Gulf Of Aqaba Research Articles

Case report: tracking data from foraging hawksbill turtles in the northern Red Sea

BackgroundHawksbill turtles (Eretmochelys imbricata) are Critically Endangered throughout their global range, and concerningly little is known about this species in the Red Sea. With large-scale coastal development projects underway in the northern Red Sea, it is critical to understand the movement and habitat use patterns of hawksbill turtles in this environmentally unique region, so that effective conservation strategies can be implemented. We satellite tagged three hawksbill turtles, one 63 cm curved carapace length adult male captured near Wahlei Island, one 55 cm turtle captured in the Gulf of Aqaba, and one 56 cm turtle suffering from a floating syndrome which was captured at Waqqadi Island, rehabilitated, and released at Waqqadi Island. Turtles were tracked for 156, 199, and 372 days between October 2020 and November 2021.ResultsWe calculated the home ranges and core use areas of hawksbill turtles using kernel-density estimations and found that each turtle showed high fidelity to their foraging sites. Home ranges calculated with GPS-derived locations ranged between 13.6 and 2.86 km2, whereas home ranges calculated with Argos-derived locations ranged from 38.98 to 286.45 km2. GPS-derived locations also revealed a higher proportion of time spent in coral and rock habitats compared to Argos, based on location overlap with the Allen Coral Reef Atlas. We also found that turtles were making shallow dives, usually remaining between 0 and 5 m.ConclusionsWhile the number of tracked turtles in this study was small, it represents an important contribution to the current understanding of spatial ecology among foraging hawksbill turtles globally, and provides the first-ever reported hawksbill turtle tracking data from the Red Sea. Our results suggest that protecting coral reef habitats and implementing boating speed limits near reefs could be effective conservation measures for foraging hawksbill turtles in the face of rapid coastal development.

Higher Nighttime Rates of CaCO3 Dissolution in the Nature Reserve Reef, Eilat, Israel in 2015–2016 Compared to 2000–2002

AbstractThe current study (2015–2016) evaluated changes in the net community calcification (NCC) and maximum nighttime CaCO3 dissolution (Dmax) in the Nature Reserve Reef (NRR), northern Gulf of Eilat (GOE), and northern Red Sea, compared to measurements made at the same site during 2000–2002. The NCC and Dmax were calculated as a function of the reef‐water residence time, the difference between the open‐sea total alkalinity (TA) and its reef‐water daily average (for NCC), and its nighttime maximum (for Dmax). The average NCC was 50 ± 13 and 68 ± 22 mmol C m−2 day−1 in 2000–2002 and 2015–2016, respectively. This change is consistent with the live coral cover increase in the NRR during this period, following the final removal of fish cages from the northern GOE in 2008. In contrast, wintertime Dmax values in 2015–2016 were five times higher on average compared to 2000–2002. We hypothesize that these higher rates could be the result of increased boring organism activity and sedimentary organic content, which developed throughout the fish farming period and are maintained by the naturally occurring seasonal eutrophication in the northern GOE. Where, in general, Dmax was higher during the winters, when nighttime reef water aragonite saturation (Ωarag) was lower, while open water chlorophyll a and nitrate were higher, compared to summertime. Thus, it is possible that the combination of seasonal eutrophication and ocean acidification (OA) in the GOE and possibly other coral reef sites around the world, may shift coral reefs to net dissolution even sooner than previously predicted from OA alone.

Controls on carbonate-siliciclastic relationships in quaternary deposits of the Midyan coast of the Gulf of Aqaba, Saudi Arabia

Quaternary deposits of the Midyan coast of Saudi Arabia include coral-bearing limestones interbedded with sheet-flow siliciclastic sands and gravels, interpreted as braid-delta fan deposits. The limestones and their contained faunas provide evidence of periodic local stabilization of gravel surfaces and effective starvation of siliciclastic supply. Some indicate growth and deposition in waters a metre or so deep whereas others were substantially deeper. An additional group reflects initial deposition in shallow waters with resedimentation downslope by storm or other ‘delta-front’ processes. The surfaces of the fans provided morphological and environmental analogues to fore- and back-reef situations in which corals, calcareous coralline algae, molluscs, and echinoderms flourished, but in this area did not form independent reefs. The dominant controls on the changes from siliciclastic- to carbonate-dominated deposition were not transitional, and primarily related to channel and fan-lobe migration rather than tectonic or eustatic sea level changes. Similar variations in the distribution of siliciclastic sediments may control carbonate occurrence in other mixed sequences.

