Southern Red Sea Research Articles

Isotopic composition of Conomurex fasciatus shells as an environmental proxy for the Red Sea

Abstract The marine gastropod Conomurex fasciatus (Born 1778) is the main component of thousands of shell middens on the Farasan Islands in the southern Red Sea. The middens date from 6500 to 4500 cal BP and cover the period of increased aridification over the region. No general research on C. fasciatus has been carried out before and basic information about the species is mostly speculative. To test if C. fasciatus shells can be used as a recorder of climate variability, we collected living specimens from the Farasan Islands, in Saudi Arabia, over a 1.5 year period. This area receives almost no precipitation and sea surface salinity is extremely high (38–39 psu), and sea surface temperature (SST) ranges from +26.5 °C to +34.9 °C. Raman spectroscopy results on modern C. fasciatus shell samples show these specimens to be aragonitic. Ground fragments from archaeological C. fasciatus shells used for isotope analyses were also measured by Raman spectroscopy and shown to be well preserved against diagenetic alterations leading to aragonite to calcite transformation. Measured shell-edge δ18O values range from −0.5‰ to −1.7‰. Calculated modern shell edge temperatures from these δ18O values correlate with modern SST measured on site with an error of ±2.4 °C. Two different growth rates occurred in the shells of C. fasciatus. The measurement of growth increments in the lip part of adult specimens indicates a tide-related growth rate of ∼13 mm/year. Sequential δ18O data from juvenile parts of the shell indicates a faster growth rate of ∼90 mm/year. This growth rate and the correlation of δ18O with measured temperatures allows the use of C. fasciatus shell δ18O as a palaeoclimate proxy.

Red Sea isolation history suggested by Plio-Pleistocene seismic reflection sequences

High evaporation rates in the desert climate of the Red Sea ensure that, during glacial sea level lowstands when water exchange with the Indian Ocean was more restricted, water salinity and δ18O became unusually extreme. Modeling of the effect on Red Sea sedimentary δ18O has been used previously to reconstruct relative sea level to 500 ka and now poses the question of whether that sea-level model could be extended if continuous core material of older sediment became available. We attempt to address this question here by examining seismic reflection data. The upper Pleistocene hemipelagic sediments in the Red Sea contain intervals of inorganic aragonite precipitated during supersaturated conditions of sea-level lowstands. Seismic impedance changes associated with boundaries to those aragonite-rich layers appear to explain seismic reflection sequences. A segment of Chirp sediment profiler data from the central Red Sea reveals prominent reflections at ∼1, ∼5, ∼23, ∼26 and ∼36 ms two-way travel time (TWT) from the seabed. Based on depths to the glacial marine isotope stages (MIS) in cores, we relate the upper three reflections to the tops of aragonite-rich layers and hence the sea level rises immediately following MIS 2, 6 and 12. The reflection at 26 ms is related to an unusually rapid fall into MIS 12 predicted by one sea level reconstruction, which may have created an abrupt lower boundary to the MIS 12 aragonite-rich layer. With the aid of seismogram modeling, we tentatively associate the ∼36 ms reflection with the top of an aragonite-rich layer formed during MIS 16. Furthermore, some segments of lower frequency (airgun and sparker) seismic data from the central and southern Red Sea show a lower (earlier) Plio-Pleistocene (PP) interval that is less reflective than the upper (late) PP interval. This implies less variability in sediment impedance and that extreme variability in water salinity did not develop; water exchange with the Indian Ocean likely continued throughout this interval. These results suggest that viable relative sea level reconstructions may be recovered from Red Sea sediment δ18O data to at least MIS 16 and perhaps even as far back as the early Pliocene.

Deformation of a young salt giant: regional topography of the Red Sea Miocene evaporites

AbstractThe deformational behaviour of ‘salt giants’ during and shortly after their deposition is difficult to decipher in ocean margin settings where the original evaporites have been deeply buried and strongly mobilized. Here, we examine seismic reflection data from the Red Sea, where evaporites deposited until the end of the Miocene (~5.3 Ma), are generally covered by only 200–300 m of low‐density sediments and where the presence of an axial spreading centre allows us to observe how they have responded to a varied configuration of underlying basement. The regional morphology of the S‐reflection, representing the evaporite surface, is mapped out from seismic data from 13 cruises. The S‐reflection is locally rugged and commonly angular. It is either underlain by layered reflectivity, suggestive of layered evaporite beds, or by more transparent seismic character, suggestive of massive halite. On average, the depth of the reflection on the flanks of the axial rift systematically declines from 700 to 1100 m below sea level (mbsl) going northwards from 16 to 23°N. In the central Red Sea, the S‐reflection has 100‐ to 200‐m‐deep depressions, extending towards the coasts in places. In the southern Red Sea, the S‐reflection forms a surface at 300–800 mbsl that appears less disrupted. We suggest that the evaporites originally had a flat, horizontal surface at the end of the Miocene and have subsequently been distorted by isostatic effects and axial rifting, which in turn promoted evaporite flowage. Off‐axis evaporite depressions correspond with flows identified with multibeam sonar. Furthermore, across‐rift lows in Bouguer gravity anomalies represent valleys in the underlying basement. The off‐axis evaporite depressions overlie those valleys, as would be expected if halokinetic movements were greatest where the evaporites are locally thick, leading to deflation of the evaporite surface. The thickness of post‐Miocene sediment, also mapped out as part of this procedure, confirms the generally pelagic nature of this interval and increases on average from ~250 to 300 m from the central to the southern Red Sea, mimicking the variation in pelagic productivity observed in the present water column.

