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1

Reproductive features of Gerres longirostris Lacepède, 1801 (Perciformes: Gerreidae) off the Red Sea coast of Jeddah, Saudi Arabia

Gabr Mohamed Hosny, Al-Harbi Mamdoh Ali, Sumon Md Afsar Ahmed

Oceanological and Hydrobiological Studies

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2024

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Vol. 53, No. 2

164--176

EN

Sustainable management and conservation strategies are crucial for any species of Gerreidae. Without comprehensive research on population biology, maintaining a balance between having healthy natural stocks and the socio-economic benefit of fisheries is difficult. Therefore, we studied some aspects of the biology of Gerres longirostris based on 474 specimens collected from the Red Sea (Jeddah coast, Saudi Arabia). The overall sex ratio of males to females was found to be 1:1.52, which was significantly different from the expected ratio of 1:1 (p < 0.05). Histological analysis of ovaries and testes and monthly variations in GSI values for G. longirostris indicated that spawning occurs between March and June, with a peak in GSI in May, and the trend was similar for both sexes. Size at 50% sexual maturity was estimated at 19.8 cm for females and 20.2 cm for males. The maximum batch and relative fecundity were estimated at 315,210 ova, 10,832 ova/cm, and 1068 ova/g, respectively. Batch fecundity and relative batch fecundity were significant correlated with total length (TL, cm) and body weight (BW, g) at p < 0.05. Histological examination of gonads revealed that their maturation in this species is asynchronous, with different developmental stages of oocytes at the same time, which indicates that the species is a multiple-batch spawner with indeterminate fecundity.

2

Biological threats in diving locations

Lewicka M., Zawadzka M., Siermontowski P., Giermaziak W., Henrykowska Gabriela

Polish Hyperbaric Research

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2022

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nr 1(78)

87--100

EN

Diving locations can pose various risks to divers. Health problems can be caused by, among other things, pathogenic microorganisms as well as flora and fauna endemic to the region. This paper discusses the consequences of exposure to biological pathogens endemic to the Red Sea region and possible preventive measures that can be taken before and during a diving expedition.

PL

Akweny nurkowe mogą stwarzać różnego typu zagrożenia dla osób nurkujących. Problemy zdrowotne mogą być spowodowane m. in. drobnoustrojami chorobotwórczymi oraz florą i fauną występującymi endemicznie w danym regionie. W pracy omówiono konsekwencje narażenia na biologiczne czynniki chorobotwórcze, endemicznie występujące w rejonie Morza Czerwonego oraz możliwości działań profilaktycznych przed i podczas wyprawy nurkowej.

3

Effects of diet quantity on growth performance of juvenile sea cucumbers Holothuria scabra

Al-Harbi Mamdouh

Oceanological and Hydrobiological Studies

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2022

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Vol. 51, No. 2

158--166

EN

Sea cucumbers are in high demand in the world market due to their nutritional and medicinal values. In this study, the growth performance of juvenile sea cucumbers Holothuria scabra fed with different proportions of two feeds was analyzed. Commercially available sea cucumber feed (feed-A) and formulated feed (feed-B) were used for the experiments. Animals fed with 2% feed-A showed a negative growth rate. Maximum growth was observed in animals fed with 8% feed-A and feed-B. While feed-A treated groups showed significant variation (P < 0.05) in growth performance between different percentages of diets, feed-B treated animals showed no such variation. Feed-B treated animals showed higher growth rates compared to feed-A treated sea cucumbers. Water quality parameters and anoxic conditions of the soil in culture tanks did not change due to the higher percentage of feeds. In conclusion, this study showed that diet percentage is an important factor for the optimum growth of sea cucumbers.

4

Assessment of heavy metal pollution in seawater, benthic flora and fauna and their ability to survive under stressors along the northern Red Sea, Egypt

Salah-Tantawy Ahmed, Mahdy Aldoushy, Dar Mahmoud A., Young Shuh-Sen, Abdelreheem Abdelbaset M. A.