Identifying an Evaporative Thermal Refugium for the Preservation of Coral Reefs in a Warming World—The Gulf of Eilat (Aqaba)

AbstractCoral bleaching events are more frequent and severe as global temperatures rise. However, analysis of the surface energy fluxes that substantially affect the thermoregulation of shallow reef environments is rare. Previous work on evaporative cooling in a humid reef environment led to the hypothesis that in proximity to desert regions, drier air enhances evaporative cooling of water overlying coral reefs, reducing the risk of extreme high‐water temperatures. Eddy Covariance measurements made over a shallow desert fringing coral reef in the Gulf of Eilat (Israel) during summer measured evaporation of 10.3 mm d−1 which is maintaining water temperature much lower than the overlying air temperature. In addition, measurements of the most severe marine heatwave that was ever documented in the region are presented as a case study for future reference to the processes that lead to and proceed a marine heatwave, which is induced by synoptic scale events that cause a ∼50% reduction in evaporation rate. Results are compared to similar measurements from a tropical coral reef, where a lower evaporation rate suppressed by higher humidity is unable to offset the heating of water overlying the reef. We conclude that evaporative cooling is a key mechanism protecting coral reefs located in deserts from extreme high‐water temperatures, thereby representing possible thermal refugium for corals against background global warming.

The cusk eel Ophidion smithi (Ophidiiformes: Ophidiidae): new data and northernmost record from the Gulf of Aqaba

Das Bartmännchen Ophidion smithi (Fowler, 1934) wird beschrieben auf Grundlage eines Exemplares, das bei Eilat, Israel im Golf von Akaba, Rotes Meer, gesammelt wurde. Hiermit wird ein früherer Fund aus dem Roten Meer (und dem Golf von Akaba) ohne genaue Fundortangabe bestätigt. Letzterer ist zugleich der erste Fund dieser Art aus Israel sowie der nördlichste Fund dieser Art.

Non-native species in the north Gulf of Aqaba (Red Sea) revealed from environmental DNA

The movement of organisms facilitated by anthropogenic activities is a serious threat to marine diversity, especially for endemic species that may be outcompeted from non-indigenous species (NIS). In this study, we have analyzed communities inhabiting the north of the Gulf of Aqaba, Red Sea, employing environmental DNA (eDNA) metabarcoding. That gulf is especially rich in species and population endemism. We have detected NIS representing 36% of the total number of species found from eDNA. Primary producers were more abundant in the NIS than in the native fraction of species, suggesting that functional diversity could be altered if NIS thrive there. We discuss maritime traffic as a factor that may enhance the introduction of non-natives in this region and emphasize the importance of the control of these species that may threaten the rich endemic biota of the Red Sea.

Long-Term Loss of Coral Reef in the Gulf of Aqaba Estimated from Historical Aerial Images

Located at the northern tip of the Red Sea, the Gulf of Aqaba coral reef is highly susceptible to anthropogenic pressure associated with the massive development of the two neighboring cities of Eilat and Aqaba. Over the years, the reef has been extensively studied in a number of research and monitoring programs, which provide detailed information on a variety of ecological, physiological, biogeochemical and physical variables. Due to the local nature of these surveys, although the state of the reef at specific times and locations is very well characterized, long-term changes in the spatial characteristics of the reef as a whole have not yet been quantified. Here, through analysis of historical aerial images, we address one of the most important aspects of this knowledge gap and quantify the decrease in coral reef coverage, with respect to a baseline level prior to the establishment of the City of Eilat in 1949. Our results show that along a 8460 m segment of the shoreline at the northwestern edge of the GOA (29°29′–30°N/34°54′–35°E), infrastructure construction has led to the loss of more than 4810 m2 of coral reef. This loss has been caused either directly by the construction (most importantly the Eilat Port) or indirectly by changing environmental conditions, which in turn damage the reef. Our results show that historical aerial images can provide a unique source of information on the spatial characteristics of marine and coastal systems prior to the era of Earth observation satellites.

Initiating a DNA Barcoding Reference Library of Stony Corals from the Gulf of Eilat (Red Sea)

Accurate identification of scleractinian coral species is fundamental for proper biodiversity estimates, for aiding in efforts of reef monitoring, conservation, restoration, and for the management of coral reefs. Here, we provide the first DNA barcoding reference library for coral species in Eilat, Red Sea, based on the mitochondrial gene cytochrome c oxidase subunit I (COI), targeting the identification of stony coral species from shallow (0–12 m) reefs. A total of 191 specimens were collected, depicting 14 families, 39 genera, and 94 species (all are new full species records to the BOLD system). Three species (Sclerophyllia margariticola, Cyphastrea magna, and Psammocora profundacella) are first records for Eilat’s coral reef. The results presented here strengthen the claim that COI is not universally informative for delimitation of stony coral species, a notion reinforced by the constructed maximum likelihood phylogenetic tree. This library is the first step in a long journey towards elucidating coral biodiversity in the coral reef at Eilat and for improving future management and monitoring efforts.