Formation and spreading of Red Sea Outflow Water in the Red Sea

AbstractHydrographic data, chlorofluorocarbon‐12 (CFC‐12) and sulfur hexafluoride (SF6) measurements collected in March 2010 and September–October 2011 in the Red Sea, as well as an idealized numerical experiment are used to study the formation and spreading of Red Sea Outflow Water (RSOW) in the Red Sea. Analysis of inert tracers, potential vorticity distributions, and model results confirm that RSOW is formed through mixed‐layer deepening caused by sea surface buoyancy loss in winter in the northern Red Sea and reveal more details on RSOW spreading rates, pathways, and vertical structure. The southward spreading of RSOW after its formation is identified as a layer with minimum potential vorticity and maximum CFC‐12 and SF6. Ventilation ages of seawater within the RSOW layer, calculated from the partial pressure of SF6 (pSF6), range from 2 years in the northern Red Sea to 15 years at 17°N. The distribution of the tracer ages is in agreement with the model circulation field which shows a rapid transport of RSOW from its formation region to the southern Red Sea where there are longer circulation pathways and hence longer residence time due to basin wide eddies. The mean residence time of RSOW within the Red Sea estimated from the pSF6 age is 4.7 years. This time scale is very close to the mean transit time (4.8 years) for particles from the RSOW formation region to reach the exit at the Strait of Bab el Mandeb in the numerical experiment.

Combining multivariate analysis and human risk indices for assessing heavy metal contents in muscle tissues of commercially fish from Southern Red Sea, Saudi Arabia.

Jizan fishers are the major fish source for more than 1.5 million populations in the southern region in Saudi Arabia. Despite the overgrowing of various man-made activities in Jizan City, no recent study on environmental monitoring was reported. In the current study, heavy metals were quantified in muscle tissues of 12 fish species, as the most edible, from Jizan fisheries. Electrothermal atomic absorption spectrophotometry was used for quantification after microwave wet digestion. Acceptable recovery values (83.46-97.48%) for spiked fish samples with standard solutions were obtained. The following wide ranges of heavy metal concentrations (μg/g, wet weight) in studied fish species were recorded: V (0.004-0.561), Cr (0.013-0.477), Mn (0.073-0.128), As (0.002-0.935), Se (0.083-3.058), Sn (2.835-5.540), and Pb (0.150-0.386). Comparing with international permissible limits, lower levels were recorded in the current study. For total metal accumulation, the relationship between species was examined by cluster analysis, which showed that Epinephelinae was the farthest species from others. The principal component analysis shows one component indicating normal distribution of heavy metals in fish species. Different metal pollution indices (1.35-0.30), which shows the distribution of the total heavy metal concentrations in each species, were recorded. The hazard indices for muscle consumption were less than 1.0 for all studied metals at both ingestion rates except Sn which showed a marginal value of 28.9.

Exploring seascape genetics and kinship in the reef sponge Stylissa carteri in the Red Sea.

A main goal of population geneticists is to study patterns of gene flow to gain a better understanding of the population structure in a given organism. To date most efforts have been focused on studying gene flow at either broad scales to identify barriers to gene flow and isolation by distance or at fine spatial scales in order to gain inferences regarding reproduction and local dispersal. Few studies have measured connectivity at multiple spatial scales and have utilized novel tools to test the influence of both environment and geography on shaping gene flow in an organism. Here a seascape genetics approach was used to gain insight regarding geographic and ecological barriers to gene flow of a common reef sponge, Stylissa carteri in the Red Sea. Furthermore, a small-scale (<1 km) analysis was also conducted to infer reproductive potential in this organism. At the broad scale, we found that sponge connectivity is not structured by geography alone, but rather, genetic isolation in the southern Red Sea correlates strongly with environmental heterogeneity. At the scale of a 50-m transect, spatial autocorrelation analyses and estimates of full-siblings revealed that there is no deviation from random mating. However, at slightly larger scales (100–200 m) encompassing multiple transects at a given site, a greater proportion of full-siblings was found within sites versus among sites in a given location suggesting that mating and/or dispersal are constrained to some extent at this spatial scale. This study adds to the growing body of literature suggesting that environmental and ecological variables play a major role in the genetic structure of marine invertebrate populations.

