Northwestern Arabian Gulf Research Articles

Health risk assessment and contamination of lead and cadmium levels in sediments of the northwestern Arabian Gulf coast

This environmental assessment focuses on the coastal sediments of the Al-Khafji area in the Saudi Arabian Gulf, with an analysis of the human health risks posed by lead (Pb) and cadmium (Cd) contamination. Single and integrated indices were used to detect contamination and evaluate these metals' non-carcinogenic and carcinogenic impacts on adults and children through ingestion, dermal contact, and inhalation pathways. Sediment quality guidelines and contamination indices indicated the absence of significant contamination levels. The moderate contamination observed in scattered samples did not imply adverse biological effects due to the presence of these two metals in Al-Khafji sediments. The average values of the chronic daily intake (CDI) for both Pb and Cd were higher in children than adults across all three pathways, with ratios of 9.4, 4.7, and 4.7 folds, respectively. The hazard index (HI) values for Pb and Cd were below 1, confirming that the sediments of Al-Khafji are considered acceptable and safe in terms of these potentially toxic elements (PTEs). The average lifetime cancer risk (LCR) values for Pb and Cd were higher in children compared to adults, with ratios of 9.3 and 9.4 folds, respectively. However, all detected LCR levels do not represent a potential carcinogenic health hazard. Nevertheless, a regular monitoring program aimed at detecting early signals of environmental health depletion is recommended.

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Data from the current study was used to analyse the impact of marine heat waves on the quantity and distribution patterns of Iraqi marine fisheries following the recent change in the climate of the northwestern Arabian Gulf. The average annual water temperature and salinity were 26◦C and 38.6 psu, respectively, higher than the averages recorded during previous decades. The dissolved oxygen average was 8.65 psu, and the pH was 8.23. Principal components analysis (PCA) showed that temperature and salinity accounted for 66.93% of the effect of the studied factors, while the percentage of dissolved oxygen was 32.81% and the pH was 0.27%. The results showed a decrease in the weight, numbers, and diversity of the fish during the summer compared to the data from previous decades. Supplementary variable analysis showed that the number of species, individuals, and weights of commercial marine fisheries' catches were inversely correlated to water temperature and salinity. Autocorrelation analysis revealed temporal changes in the effect of temperature and salinity on the decline in the number of fish during the summer. It is extremely important that significant progress be made in understanding marine heat waves and the risks they pose to marine ecosystems in order to predict how these systems and the products they provide will be affected.

Molecular taxonomy of fish larvae in the Northwestern Arabian gulf: A baseline study from Kuwait's first marine protected area

Sulaibikhat Bay, a shallow embayment dominated by tides and extensive mud flats along the northern coast of Kuwait Bay, serves as a crucial nursery ground for various commercially important species of finfish and shellfish in the Northwestern Arabian Gulf (NWAG). As the location of Kuwait's inaugural marine protected area (MPA), Sulaibikhat Bay plays a vital role in fostering numerous fish and marine invertebrate species of commercial importance in the Arabian/Persian Gulf. Accurate identification of larval specimens from this habitat is essential for understanding their spawning dynamics and recruitment process. However, limitations in taxonomic identification hinder scientific understanding of fish larval recruitment. To address this, our baseline study employed an integrated taxonomic approach, combining conventional morphology with molecular techniques. Fish larvae collected from the MPA and surrounding waters in Spring (2022) were identified up to the genus and species levels using partial gene sequencing of 16 S rRNA and mitochondrial cytochrome oxidase (COI) genes. Morphological analysis indicated the prevalence of Sparidae, Sillaginidae, and Dorosomatidae families. Molecular analysis confirmed the presence of these families and identified two species, Crenidens crenidens (Sparidae) and Nematalosa nasus (Dorosomatidae), along with two genera, Diplodus sp. (Sparidae) and Sillago sp. (Sillaginidae), which exhibited maximum similarity to available COI sequences of Diplodus sargus, and Sillago maculata, respectively. This represents the first baseline molecular study on fish larvae from NWAG, laying the groundwork for future in-depth analyses with more larval specimens and spatiotemporal samplings from the entire exclusive economic zone (EEZ) of Kuwait in the Arabian/Persian Gulf.