Octocorals in the Gulf of Aqaba exhibit high photosymbiont fidelity.

Symbiotic associations, widespread in terrestrial and marine ecosystems, are of considerable ecological importance. Many tropical coral species are holobionts, formed by the obligate association between a cnidarian host and endosymbiotic dinoflagellates of the family Symbiodiniaceae. The latter are abundant on coral reefs from very shallow water down to the upper mesophotic zone (30-70 m). The research on scleractinians has revealed that the photosymbiont lineages present in the cnidarian host play an important role in the coral's ability to thrive under different environmental conditions, such as light regime and temperature. However, little is known regarding octocoral photosymbionts, and in particular regarding those found deeper than 30 m. Here, we used ribosomal (ITS2) and chloroplast (23S) markers to uncover, for the first time, the dominant Symbiodiniaceae taxa present in 19 mesophotic octocoral species (30-70 m depth) from the Gulf of Aqaba/Eilat (northern Red Sea). In addition, using high-throughput sequencing of the ITS2 region we characterized both the dominant and the rare Symbiodiniaceae lineages found in several species across depth. The phylogenetic analyses of both markers were in agreement and revealed that most of the studied mesophotic octocorals host the genus Cladocopium. Litophyton spp. and Klyxum utinomii were exceptions, as they harbored Symbiodinium and Durusdinium photosymbionts, respectively. While the dominant algal lineage of each coral species did not vary across depth, the endosymbiont community structure significantly differed between host species, as well as between different depths for some host species. The findings from this study contribute to the growing global-catalogue of Cnidaria-Symbiodiniaceae associations. Unravelling the Symbiodiniaceae composition in octocoral holobionts across environmental gradients, depth in particular, may enable a better understanding of how specialized those associations are, and to what extent coral holobionts are able to modify their photosymbionts.

Contrasting genetic diversity and structure between endemic and widespread damselfishes are related to differing adaptive strategies

AbstractAimSeveral marine biogeographical provinces meet at the Arabian Peninsula. Where and how these junctions affect species is poorly understood. We herein aimed to identify the barriers to dispersal and how these shape fish populations, leading to differing biogeographies despite shared habitat and co‐ancestry.TaxonDascyllus marginatus (endemic) and Dascyllus abudafur (widespread).LocationCoral reefs from the Red Sea (RS), Djibouti, Yemen, Oman, and Madagascar.MethodsWe tested potential barriers to gene flow using RADseq‐derived SNPs and identified whether population genetic differences on each side of these barriers were neutral or selective to relate this to the biogeography of the species. Seven locations (ranging over 5100 km) were sampled for the endemic and six (ranging over 7400 km) for the widespread species, taking 20 individuals per location, with two exceptions.ResultsDascyllus marginatus populations (comprising 5648 SNPs) had an order of magnitude higher genetic differentiation compared to D. abudafur (comprising 10,667 SNPs), as well as several outlier loci that were absent in D. abudafur despite equal sampling locations. In both species, the RS and Djibouti specimens formed one genetic cluster separated from all other locations. Although ranging from the RS to Madagascar, D. abudafur was absent in Yemen and Oman.Main ConclusionsStronger genetic structure at smaller geographical scales and outlier loci in the endemic species seem associated with faster adaptation to environmental differences and selective pressure. Genetic differentiation in the widespread species is neutral and only occurs at large geographical distances. Restrictive transitions (between the Gulf of Aqaba and the RS or the RS and the Gulf of Aden) do not hinder gene flow in either species, and the environmental shift within the RS (at 22°N/20°N) only affected the endemic species. The genetic break in the Gulf of Aden likely reflects historical colonization processes and not contemporary environmental regimes.