Oceanological and Hydrobiological Studies

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2022

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Vol. 51, No. 4

355--370

EN

The purpose of this study was to assess the north coasts of the Egyptian Red Sea, including Ras Gharieb, Hurghada, Safaga and Qusier, by evaluating the heavy metal pollution in seawater and benthic flora and fauna in the winter and summer of 2016. The concentrations of heavy metals (Fe, Mn, Zn, Cu, Ni, Cd and Pb) were analysed with an atomic absorption spectrophotometer. The results revealed that the Fe levels in the seawater ranged from 7.86 and 27.95 μg l-1, while the Zn concentrations fell between 1.83 and 5.63 μg l-1. In contrast, the recorded values of Mn, Cu, Ni, Pb and Cd in the seawater were minimal at the study sites. Regarding the biota samples, Porifera species were more adaptable than others to an accumulation of most metals in their tissues. Furthermore, seaweeds and seagrasses demonstrated remarkable adaptation in highly polluted regions, especially those with high turbidity, landfilling, sedimentation and high eutrophication rates – much more than the benthic fauna. Our research highlights the critical need for strict regulation of metal emissions in these coastal regions.

5

Antifouling activity of bacterial extracts associated with soft coral and macroalgae from the Red Sea

Tunkal Rabab Ibrahim, Jamal Mamdoh T., Abdulrahman Idris, Pugazhendi Arulazhagan, Satheesh Sathianeson

Oceanological and Hydrobiological Studies

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2022

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Vol. 51, No. 4

325--336

EN

In marine environments where biofouling occurs and has an impact on the maritime economy and environment, compounds that inhibit the attachment, growth and survival of microorganisms in a biofilm complex as well as settlement of larvae are considered potential antifouling compounds. In this study, the extracellular metabolites from two surface- associated bacteria isolated from soft coral and macroalga were evaluated for antibiofilm and antisettlement activity. The bacteria were identified using 16S rRNA gene sequencing, and the culture supernatant extract of each strain was evaluated for antibiofilm activity. The compounds present in the extracts were analysed using GC-MS. The two bacterial strains were identified as Bacillus licheniformis MBR1 and Vibrio alginolyticus MBR4 for the isolates from soft coral and macroalgae, respectively. The extracts inhibited the growth of biofilm-forming bacteria, biofilm formation and barnacle larval settlement. The GC-MS analysis of the extract detected the presence of compounds such as tetrapentacontane, octadecanoic acid, 2,3-dihydroxypropyl ester, hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester and 17-pentatriacontene. The results of the study show that extracellular metabolites of the bacteria associated with marine organisms could be used as natural antifouling compounds to control biofouling.

6

Combining multivariate statistical analysis to shed light on distribution and interaction of halogens in two economic ports along Red Sea Coast in Egypt

Zokm Gehan M. El, El-Said Ghada F., El Sayed Abeer A.M.

Oceanologia

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2022

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No. 64 (1)

103--106

EN

Mabahiss Bay and Safaga Bay are two important ports along the Red Sea coast of Egypt. The present study is the first to monitor halogen concentrations in these two ports. Certain halogens (F, Cl, Br and I) in coastal waters and sediments exhibited different behaviors. Fluoride (1.92–8.31 mg/L and 0.34–1.24 mg/g), chloride (20.76–22.68 g/L and 0.38–8.31 mg/g), bromide (95.90–151.84 mg/l and 6.66–50.61 mg/g), and iodide (2.77–39.19 μg/L and 1.71–3.76 μg/g) appeared in the seawater and sediments of Mabahiss Bay, respectively. In Safaga Bay, F, Cl, Br and I yielded ranges of (1.80–10.15 mg/L and 0.14–0.74 mg/g), (21.47–22.57 g/L and 0.68–1.42 mg/g), (15.98–146.51 mg/L and 6.13–74.59 mg/g) in seawater and sediments, respectively. In Mabashis Bay exclusively, the bromide and iodide levels in seawater increased significantly, and the sediments were vice versa. The average fluoride value in the two ports' seawater was higher than that in the unpolluted Mediterranean Sea. In contrast, the average bromide content in Mabahiss Bay seawater exceeded the Mediterranean Sea level. The seawater chloride content of the two ports was within the Mediterranean seawater's value, but the iodide concentration was lower than that of the unpolluted seawater. The application of different multivariate statistical techniques showed that halogen's distribution and halogen's geochemical characteristics control interaction in each region, ground flux, and proximity to human sources.