Population ecology of the intertidal xanthid crab Leptodius exaratus (H. Milne Edwards, 1834) (Decapoda: Brachyura: Xanthidae) on rocky shores in Kuwait, Arabian (Persian) Gulf

Abstract Leptodius exaratus (H. Milne Edwards, 1834) is an exploited species that has been used as bait for recreational fishing in Kuwait. The biological and ecological aspects of the species required to manage this practice are limited. We investigated the life history and population ecology of L. exaratus in the northwestern Arabian (Persian) Gulf. The spawning season of the crab in Kuwait starts in the late spring and continues through the summer and ends in September. Fecundity is highly correlated to female body size and ranges 2,533–11,991 eggs clutch–1, with a mean number of 7,055 eggs clutch–1. Juveniles are generally recruited between July and September, with lower minor recruitment levels occurring in October and November. Growth is highly seasonal, being slow during the cold season (October-February) and high during the warmer season (March and September), with a higher growth rate in males than in females. The seasonality of growth and reproduction of L. exaratus in the region is strongly related to ambient air and water temperatures. Sexual dimorphism is highly significant between males and females with males, reaching reproductive maturity at 17.43 ± 0.53 mm carapace width (CW) and females at 9.58 ± 1.21 mm CW. The overall sex ratio for the species is 0.8:1 (males:females). Furthermore, the life span of 3–4 yr and an overall mortality slightly higher in males than in females. The results of our study could be used to determine fishery management strategies such as minimum catch sizes and closures periods. The results on life history and dynamics of the complex life cycle of L. exaratus contribute to conservation and sustainable exploitation of the species in Kuwait.

A preliminary study on benthic nutrient exchange across sediment-water interfaces in a shallow marine protected area of the Northwestern Arabian Gulf

Sedimentary processes are expected to play a crucial role in macronutrient cycling of the shallow Arabian Gulf. To investigate this aspect, sediment cores were collected from the shallow intertidal and subtidal expanses of the first Marine Protected Area (MPA) of Kuwait in the Northwestern Arabian Gulf (NAG). Porewater nutrient profiling and whole core incubation experiments were conducted to measure the nutrient fluxes, both with and without the addition of the nitrification inhibitor allylthiourea (ATU). The porewater data confirmed the potential of sediments to host multiple aerobic and anaerobic pathways of nutrient regeneration. The average (±SD) of net nutrient fluxes from several incubation experiments indicated that ammonium (NH4+) predominantly fluxed out of the sediment (3.81 ± 2.53 mmol m−2 d−1), followed by SiO44− (3.07 ± 1.21 mmol m−2 d−1). In contrast, the average PO43− flux was minimal, at only 0.06 ± 0.05 mmol m−2 d−1. Fluxes of NO3− (ranged from 0.07 ± 0.005 to 1.16 ± 0.35 mmol m−2 d−1) and NO2− (0.03 ± 0.003 to 0.71 ± 0.21 mmol m−2 d−1) were moderate, which either reduced or reversed in the presence of ATU (−0.001 ± 0.0001 to 0.01 ± 0.0001 mmol m−2 d−1 and -0.001 ± 0.0003 to 0.006 ± 0.001 mmol m−2 d−1 for NO3− and NO2− respectively). Thus, this study provides preliminary experimental evidence that nitrification can act as a source of NO3− and NO2− as well as contribute towards the relatively high concentrations of NO2− (>1 in the gulf waters.