Observations of the First Documented Indian Ocean Humpback Dolphin (Sousa plumbea) in the Northernmost Red Sea Gulf of Aqaba

Observations of the First Documented Indian Ocean Humpback Dolphin (Sousa plumbea) in the Northernmost Red Sea Gulf of Aqaba

Two-year seasonality (2017, 2018), export and long-term changes in coccolithophore communities in the subtropical ecosystem of the Gulf of Aqaba, Red Sea

A two-year (2017, 2018) study of coccolithophores was undertaken in the Gulf of Aqaba in the northern Red Sea to 1) determine the local diversity and community succession patterns with high temporal and taxonomic resolution, 2) determine the contribution to exported inorganic carbon and 3) evaluate changes in communities relative to those in the mid-1970's reported in Winter et al. (1979). As typical, the oceanographic conditions in the Gulf alternated between stratified, oligotrophic through spring/summer, and mesotrophic during winter due to deep convective mixing. Noticeably, the second summer of 2018 was warmer resulting in a more pronounced thermocline. Overall, the coccolithophore dynamics followed the seasonal changes in oceanographic conditions. During the mixing period, coccolithophores were denser (>25 coccospheres mL−1) and were estimated to account on average for 3.46% of the total Chl-a. The communities were fairly homogeneous through depths and over time with a marked dominance of Emiliania huxleyi and Gephyrocapsa ericsonii. During the stratified season, coccolithophore densities were lower, particularly at the surface, such that coccolithophores were estimated to represent on average 0.72% of the total Chl-a. However, the diversity was higher and a clear vertical zonation developed with well-defined upper, intermediate and deep-dwelling communities. These included Umbellosphaera spp., Rhabdosphaera clavigera, a variety of Syracosphaera spp., holococcolithophores and Florisphaera profunda, respectively, as typical in oligotrophic systems. This further underscores the pelagic nature of the Gulf of Aqaba. Noticeably, however, coccolithophores declined in abundances and diversity during 2018, possibly due to the warmer conditions. The relative export of inorganic carbon by coccolithophores largely correlated with the density of living communities, representing <4% and <10% of total inorganic carbon exports during the stratified and mixing periods, respectively. A marked differentiation between different coccolithophore life phases was also detected. Broadly, holococcolithophores inhabited preferentially shallow, oligotrophic water layers in the stratified season, while heterococcolithophores prevailed in deeper water layers or in winter. Yet, species-specific deviations to this pattern were also detected. Finally, comparisons with the 1970's revealed marked changes compared to current communities. G. ericsonii appeared less prevalent and Umbellosphaera spp. displayed a wider temporal residence through spring/summer. Moreover, F. profunda and other deep dwelling species absent in the past are now common during the peak of summer. These observations are indicative of changes in local microbial communities, possibly linked to the ongoing rise in sea temperatures. This study provides a detailed baseline information on coccolithophores for future reassessments of community changes in the GoA.

Multiscale geoelectrical characteristics of seawater intrusion along the eastern coast of the Gulf of Aqaba, Jordan

Jordan's eastern coast of the Aqaba gulf is an example of seawater intrusion in extremely arid conditions and escalating urban development. The presented research is the first to use a large dataset of ground–based transient electromagnetic, which consists of 160 TEM soundings of various loop dimensions (100 m × 100 m, 50 m × 50 m, and 25 m × 25 m) that were conducted in a quasi–grid layout (35 km2 surveyed area), and also with dense TEM sites combined along three ERT profiles. To obtain valid and reliable resistivity interpretation, geological and hydrogeological analyses of existing boreholes were used in the interpretation of multiscale dimensions of geophysical data, such as 1D–quasi 3D–inversion of TEM data and 2D inversion of ERT data.1D TEM resistivity models (at depths ranging from 40 to 360 m) show potential seawater intrusion of several kilometers from the gulf of Aqaba into a terrestrial unconfined sandy aquifer of resistivity <3 Ω·m. A resistivity >3 Ω·m and <70 Ω·m, on the other hand, best describes brackish seawater–bearing sediments with a wide range of total dissolved solids (1400–7000 mg/l). Resistivity models suggest upwelling along faults where the deep terrestrial semi–confined Kurnub sandstone aquifer is uplifted and salinized from direct seawater intrusion and/or sub–Cretaceous aquifers. The combined interpretation of resistivity models along profiles (ERT and TEM data) near coast areas demonstrated that the clastic sequence is a heterogeneous medium at the survey scale, with saline water–bearing (0.6–1 Ω·m) sediments having a very sharp interface with brackish water–bearing (10–30 Ω·m) sediments. Several geoelectrical signatures appear in the intrusion zone as an irregular pattern like alluvial sediments thickening and abrupt lateral resistivity changes. These patterns have been associated to lithological or structural control factors, which allowed the explanation of seawater intrusion characteristics.