Lithologic units and stratigraphy of the Farasan Islands, Southern Red Sea

The geology of the Farasan Islands was studied using an integration of field investigation, Paleontological analysis, reinterpretation, and regional correlation of existing wells data. This investigation indicated that the sedimentary and stratigraphic succession in the islands consists of five major units: (1) sand, (2) coral reef limestone, (3) marly limestone, (4) shale, and (5) evaporite. Paleontological analysis of surface and subsurface shale samples indicated a Miocene age. In the subsurface, a thick evaporate succession underlies the area extending to 668 m depth. None of the boreholes in the islands have penetrated the basement. Between the Farasan limestone of Pleistocene and Pliocene age and the underlying evaporite succession, it is evident in boreholes data that there is shale unit with varying thickness and interbedded gypsum levels. Regional correlation of available wells data suggests that similar sedimentary and stratigraphy succession ably to the region.

Birth of two volcanic islands in the southern Red Sea.

Submarine eruptions that lead to the formation of new volcanic islands are rare and far from being fully understood; only a few such eruptions have been witnessed since Surtsey Island emerged to the south of Iceland in the 1960s. Here we report on two new volcanic islands that were formed in the Zubair archipelago of the southern Red Sea in 2011–2013. Using high-resolution optical satellite images, we find that the new islands grew rapidly during their initial eruptive phases and that coastal erosion significantly modified their shapes within months. Satellite radar data indicate that two north–south-oriented dykes, much longer than the small islands might suggest, fed the eruptions. These events occurred contemporaneously with several local earthquake swarms of the type that typically accompany magma intrusions. Earthquake activity has been affecting the southern Red Sea for decades, suggesting the presence of a magmatically active zone that has previously escaped notice.

Cyphastrea kausti sp. n. (Cnidaria, Anthozoa, Scleractinia), a new species of reef coral from the Red Sea

A new scleractinian coral species, Cyphastrea kausti sp. n., is described from 13 specimens from the Red Sea. It is characterised by the presence of eight primary septa, unlike the other species of the genus, which have six, ten or 12 primary septa. The new species has morphological affinities with Cyphastrea microphthalma, from which it can be distinguished by the lower number of septa (on average eight instead of ten), and smaller calices and corallites. This species was observed in the northern and central Red Sea and appears to be absent from the southern Red Sea.

Magmatism on rift flanks: Insights from ambient noise phase velocity in Afar region

AbstractDuring the breakup of continents in magmatic settings, the extension of the rift valley is commonly assumed to initially occur by border faulting and progressively migrate in space and time toward the spreading axis. Magmatic processes near the rift flanks are commonly ignored. We present phase velocity maps of the crust and uppermost mantle of the conjugate margins of the southern Red Sea (Afar and Yemen) using ambient noise tomography to constrain crustal modification during breakup. Our images show that the low seismic velocities characterize not only the upper crust beneath the axial volcanic systems but also both upper and lower crust beneath the rift flanks where ongoing volcanism and hydrothermal activity occur at the surface. Magmatic modification of the crust beneath rift flanks likely occurs for a protracted period of time during the breakup process and may persist through to early seafloor spreading.

Phytoplankton phenology indices in coral reef ecosystems: Application to ocean-color observations in the Red Sea