7

Spatio-temporal variation of microphytoplankton communities in Obhur Creek, the central Red Sea

El-Sherbiny Mohsen M., Al-Harbi Mamdouh A., Kumar Anand J.

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 1

98--114

EN

The abundance and distribution of microphyto-plankton and related physicochemical factors were assessed monthly in Obhur Creek, the central Red Sea. Sampling was carried out near the entrance, the middle and end parts of the creek. During the course of the present study, the Red Sea was characterized by predominantly oligotrophic conditions. Nutrient concentrations were relatively higher in the end part of the creek compared to the two other study sites. Chlorophyll a was also low throughout the year (average: 0.35 ± 0.32 mg m−3), except in May when it showed clear peaks at open-water and middle sites of the creek (1.85 and 1.04 mg m−3, respectively). Phytoplankton abundance followed a similar pattern to that of chlorophyll a with considerably higher abundance at these sites in May (3063.27 × 103 and 1082.34 × 103 individuals m−3, respectively). This unusually higher abundance was mostly due to the proliferation of the diatom Pseudo-nitzschia cf. delicatissima (Cleve) Heiden. Silicate concentrations were statistically significantly correlated with total phytoplankton. A total of 220 phytoplankton species were recorded during the study period (117 diatoms, 99 dinoflagellates and four cyanophytes). Diatoms dominated in the phytoplankton abundance (75%) and were followed by dinoflagellates (20%), while cyanophytes accounted for a minimal proportion. Of all phytoplankton species observed during the study, 21 diatom and four dinoflagellate species were considered as new records for the Red Sea, and two diatom and 14 dinoflagellate species were listed as harmful algal species worldwide.

8

Effects of copper and cadmium on physiology and antifouling defense of the marine macroalga Ulva reticulata

Al-Khaldi Wejdan Ahmed, Al Solami Lafi, Satheesh Sathianeson

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 2

184--197

EN

Heavy metals are major stressors for benthic macroalgal communities in marine ecosystems. In this study, the effects of copper and cadmium on some physiological parameters along with antifouling defense of the marine macroalga Ulva reticulata were assessed under laboratory conditions. Macroalgal samples were treated with three concentrations (1 mg l−1, 3 mg l−1 and 5 mg l−1) of copper and cadmium for 2 and 7 days. After treatment, algal samples were analyzed for chlorophyll-a, carotenoid, total polyphenol and total antioxidant capacity. Also, algal extracts were tested against biofilm-forming bacteria strains to understand differences in antifouling activity. The results indicated that exposure of U. reticulata to copper and cadmium, on the one hand, induced protective mechanisms such as total phenol production and antioxidant capacity against metal stress and, on the other hand, reduced photosynthesis. While the extract obtained from control algal samples showed a strong inhibitory effect on the growth of biofilm-forming bacteria, treatment with heavy metals resulted in reduced antibiofilm activity. In general, the results revealed that exposure of macroalgae to heavy metals can affect antifouling defense traits in addition to changes in photosynthetic pigment content.

9

Distribution and community structure of microphytoplankton in relation to increasing anthropogenic impact along coastal waters of Jeddah, the central Red Sea

Al-Amri Aisha A., Qari Huda A., El-Sherbiny Mohsen M.