Landscapes of Mobility and Movement in North-West Arabia: A Remote Sensing Study of the Neom Impact Zone

The historic environment of north-west Saudi Arabia is likely to be severely impacted by the construction of the Neom mega-city complex and the development of the city’s hinterland. This region, located east of the Gulf of Aqaba, has only been subject to limited archaeological survey in the past, limiting any assessment of this negative impact. This paper presents data collected through a remote sensing survey of the region undertaken by the Endangered Archaeology in the Middle East and North Africa (EAMENA) project, independent of the Neom project. It is argued that this data reflects a landscape of movement between north and south, with evidence of structures and monuments from at least the Bronze Age through to the pre-Islamic period, but little evidence of permanent settlement or agriculture. This should not be dismissed as a peripheral landscape, but one that contains rich archaeological evidence of concentrated activity, suggesting that some areas have held long-term significance to the people inhabiting and moving through this region.

Integrated approach of remote sensing and machine learning to simulate and predict petroleum pollution and algal blooms along Aqaba Gulf

To simulate and predict the appropriate indices for algal blooms and petroleum pollution, this study combined remote sensing data and models of Machine Learning ML for the Aqaba Gulf’s condition. For algal blooms indication; floating algal index (FAI) was selected as the best index with 0.937 and for petroleum indices; ratio index (RI) was selected with 0.984. The collected data within the number of samples were separated into two parts: 80% for calibration to train and adjust the back propagation in neural network BPNN and partial least squares regression PLSR, and 20% for the external validation. Therefore, and based on the RI data, FAI was predicted using MLP, the obtained results showed that the ML algorithms gave models with high quality performance with R2= 0.955 and RMSE = 10.90. The PLSR and multilayer perceptron (MLP) were used to predict petroleum pollution using the extracted values to bands. The results showed that both models were obtained excellent models for predicting petroleum pollution. In general, MLP outperforms PLSR; within R²=0.941. Accordingly, the ML model was able to estimate the algal blooms and petroleum contamination with good accuracy. In the validation process, the determination coefficient R2 was 0.84 with an average square error equal to 0.076. As demonstrated, MLP could be a powerful mathematical tool for environmental analysis and prediction. The integration of remote sensing indices and data-driven statistical modeling were highly recommended for further similar studies.

Tritium and radiocarbon in the water column of the Red Sea

Despite being the busiest transient sea in the world due to the Suez Canal, radionuclide distribution studies in seawater and sediment of the Red Sea remain rare. A sampling expedition in the Red Sea was conducted from June 9 to July 6, 2021, visiting a transect of several deep sampling stations located along the central axis of the basin from the Gulf of Aqaba to the southern Red Sea (near Farasan Island, Saudi Arabia). The collected seawater profile samples were analyzed for tritium, radiocarbon and oxygen-18. The observed tritium levels in surface waters of the Red Sea peaked at 0.3–0.4 TU, similar to the values observed in the western Arabian Sea (decay corrected). The values observed at waters below 150 m were around 0.2 TU, however, at depths of 450 and 750 m, tritium minima (<0.2 TU) were observed, which could be associated with a partial return flow of bottom waters from the southern to the northern Red Sea. At two stations at the depth of about 550 m, deep Δ14C minima were observed as well (−4‰ and −10‰), documenting ongoing transport of carbon in the water column, important for sink of anthropogenic carbon.

Ecological insights into the resilience of marine plastisphere throughout a storm disturbance

Among numerous research about marine plastisphere, the community living on the surface of plastic debris, little attention was given to the ecological mechanisms governing prokaryotes compared to eukaryotes, and even less focused on their resilience in a changing climate with more storm prevalence. Our current research recruited an integrated approach involving community succession across temporal dimension, ecological mechanisms that govern the assembly, and resilience to environmental perturbations to highlight the ecology of different kingdoms in the plastisphere. Towards this goal, we examined the succession of the prokaryotic and eukaryotic communities on artificial plastic nets in a sidestream of seawater from the Gulf of Aqaba over 35 days. A robust local storm enabled investigation of the alterations before, during, and after this disturbance, aiming at the community's potential to recover. Data from 16S and 18S rRNA sequencing and microscopic analyses decrypted the plastisphere diversity, community assembly, and stochasticity, followed by further analyses of functional and co-occurrence networks for the prokaryotic group. Prokaryotic and eukaryotic communities underwent exact opposite ecological mechanisms. While determinism driven by a robust environmental selection dictated the prokaryotic community assembly, stochasticity prevailed when this condition was relaxed. Interestingly, resilience against disturbance was observed in prokaryotes but not in eukaryotes. The decrease in compositional, functional diversity and network complexity in the prokaryotic community was reversed, presumably due to the niche specification process and high dispersal. Niche specification following perturbation was evident in some bacteria by selected functions associated with plastic degradation, stress response, and antibiotic resistance. On the contrary, eukaryotes decreased in diversity and were dominated by the commonly found Chlorophyta towards the later successional period. Novel findings on the ecology of marine plastisphere during perturbation encourage the integration of this aspect into prediction research.