Patterns of Abundance and Diversity of Fishes in Iraqi Estuarine and Marine Waters of the Northwestern Arabian Gulf

Patterns of Abundance and Diversity of Fishes in Iraqi Estuarine and Marine Waters of the Northwestern Arabian Gulf

An annotated checklist of the Amphipoda (Crustacea) of Kuwait, north-western Arabian Gulf

Kuwait’s intertidal and subtidal habitats were surveyed from 2013 to 2016 for amphipods, and earlier records from Kuwait and the rest of the Gulf were compared to provide the first annotated checklist of Amphipoda in Kuwait. A total of 82 sites in mainland and islands were surveyed including intertidal and subtidal zones. The resulting data identified 86 amphipod taxa belonging to 54 genera, 32 families and 3 suborders, including 20 new records to science that are currently being described. A total of 46 amphipod species, 34 genera and 19 families constituted new regional records either for Kuwait or the entire Gulf area. Information on local distribution, occurrence, and habitat are provided for each species. Within the tidal zonation, 50 species inhabited both the intertidal and subtidal areas, 19 were intertidal, 12 subtidal, and 3 species were found in the supratidal zone. Sandy and rocky shores supported the most diverse amphipod assemblages. A gradient of increasing amphipod species richness from north to south along Kuwait’s mainland coastline was revealed. The high level of regional endemism supported notable taxonomic distinction of the amphipod fauna of Kuwait from the other Gulf areas. Compositional dissimilarity among amphipod faunas increased with distance within a wide longitudinal gradient across the Gulf, Sea of Oman, and north-western Arabian Sea.

In-situ observations of swarming pelagic tunicate Pegea confoederata (Forskål, 1775) (Tunicata: Thaliacea) in coral reef habitats of Kuwait

Pelagic tunicates (order Salpida) have the highest filtration rates among filter feeding marine zooplankton. This is the first-ever in situ observation of the salp, Pegea confoederata (Forskål, 1775), in northwestern Arabian Gulf (NWAG), off Kuwait. Swarms of P. confoederata with chain-like blastozooids (∼1 ​m) and solitary oozoids were observed in offshore coral reef habitats. Coastal fishes, Diplodus sargus kotschyi and Abudefdef vaigaiensis, were observed feeding on P. confoederata tests. In Kuwait, higher summer density of phytoplankton (<20 ​μm) supports P. confoederata aggregation. Concerted studies on salps in the Arabian Gulf may offer insights into pelagic carbon cycling pathways and carbon sequestration.

Portunus pelagicus (Linnaeus, 1758) as a Sentinel Species to Assess Trace Metal Occurrence: A Case Study of Kuwait Waters (Northwestern Arabian Gulf).

Heavy metal pollution can adversely impact marine life, such as crabs, which can accumulate it in different organs and potentially transfer and biomagnify along the food chain in aquatic ecosystems. This study aimed to examine the concentrations of heavy metals (Cd, Cu, Pb, and Zn) in sediment, water, and crab tissues (gills, hepatopancreas, and carapace) of the blue swimmer crab Portunus pelagicus in the coastal areas of Kuwait, northwestern Arabian Gulf. Samples were collected from Shuwaikh Port, Shuaiba Port, and Al-Khiran areas. The accumulation of metals in crabs were higher in the carapace > gill > digestive gland, and the highest metal concentration was found in crabs collected from Shuwaikh > Shuaiba > Al-Khiran. The metal concentrations in the sediments were in the order Zn > Cu > Pb > Cd. Zn was the highest metal concentration detected in marine water sampled from the Al-Khiran Area, whereas the lowest metal was Cd sampled in water from the Shuwaikh Area. The results of this study validate the marine crab P. pelagicus as a relevant sentinel and prospective bioindicator for evaluating heavy metal pollution in marine ecosystems.