Oceanological and Hydrobiological Studies

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2020

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Vol. 49, No. 2

193--205

EN

Seasonal distribution and diversity of surface phytoplankton have been studied in relation to anthropogenic activities at seven locations along the coastal waters of Jeddah, Saudi Arabia in 2017. The concentration of nitrite, nitrate, ammonia, phosphate and silicate varied over wide ranges: 0.04–20.27, 0.05–29.3, 0.22–78.16, 0.02–25.90 and 43–24.50 μmol l-1, respectively. Inorganic nutrients, phytoplankton biomass and density were at eutrophic levels at two lagoon locations (4 and 5), while other coastal locations showed oligotrophic characteristics of the Red Sea. Phytoplankton biomass was positively correlated with all measured inorganic nutrients. The total phytoplankton density varied between 52.4 × 103 and 40800 × 103 cells m-3 (average 6249.9×103 ± 10797×103 cells m-3). A total of 174 species of phytoplankton (95 diatoms, 75 dinoflagellates, 3 cyanophytes and 1 silicoflagellates) were recorded in this study, with the dominance of diatoms (95.1%). Higher densities observed at lagoon locations were mainly due to the proliferation of the diatom species Skeletonema costatum and Chaetoceros decipiens. In terms of diversity, dinoflagellates were more numerous than diatoms in July, otherwise mostly diatoms dominated. On the other hand, cyanophytes were more abundant in November. Based on the present study, anthropogenic activities (especially sewage effluent) in Jeddah coastal waters had a significant impact on the phytoplankton densities and diversity.

10

Investigating the Role of Atmospheric Variables on Sea Level Variations in the Eastern Central Red Sea Using an Artificial Neural Network Approach

Zubier Khalid M., Eyouni Lina S.

Oceanologia

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2020

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No. 62 (3)

267--290

EN

Atmospheric variables play a major role in sea level variations in the eastern central Red Sea, where the role of tides is limited to 20% or less. Extensive analysis of daily-averaged residual sea level and atmospheric variables (atmospheric pressure, air temperature, wind stress components, and evaporation rate) indicated that sea level variations in the eastern central Red Sea are mainly contributed to by the seasonal and weather-band variations in the utilized atmospheric variables. The Non-linear Auto-Regressive Network with eXogenous inputs (NARX), a type of Artificial Neural Network (ANN), was applied to investigate the role of the atmospheric variables on the sea level variations at the eastern central Red Sea. Forced by time-delayed daily-averaged observations of atmospheric variables and residual sea level, the constructed NARX-based model showed high performance in predicting the one-step-ahead residual sea level. The high performance indicated that the constructed model was able to efficiently recognize the role played by the atmospheric variables on the residual sea level variations. Further investigations, using the constructed NARX-based model, revealed the seasonal variation in the role of the atmospheric variables. The study also revealed that the role played by some of the atmospheric variables, on sea level variations, could be masked by the role of one or more of the other atmospheric variables. The obtained results clearly demonstrated that this neurocomputing (NARX) approach is effective in investigating the individual and combined role of the atmospheric variables on residual sea level variations.

11

Evaluation of the carbon sequestration capacity of arid mangroves along nutrient availability and salinity gradients along the Red Sea coastline of Saudi Arabia

Shaltout Kamal H., Ahmed Mohamed T., Alrumman Sulaiman A., Ahmed Dalia A., Eid Ebrahem M.

Oceanologia

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2020

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No. 62 (1)

56--69

EN

In the present work, we assessed the carbon sequestration capacity of mangrove forests (Avicennia marina) in relation to nutrient availability and salinity gradients along the Red Sea coast of Saudi Arabia. This was achieved through estimating the sediment bulk density (SBD), sediment organic carbon (SOC) concentration, SOC density, SOC pool, carbon sequestration rate (CSR) and carbon sequestration potential (CSP). The present study was conducted at 3 locations (northern, middle and southern), using 7 sites and 21 stands of mangrove forests (A. marina) along ∼1134 km of the Red Sea coastline of Saudi Arabia (from Duba in the north to Jazan in the south), all of which are in an arid climate. The correlation coefficients between the water characteristics and the first two Canonical Correspondence Analysis (CCA) axes indicated that the separation of the sediment parameters along the first axis were positively influenced by TDS (total dissolved solids) and EC (electric conductivity) and were negatively influenced by total N and total P. On the other hand, the second axis was negatively correlated with total N, total P, EC and TDS. The SOC pools at the northern (10.5 kg C m−2) and southern locations (10.4 kg C m−2) were significantly higher than the SOC pool at the middle location (6.7 kg C m−2). In addition, the average CSR of the northern (5.9 g C m−2 yr−1) and southern locations (6.0 g C m−2 yr−1) were significantly higher than they were in the middle location (5.0 g C m−2 yr−1).