Trapezia Crabs That Dwell in Distinctive Day/Night Canopy Compartments of a Marine Animal Forest, Forage on Demersal Plankton

Canopies of branching corals harbor a wide range of sessile- and mobile-dwelling species that benefit from the physical compartments and the micro-environments created by the complex three-dimensional structures. Although different compartments within canopies are differentially used by inhabitant species, the distribution of mobile animals between coral canopy compartments are not fully explored. Here, we study Stylophora pistillata, a common branching coral in the Gulf of Eilat that harbors obligatory crabs from the family Trapezia. Two in situ surveys elucidated diel dynamics in compartmental distributions of Trapezia species within S. pistillata canopies compartments, associated with the crab’s body size and day/night activities. Whereas all crabs were found within sheltered spaces in the coral canopy understory or in the base during day hours, laboratory experiments revealed that nighttime distributions of small and large crabs (in middle and up compartments, respectively) are not intraspecific competition-borne, but rather, the outcome of preferred crab-size location for a novel feeding type, predation on demersal plankton. This study, thus, disclosed the importance of studying the coral’s three-dimensional structures and within canopies’ compartments for understanding the biology of dwelling species in the animal forests’ canopies.

Extreme heat loss in the Northern Red Sea and associated atmospheric forcing

A regional, high-resolution reanalysis was analyzed to explore extreme heat loss events in the Northern Red Sea (NRS) and their links to specific regional atmospheric circulation patterns. Such events are determinant for the overturning circulation of the Red Sea and occur frequently between November and March, with maximum frequency during December and January. During these events, the most intense heat loss, often with daily-averaged values lower than -1000 W/m2, is found over the southern half of the Gulf of Aqaba and along the western coastline of the open NRS. Analyses of the spatial modes of variability of these events suggest that the majority of them extend over the entire NRS in an almost uniform way; however, secondary, nonuniform patterns related to regional adjustment in the wind field are also identified. The uniform cold outbursts are associated with distinct atmospheric circulation patterns, which favor the transfer of cold air masses from higher latitudes over the eastern Mediterranean Seaviaa strong northwest wind field. Nonuniform events affect considerable parts of the NRS and occur when cold and dry air masses reach the NRS through the Middle East and the northern part of the Arabian Peninsula. The regional sea level pressure drives a clockwise rotation of the wind field that ultimately blows from the northeast/east direction. This rotation of the wind field favors local intensification and lee areas defined by the complex topography and characteristic gaps in the mountain chain along the eastern coastline of the NRS, reflecting the differentiations in the spatial distribution of the heat flux minima.

Tropical storm-induced disturbance of deep-water porewater profiles, Gulf of Aqaba

Storms have long been recognized as a force that agitates sediments, even in the deep-water. In shallow water depths (<40 m) sediments are affected dominantly by wave actions, while in deeper-water (>100 m) the impact is primarily due to suspended sediment flow. While such transport events have been studied sedimentologically extensively, their impact on porewater chemistry is yet poorly understood. The March 2020 tropical storm which impacted the Gulf of Aqaba (GoA) offered a unique opportunity to investigate this particular topic. Detailed sedimentological, mineralogical and porewater analyses were carried out on two sets of short cores collected along a transect from 270 m to 700 m water depths before and after the storm on the western margins of the GoA, which represents a steep slope with a potential for high energy transport events. The cores exhibited a decrease in grain size in the mid-slope water depth and an increase at the base of the slope after the storm, with the top of the core being enriched with terrestrial material. Both Fe2+ and NOx profiles exhibited a marked shift in the aftermath of the storm. NOx concentrations increased in the top 5 cm of all the cores and the ferruginous zone migrated upwards in both the top and bottom of the slope. We postulate that the storm event remixed the top of the sediment column and infused it with fine material. This filled burrows and decreased the diffusive coefficient across the sediment-water interface, limiting the exchange of ions. As a result, the porewater trapped in the sediment has developed along the terminal electron acceptor chain.