Physicochemical factors affecting chlorophyll-a concentrations in the north-western Arabian Gulf and Kuwait’s territorial waters

Physicochemical factors affecting chlorophyll-a concentrations in the north-western Arabian Gulf and Kuwait’s territorial waters

Dynamic hydrographic and water-quality variations in the northwestern Arabian Gulf, a sinking zone of reverse estuarine circulation

Continuous measurements of hydrographic, hydrodynamic, and water quality showed marked diurnal, tidal, and seasonal variabilities in Kuwait Bay, a stressed coastal system in the northwestern Arabian/Persian Gulf. Advection of water masses and seasonality in vertical mixing regulated the Bay's hydrographic and water quality properties. Intensive stratification in summer had substantial implications on the Bay environment. Kuwait Bay constantly exports dense bottom water laden with dissolved inorganic nutrients and organic matter to the central basin of the Gulf. The export was largest in August under strong water column stratification. These in-situ findings agreed well with earlier studies that corroborated Kuwait Bay as an important area where the phenomenon of reverse estuarine circulation originates in the Gulf. Thus, Kuwait Bay is a significant source of nutrients and organic matter to the Gulf Deep Water that flows into the core of the oxygen minimum zone in the northwestern Indian Ocean.

Seasonal variations of heavy metal concentrations in tissues of Talang Queenfish (Scomberoides commersonianus) from Iraqi marine and coastal waters, Northwestern Arabian Gulf

This study was carried out during the period from Winter 2010 to Winter 2011 to evaluate the concentrations of heavy metals (Fe, Co, Ni, Cu and Pb) in tissues of commercially valuable coastal fishes (Talang Queenfish, Scomberoides commersonianus) from Iraqi coastal areas around the Faw Peninsula which receives petrochemical wastes. Thus, it is important to identify the extent of concentrations of heavy metals in fish and consider potential impacts on the food chain and risks to human health. Fe had the highest level of accumulation in the four tissues examined (gill, muscle, liver and gonad) of S. commersonianus whilst Pb had the lowest (p &lt; 0.05). The order of the heavy metal concentrations in the gills, muscles, liver and gonad tissues of S. commersonianus across all the stations was Fe (198.27 μg/g) &gt; Co (21.07 μg/g) &gt; Cu (7.89 μg/g) &gt; Ni (5.43 μg/g) &gt; Pb (1.85 μg/g). This study suggests that additional measures must be taken to monitor waste and ambient water quality, and to prevent contamination of fish for human consumption

Environmental impact of a series of flash flood events on a hypersaline subtropical system in the Northwestern Arabian Gulf

A series of flash floods that swamped urban drainage systems in Kuwait in November–December 2018 drastically altered coastal hydrography. The phytoplankton responded quickly to the nutrient supply from land and reduced salinity despite elevated turbidity, as evident from rapid increases in chlorophyll a and net community production. Microphytoplankton was dominated by diatoms and the photosynthetic ciliate Myrionecta rubra. Both field observations and microcosm experiments suggested that although increased nutrient availability stimulates diatom growth, microzooplankton grazing controls their outbursts. This study revealed that in a hypersaline system similar to the northern Arabian Gulf, extreme events like flash floods have immediate but short-lived corollaries on coastal phytoplankton due to synergistic effects of bottom-up and top-down factors. The patterns are comparable to those reported from other tropical and sub-tropical systems.

Marine Geophysical Study to Explore the Seafloor Bathymetry and Geological Features at the Iraqi Corridors, Northwestern Arabian Gulf

Marine Geophysical Study to Explore the Seafloor Bathymetry and Geological Features at the Iraqi Corridors, Northwestern Arabian Gulf

Analysis of phytoplankton variations and community structure in Kuwait Bay, Northwestern Arabian Gulf