12

Recruitment patterns of the solitary ascidian Phallusia nigra Savigny, 1816 on artificial substrates submerged in the central Red Sea, Saudi Arabia

Al-Sofyani Abdul Mohsin A, Satheesh Sathianeson

Oceanological and Hydrobiological Studies

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2019

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Vol. 48, No. 3

262--269

EN

The solitary ascidian Phallusia nigra is commonly found on hard substrates along the Jeddah coastal waters of the central Red Sea. In this study, the recruitment pattern of P. nigra on artificial substrates was assessed in relation to their type, surface color and orientation. The results showed a higher recruitment rate of the ascidian species on concrete and dark panels. The abundance of the ascidian on test panels varied between the four seasons. The orientation (vertical or horizontal) of the panels did not show any major difference in the recruitment. Significant effects of light intensityon the recruitment of P. nigra were observed on test panels, with higher abundance on panels submerged in the shade. In conclusion, this study clearly indicates the importance of the type and color of substrates in the recruitment of ascidians on artificial materials.

13

Recent sea surface temperature trends and future scenarios for the Red Sea

Shaltout Mohamed

Oceanologia

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2019

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No. 61 (4)

484--504

EN

The current paper analyses the recent trends of Red Sea surface temperature (SST) using 0.25° daily gridded Optimum Interpolation Sea Surface Temperature (OISST) data from 1982 to 2016. The results of 3 different GFDL (Geophysical Fluid Dynamics Laboratory) model simulations are used to project the sea surface temperature (hereafter called Tos) under the four representative concentration pathway scenarios through 2100. The current research indicates that the spatially annual mean (from 1982 to 2016) Red Sea surface temperature is 27.88 ± 2.14°C, with a significant warming trend of 0.029°C yr-1. The annual SST variability during the spring/autumn seasons is two times higher than during the winter/summer seasons. The Red Sea surface temperature is correlated with 13 different studied parameters, the most dominant of which are mean sea level pressure, air temperature at 2 m above sea level, cross-coast wind stress, sensible heat flux, and Indian Summer Monsoon Index. For the Red Sea, the GFDL-CM3 simulation was found to produce the most accurate current SST among the studied simulations and was then used to project future scenarios. Analysis of GFDL-CM3 results showed that Tos in the Red Sea will experience significant warming trends with an uncertainty ranging from 0.6°C century-1 to 3.2°C century-1according to the scenario used and the seasonal variation.

14

Meiobenthic assemblage of the grey mangrove (Avicennia marina) along the Saudi Arabian coast of the Red Sea with emphasis on free-living nematodes

Al-Sofyani A., El-Sherbiny M.

Oceanological and Hydrobiological Studies

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2018

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Vol. 47, No. 4

359--375

EN

Spatial variability in the population density of meiofauna and the assemblage of free-living marine nematodes was studied at 20 mangrove sites located along the Saudi Arabian coast of the Red Sea. The total abundance of meiofauna varied between the locations and ranged from 119 to 1380 ind. 10 cm-2. A total of seven main taxa were recorded. Nematodes dominated (64.3%) in all sediment samples. They were followed by harpacticoid copepods (13.2%) and polychaetes (12.9%) with significant differences in their density between the locations surveyed (p < 0.001). The Pearson correlation analysis showed significant positive correlations between the sand fraction and nematodes, harpacticoid copepods and turbellarians. Twenty-five genera of free-living nematodes belonging to 15 families were recorded in the study area. Microlaimidae were the most abundant family, while Xyalidae, Desomodridae and Chromidoridae were the most diverse families. Microlaimus, Halalaimus and Terschellingia were the most frequent genera. ANOSIM values obtained for the distribution of different nematode genera in various habitats showed no significant differences. Feeding types of different nematode genera were also documented and the epistrate feeders along with the deposit feeders were found to be the common feeding types in the present study.

15

Microfouling development on artificial substrates deployed in the central Red Sea

Balqadi A. A., Salama A. J., Satheesh S.

