Pb, arsenic As, barium Ba, chromium Cr, europium Eu, lanthanum La, silicon Si, and titanium Ti were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES) to determine their existing concentration, their distribution patterns, study the level of contamination in the Red Sea Sudanese coastal water, and the data of the analysis was used in the preparation of the Red Sea arti cial water which was used in the photooxidation of 1,8-dimethylnaphthalene to study the salt e ect on the photooxidation of 1,8-dimethylnaphthalene in Red Sea water. tion patterns and. The inorganic anions, sulfate, chloride, and bromide were determined using ion chromatography (IC). The averages concentrations in ppm (mg/L) of major metals , Na, Mg, Ca, and K are 11870.25, 1449.2, 468.967, and 388.955 respectively. The results shown a small range of variation and regional irregularities. The results also revealed a very high concentration of sodium, and high concentration of magnesium and calcium. In addition to Copper and titanium which was not detected or has concentrationbelow thedetection limit, Arsent (As), Cobalt (Co), Chromium (Cr), Lanthanium(La), and Euribium (Eu) were all not detected, or their concentrations in the Red sea coastal water are below the detection limit of the instrument, hence,preconcentration should be done.The averages concentrations of trace metals in ppm (mg/L), B, Ba, Fe, Li, Mn, Si, Sr, Zn are 4.1935, 0.005515, 0.02524, 0.25073, 0.000085, 0.0656, 7.59765, and 0.006795 respectively. These results revealed . The results shown a small concentration of Sr and this decrease in Sr may be due to the presence of Acantharians. Ba, Sr, Si and Li are not signi cantly di erent in all areas Indicating no distinct concentration gradient. The concentration of iron Fe in Sudanese Red Sea coastal water is high and this increase in concentration can be due to the suspended particles in Sudanese Red Sea because it was not ltered or due to the pollution because also the concentration of Zn in this study is high. The averages concentrations in ppm (mg/L) of chloride, sulfate, and bromide are, 23240.515,3138.26025, and 61.795 respectively. The results show a small range of variation and regional irregularities. Also, the concentration of chloride is signi cantly. The concentration of sulfate is high. Thus, the high salinity of Red Sea coastal water is due to high concentration of sodium and chloride ions only. Photochemical experiments on the photooxidation of 1,8-dimethylnaphthalene (1,8 DMN) under arti cial sunlight and natural sunlight in deionized water, Red Sea natural water, North Sea natural water, and Red Sea arti cial water, revealed that the photooxidation of 1,8-DMN does not occur in the absence of light at 8C unless the temperature of the media is 35 Cor greater. The results shown that the e ciency of the photooxidation of 1,8-DMN is low and depend on the light intensity, and photosensitizes. The soluble fraction from the Sudanese heavy crude oil was identi ed.
  • Factors controlling the total alkalinity in the Arabian Sea and Red Sea

    Elageed, Salma (2010)
    Based on data obtained during the Geochemical Ocean Section Study (GEOSECS)1977, Mer Rouge (MEROU) 1982, and US Joint Global Ocean Flux (JGOFS)1995 studies we have analyzed the processes controlling the total alkalinity (TA) of the whole water column in the Arabian Sea and the Red Sea. The main processes important for the TA variability in area of study are salinity variations, soft tissue production, calcium carbonate formation and dissolution, and sedimentation. For the subsurface waters different processes dominate in the different basins. Regarding spatial variations in surface TA, maximum values occur in the Red Sea and minimum in the upwelling region along the Omani coast in the Arabian Sea. These variations are mainly associated with physical processes that control salinity. Alkalinity variations were decomposed to contributions arising from salinity variations ( TAs), organic matter production/remineralisation ( TAorg), and production/dissolution of calcium carbonate 􀀀 TACaCO3 . Positive values resulted for the processes that increase TA whereas negative values resulted for the processes that decrease TA. In the upper 200 m of the water column, ( TAs) was found to be 70 mol kg􀀀1 and 121 mol kg􀀀1 for the Arabian Sea and the Red Sea, respectively. Below the 200 m depth the TAs was 45 mol kg􀀀1 and 6 mol kg􀀀1 for the Arabian Sea and the Red Sea respectively. TAorg was maximum in surface 􀀀 24 mol kg􀀀1 for both Seas. For depths below 200 m, TAorg was between 􀀀10 and 0 mol kg􀀀1 in the Arabian Sea, and between 0 and 10 mol kg􀀀1 in the Red Sea. Values for TACaCO3 were around 0 mol kg􀀀1 in the surface in both ii regions, but TACaCO3 increased nearly linearly with depth in the Arabian Sea until it reached and stabilized to values around 150 mol kg􀀀1 at about 3000 m. The increase was due to dissolution of calcium carbonate (CaCO3) as the Arabian Sea was found to be undersaturated with respect to aragonite and calcite around 400 and 3000 m, respectively. Conversely, the level of undersaturation was never reached in the Red Sea. Thus,sedimentation of CaCO3 out of the water column was possible in the Red Sea. The fact that TACaCO3 decreased and stabilized to a value of 􀀀40 mol kg􀀀1 at about 500 m depth in the Red Sea suggested that CaCO3 formation and sedimentation removed TA from the water column.
  • Tide analysis In The Red Sea; In Gizan and Port Sudan

    Knut Barthel; Eltaib, Elfatih (2010)
    Tide gauge measurements recorded at two stations in the Red Sea, at Port Sudan from 1986 - 1994 and at Gizan for the period of 1992 - 1994 are used to analyze the sea level changes and tide along the east and west coast of the Red Sea, using the harmonic analysis (t tide). Meteorological parameters during the same period are used to study the response of the sea level and residual sea level to local and global forcing. The relation between sea level and forces are examined using the correlation and cross covariance analysis. The correlation and cross-covariance coe cients between sea level and sea level pressure at Port Sudan indicate that the sea level responds to atmospheric pressure as non-inverse barometer. The linear trend for the coastal area shows a sea level increases by 1:2 mm per year compared to 5:4 1:2 mm per year decrease for the period 1962 - 1979 at Port Sudan, but in good agreement with global mean sea-level rise of 1:5 0:4 mm per year [12]. Harmonic analysis (t tide) reveals the presence of a semi-annual and the annual components, with amplitudes 5:7 cm and 11:6 cm respectively. The spectral analysis shows the dominant tide at Port Sudan is diurnal tide, and in Gizan is found to semidiurnal tide. The magnitude of the tidal signal at Port Sudan is weak compared to that of Gizan, and that is because Port Sudan is located close to the amphidromic point of the semidiurnal constituent M2.