Environmental vicissitudes cause short-term variability in plankton dynamics. The effect would be more pronounced in shallow, semi-enclosed tidal coastal systems. Here, we analyzed diurnal fluctuations in coastal phytoplankton and environmental factors in relation to seasonal tidal cycles (October 2016, Fall and February–March 2017, Winter) in a sub-tropical coastal embayment (Kuwait Bay) in the northwestern Arabian Gulf. Water-column profiles were obtained for chlorophyll, photosynthetically active radiation (PAR), salinity, temperature, and dissolved oxygen. Winter was characterised by relatively cold, well‑oxygenated, nutrient-rich, and high saline waters than the fall. Nutrient levels were high during low tide and low during high tide. High-performance liquid chromatography (HPLC) analysis of phytoplankton marker pigments revealed the presence of twelve different phytoplankton functional groups. Diatoms and dinoflagellates were the most dominant groups with significant surface-bottom differences during both seasons. The phytoplankton biomass (Chl a) was the highest during the low light hours of the day with apparent day-night differences. The picoplankton community was mainly represented by the autotrophs Synechococcus (in Fall) and picoeukaryotes (in winter) with clear seasonal patterns. Compared to picoautotrophs, picoheterotrophic biomass was relatively high during winter. This study revealed that light availability and tidal mixing are the factors regulating variability in the phytoplankton community composition and biomass (Student’'s t-test, two-tailed; (P ≤ 0.1) in Kuwait Bay. High-resolution monitoring programs are essential to capture the natural variability of phytoplankton and its implication on the biogeochemistry of the shallow tide-dominated coastal systems.

Temporal trend of polychlorinated biphenyls contamination in the northwestern Arabian Gulf – Evidence from sediment records

This study provides an insight into the polychlorinated biphenyls (PCBs) inventories in the sediments of the northwestern Arabian/Persian Gulf. PCBs can be used as chemical markers that correlate with historical events in the region, to estimate the sedimentation rates in the northern Gulf, and to determine the sources of pollutants in the study area. The concentrations of PCBs were generally patchy in sediments. At Station 1 the ΣPCB concentrations generally fluctuated between 0.100 and 0.400 ng g−1 dw throughout the depositional history measured in a sediment core. There were four peaks in the ΣPCB profile corresponding to 1969, 1979, 1983 and 1991. Station 2 showed a prominent peak at depth of 25 cm. The concentrations of the ΣPCBs and ΣICE congeners at this depth were 28 and 12 ng g−1 dw respectively. Concentrations then dropped dramatically thereafter by a factor of 4. The ΣPCB concentrations at Station 3 were very low compared to the concentrations measured at Stations 1 and 2. The PCB concentration in Core 4 which was taken from open waters was 2–3 orders of magnitude lower than those in the other coastal cores. However, a 1990–91 peak was omnipresent in these cores. There is no record of PCB production within the Gulf region, and PCB releases into the Kuwait marine environment are likely to originate from their use in products. These maxima in early-1990s can be correlated to inputs from war-related activities, including the reported destruction of PCB-containing transformers and military equipment during the occupation of Kuwait. None of the recent sediment core sections at the four stations had a ΣPCB concentration near the effects range-median (ERM) concentration of 180 ng g−1, or permissible exposure limits (PEL) of 189 ng g−1, or were above the effect range-low (ERL) values of 22.7 ng g−1.

Incidental mortality events of the Indo-Pacific Finless Porpoise, Neophocaena phocaenoides in Kuwait, Northwestern Arabian Gulf

The Indo-Pacific Finless Porpoise, Neophocaena phocaenoides (G. Cuvier, 1829) is an elusive species of marine mammal under the Family Phocoenidae, inhabiting shallow coastal waters ranging from the...

New records of nudibranchs and a cephalaspid from Kuwait, northwestern Arabian Gulf (Mollusca, Heterobranchia)

In this study five new records and two probably undescribed species of heterobranch sea slugs placed in four genera, three families, and two orders are reported from Kuwait, northwestern Arabian / Persian Gulf with details and photographs. The present study increases the heterobranch diversity in Kuwaiti waters from 35 to 40 species. The range of habitats in Kuwait provides a vital opportunity for further investigation to understand the actual faunal diversity.

Depositional time trends of phosphorous accumulation in a dated sediment core from the northwestern Arabian Gulf: Can phosphorous be used to support 210Pb chronologies in coastal aquatic sediments?