Oceanologia

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2018

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No. 60 (2)

219--231

EN

Microfouling is the initial step in the growth of biofouling on hard substrata submerged in marine waters. In this study, microfouling development on nylon nets submerged in the central Red Sea coast of Saudi Arabia was analyzed during the winter and summer seasons for a period of 5 days each. The results showed a well-established biofilm community on nylon nets submerged for 24 h, with bacteria and diatoms being the primary colonizers. Protein was the major organic component of the biofilm that developed on the nylon nets during the winter and summer seasons. Navicula spp., Nitzschia spp., Cylindrotheca spp., and Pluerosigma spp. were the dominant diatom species settled on the nylon nets. Pseudoalteromonas shioyasakiensis, Planomicrobium sp., Vibrio harveyi and Pseudoalteromonas rubra were the dominant bacteria isolated from the nylon nets. While the abundance of bacteria showed a positive correlation with the nutrient concentration of the biofilm during both winter and summer seasons, diatom density exhibited a significant positive relationship with the biofilm nutrients during the winter season only. The results also revealed significant seasonal variations in the abundance of microfouling organisms and accumulation of nutrients on nylon nets.

16

Ecological assessment of heavy metals in the grey mangrove (Avicennia marina) and associated sediments along the Red Sea coast of Saudi Arabia

Alzahrani D. A., Selim E.-M. M., El-Sherbiny M. M.

Oceanologia

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2018

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No. 60 (4)

513--526

EN

Mangroves play an integral role as a metal accumulator in tropical and subtropical marine ecosystems. Twenty-one sets of sediment samples and portions of mangroves were collected along the Saudi Arabian coast of the Red Sea to assess the accumulation and ecological risks of heavy metals. Results showed that the following mean concentrations of heavy metals in sediments: Cr (46.14 μg g−1 ± 18.48) > Cu (22.87 μg g−1 ± 13.60) > Ni (21.11 μg g−1 ± 3.2) > Pb (3.82 μg g−1 ± 2.46) > Cd (0.75 μg g−1 ± 0.87). The maximum concentrations of the studied metals were above the threshold effect level, indicating a limited impact on the respective ecosystems. The maximum concentration of Cd exceeded its toxic effect threshold, revealing a harmful risk to biota in the sediments. Based on metallo-phytoremedation, biological concentration factors were >1, suggesting that Avicennia marina can accumulate heavy metals, especially Cr and Pb. The translocation factor was above the known worldwide average. The geo-accumulation index revealed that sediments in mangrove areas ranged from moderately to heavily contaminated with Cd at Al-Haridhah and moderately contaminated at South Jeddah, Rabigh, Duba, and the wastewater treatment station near Jazan. The ecological risk index revealed that Cd could pose a relatively very high risk to the mangrove ecosystem. The present study emphasized the possibility of establishing a framework for the management of the coastal aquatic ecosystems along the Red Sea coast of Saudi Arabia.

17

Spatial and temporal distribution of heavy metals in coastal core sediments from the Red Sea, Saudi Arabia

Al-Mur B. A., Quicksall A. N., Al-Ansari A. M. A.

Oceanologia

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2017

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No. 59 (3)

262--270

EN

Jeddah is the most industrialized city on the west coast of Saudi Arabia and is under increasing influence of human activities. Heavy metals data were obtained from four near-coast Red Sea sediment cores in close proximity to Jeddah. Chromium, manganese, iron, copper, zinc, and lead were analyzed from depth-resolved sections of each core via heavy acid digestion and inductively coupled plasma-mass spectrometry (ICP-MS). The average concentrations of all four sites were 245.96 mg kg−1, 478.45 mg kg−1, 8506.13 mg kg−1, 251.82 mg kg−1, 623.09 mg kg−1, and 362.75 mg kg−1, respectively. The depth-resolved results showed that highest concentrations of Mn, Cu, and Pb were found in the top 15 cm of the core profile distributions compared to other depth sub-samples. Heavy metal concentrations in core sediments are increased near central Jeddah and have become higher in recent years. The results of enrichment factor calculations indicate little anthropogenic supply of Mn and Cr while Pb, Zn, and Cu show strong anthropogenic input. The Pollution Load Index was higher in the two sites closer to central Jeddah where power and desalination plants and wastewater release are known. This indicates that the area has suffered from heavy metal pollution compared to other non-industrialized sites in the Red Sea. Heavy metal contaminations due to anthropogenic activity should be taken into account to protect the Red Sea during future growth. The results of this work should be considered as a baseline for heavy metals monitoring in the sediments of the Red Sea coast near Jeddah, Saudi Arabia.

18

Geochemical signatures of pervasive meteoric diagenesis of Early Miocene syn-rift carbonate platform, Red Sea, NW Saudi Arabia

Al-Ramadan K.

Geological Quarterly

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2017

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Vol. 61, No. 1

239--250

EN

Different diagenetic environments have been recognized in the Early Miocene carbonate platform of Musayr Formation in the Red Sea rift area. Early marine diagenesis includes micritisation that occurs as thin envelope around skeletal and non-skeletal grains in low-energy mud dominated facies and isopachous fibrous calcite in high-energy grain-dominated facies. Pervasive meteoric water diagenesis resulted in cementation of the carbonates by coarse-crystalline blocky-drusy calcite and meniscus cements. Depletion of oxygen (avg. –9.08‰), carbon (avg. –1.6‰) isotopes and trace elements concentrations (avg. values of Fe: 1387 ppm; Mn: 1444 ppm; Sr: 419 ppm; Na: 1194 ppm) in conjunction with negative correlation between Mn2+ and oxygen isotope data suggest variable degrees of fluid-rock interactions and pervasive meteoric diagenesis. The formation of meteoric diagenesis in the Musayr Formation can be explained by two subsequent mechanisms: (1) the presence of meteoric lenses during the time of deposition might have been associated with active freshwater input from the hinterland (NE) due to fall in the relative sea level; (2) later uplift episode during Plio-Pleistocene may have also contributed to the pervasive meteoric diagenetic alterations of the carbonates of the Musayr Formation. The first mechanism is supported by the cement stratigraphy where the blocky-drusy cements postdate the meniscus cement. The latter mechanism seems to have more pronounced effect on the alteration of Musayr carbonate sequence by observing the occurence of late cements such as blocky calcite in most of the samples. The impact of meteoric diagenesis on the studied samples suggest that dissolution is less severe than cementation, hence the visible porosity is very low. Understanding the timing of meteoric diagenesis provides useful information about the reservoir quality distribution in syn-rift carbonate sequences.

19

Heavy metals contamination and distribution of benthic foraminifera from the Red Sea coastal area, Jeddah, Saudi Arabia

Youssef M.

Oceanologia

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2015

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No. 57 (3)

236--250

EN

The distribution of benthic foraminifera was studied in two stations in the coastal area, located around Jeddah, Red Sea coast, Saudi Arabia. Thirty-three species belonging to 15 genera, 14 families and three suborders were recorded in twenty samples. Some foraminiferal tests display abnormalities in their coiling, general shape of chambers and apertures. On the other hand, concentrations of Fe, Mn, Zn, Cu, Pb, Ni, Cr, and Cd were measured in the tests of the two most common living species of benthic foraminifera (Sorites marginalis and Peneroplis planatus). Significant spatial differences in the metal concentrations of benthic foraminifera were recorded at the two sites. Benthic foraminifera yielded significantly high concentrations of Fe, Mn, Pb and Cu, which may attribute to anthropogenic activities at the studied coastal areas. The anthropogenic activities have a considerable impact, besides other factors, in the abnormalities of foraminiferal test.

20

Larval development and settlement of the barnacle Amphibalanus amphitrite from the Red Sea : Influence of the nauplii hatching season

Al-Aidaroos A.M., Satheesh S.

Oceanological and Hydrobiological Studies

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2014

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Vol. 43, No. 2

170--177

EN

Barnacle Amphibalanus amphitrite adults were collected from the Jeddah coast of the Red Sea during different seasons. The nauplii released by adults in autumn, winter, spring and summer were reared under laboratory conditions to know the larval development duration and settlement in relation to the hatching season. The nauplii reared during winter (11 days) and autumn (13 days) took longer to reach the cypris stage compared to nauplii reared in summer (6 days) and spring (7 days). The most successful settlement of larvae was observed in spring and summer and the least successful — in winter. The observations of gonads showed that summer and spring are the active breeding season for A. amphitrite in the Red Sea. The results of this study indicated that the nauplii hatching season plays a significant role in the larval development and settlement of barnacles in the Red Sea.