The use of 210Pb dating for the reconstruction of contaminant profiles in undisturbed sediments is the most widely acceptable technique historically. Due to the uncertainties associated with the technique, dating of sediments have often been supported by ancillary evidence such as an alternative historical marker in the catchment that is preserved in the sedimentary records. The most widely used verification marker is 137Cs, which is attributed to global fallout from past nuclear weapons testing, and the Chernobyl accident. In the southern hemisphere, and the mid-latitudes, the 137Cs signal from Chernobyl fallout is often absent from the sedimentary records making it very difficult to verify the 210Pb chronologies in these natural archives. This study reports the spatial and temporal variability of total phosphorus (TP) and its forms in sediments from Kuwait Bay and provides evidence of the possibility of using Phosphorous as a potential marker to support dates derived from 210Pb dating.In the current study we report the spatial and temporal variations in the concentrations of Phosphorus from near-shore sediments from Kuwait. The mean (and range) of TP concentration in surficial sediments is 19.4 (12.2 to 24) μmol-P g−1 dry weight. The highest concentrations were measured in the deepest portions of the Bay which is characterized by fine grained sediments. The vertical profile of TP in the sediments was characterized by a gradual increase in concentration from lower layers to a subsurface maximum (at approximately 4–5 cm) followed by an exponential decrease to the sediment-water interface. The sedimentary TP profile correlated remarkably well with changes in the population of Kuwait over the last three decades, suggesting that wastewater inputs into the Bay from treatment plants are an important source of phosphorus in the coastal waters. The decrease in concentration in sediment deposited over the last five years of the core is explained by the commissioning of an improved wastewater treatment plant with higher phosphorus removal efficiency. These fluctuations preserved in the sedimentary records linked to identifiable historical events provides powerful evidence that this nutrient associated with wastewater inputs in coastal aquatic environments can be used as ancillary information to support 210Pb dating.

Temporal variations in abundance and species richness of phytoplankton with emphasis on diatoms in the subtidal waters of Umm Al-Namil Island, north-western Arabian Gulf of the ROPME Sea Area

Aim: The present study aimed to understand the physico-chemical factors affecting the abundance and species richness of phytoplankton communities, with emphasis on diatoms at the end of the intertidal zone and start of subtidal zone. Methodology: Water quality and phytoplankton community species richness and abundance were measured in the subtidal waters of Umm Al-Namil Island, Kuwait Bay. Kruskal-Wallis statistical approach was used to measure the effect of various environmental parameters on abundance and species richness as well as abundance-species richness relationships using R statistical software. Results: The physico-chemical parameters showed variations at each sampling event as well as within the same season. Total phytoplankton mean abundance values in summer (22.26 ± 0.66 ind. 5l-1) and winter (21.63 ± 0.52 ind. 5l-1) did not significantly vary and the lowest mean abundance was observed during spring (26.36 ± 0.33 ind. 5l-1). Species abundance showed clear pattern with the events, resulting in somehow a negative relationship. Mean species richness was highest during autumn (24.59 ± 1.51), while no significant difference was observed between spring (11.09 ± 0.33), winter (10.47 ± 0.51) and summer (10.11 ± 0.66). The results indicate that phytoplankton species richness and species abundance in Umm Al-Namil Island varied temporally in response to fluctuations in environmental conditions. Interpretation: The end of intertidal zone and beginning of subtidal zone is affluent in diverse forms of phytoplankton species, specifically diatoms since Kuwait Bay is a eutrophic area mainly due to sewage and urbanization. Therefore, a temporal monitoring is required in order to observe any changes in either physico-chemical or biological factors with time and that will help in future conservation and restoration programs. Conservation approaches should be considered seriously since some diatoms like Melosira moniliformis, Gyrosigma diminutum, Fragilaria martyi, Hemidiscus cuneiformis, Planktoniella sol and Amphiprora plicata have been observed only at one event despite abundance and season.