Phytoplankton, at the base of the marine food web, represent a fundamental food source in coral reef ecosystems. The timing (phenology) and magnitude of the phytoplankton biomass are major determinants of trophic interactions. The Red Sea is one of the warmest and most saline basins in the world, characterized by an arid tropical climate regulated by the monsoon. These extreme conditions are particularly challenging for marine life. Phytoplankton phenological indices provide objective and quantitative metrics to characterize phytoplankton seasonality. The indices i.e. timings of initiation, peak, termination and duration are estimated here using 15years (1997–2012) of remote sensing ocean-color data from the European Space Agency (ESA) Climate Change Initiative project (OC-CCI) in the entire Red Sea basin. The OC-CCI product, comprising merged and bias-corrected observations from three independent ocean-color sensors (SeaWiFS, MODIS and MERIS), and processed using the POLYMER algorithm (MERIS period), shows a significant increase in chlorophyll data coverage, especially in the southern Red Sea during the months of summer NW monsoon. In open and reef-bound coastal waters, the performance of OC-CCI chlorophyll data is shown to be comparable with the performance of other standard chlorophyll products for the global oceans. These features have permitted us to investigate phytoplankton phenology in the entire Red Sea basin, and during both winter SE monsoon and summer NW monsoon periods. The phenological indices are estimated in the four open water provinces of the basin, and further examined at six coral reef complexes of particular socio-economic importance in the Red Sea, including Siyal Islands, Sharm El Sheikh, Al Wajh bank, Thuwal reefs, Al Lith reefs and Farasan Islands. Most of the open and deeper waters of the basin show an apparent higher chlorophyll concentration and longer duration of phytoplankton growth during the winter period (relative to the summer phytoplankton growth period). In contrast, most of the reef-bound coastal waters display equal or higher peak chlorophyll concentrations and equal or longer duration of phytoplankton growth during the summer period (relative to the winter phytoplankton growth period). The ecological and biological significance of the phytoplankton seasonal characteristics are discussed in context of ecosystem state assessment, and particularly to support further understanding of the structure and functioning of coral reef ecosystems in the Red Sea.

Evidence for and relationship between recent distributed extension and halokinesis in the Farasan Islands, southern Red Sea, Saudi Arabia

This paper presents a structural evolution study of the Farasan Bank using an integration of field work, remote sensing data, and regional Bouguer gravity data interpretation. The architecture of the Farasan Islands is influenced by normal faults parallel to the Red Sea rift axis delineating a series of graben and asymmetric half-graben structures as well as salt domes. Geological data suggest that the negative gravity anomaly over the Farasan Bank reflects thick salt deposits. The gravity data shows a general NW-SE trend with the main negative anomaly coincident with the Farasan Islands. Gravity data together with seismic reflection data suggest that salt diapirs are elongated and parallel to the main rift orientation (NW-SE). This indicates that salt deposition and diapirism was controlled by rift-related basement structures. Forward modeling of gravity data constrained by marine seismic reflection interpretation reveals that the evaporites directly overlie the basement in most places. No pre-evaporite formation was detected. Integration of the modeling with field observations and interpretations suggests that the Farasan Islands are in an area of active extension. Extension and salt diapirism on the flank of the mid-ocean ridge is likely to be synchronous with renewed spreading at 5 Ma.

Seismicity and seismotectonics of the Red Sea Region

The historical seismicity of the Red Sea region between latitudes 13 and 30° N and longitudes 32 and 46° E has been revised. It is found that during the last 1400 years, some 88 historical earthquakes have occurred with magnitudes M ≥ 5.6. Only two M = 7.0 are reported, one in each of the northern and southern Red Sea regions, followed by two and one 6.8 in the northern and southern regions, respectively. During the period 1960–2010, some 1310 instrumental earthquakes have occurred in the region with M ≥ 4.0. The largest (M = 7.1) occurred in the Gulf of Aqaba, followed by a 6.9 in the entrance of the Gulf of Suez, followed by a 6.7 and a 6.4 that occurred in the southern Red Sea region. All others had M ≤ 6.2. More than 90 % of the seismicity has occurred in the form of sequences and swarms and are believed to be volcanic related. Thus, the seismic hazard of the study region remains quite limited. Both northern and southern parts of the Red Sea region are of comparable seismic activities, while that of the central part is of lower activity. The historical and instrumental seismicity data show excellent correlation with the general tectonics of the study region. These also show that earthquake activity has fluctuated with time from one region to the other. In the Red Sea proper, more than 83 % of the seismic moment is associated with the regional faults of the axial trough with noticeable concentration of activity where the NE trending strike-slip faults cross this trough. Published fault plane solutions for the largest instrumental earthquakes of the last few decades show that both normal and strike-slip faults are active in support of a divergent environment between the Arabian and African plates. Shallow seismicity is a characteristic feature of this region. The data indicates that lithospheric deformations beneath the gulfs area are restricted to the upper part of the crust, while beneath the Red Sea south of latitude 27.8°, these appear to concentrate partially within the crust down to 10 km depth and much more within the uppermost mantle, mostly from 20.1 to 40 km depths. Very little earthquakes occur at depths deeper than 60 km. Frequency-magnitude results of both historic and instrumental data gave the expected b value close to 1.0. The calculated recurrence periods for earthquakes with M = 6, 6.5 and 7 are 30 ± 2 years, 150 ± 10 years and 600 ± 20 years, respectively. The data show that the threshold magnitude for the study region is 4.0, and slightly more for the axial trough.

New records of Lobatolampea tetragona (Ctenophora: Lobata: Lobatolampeidae) from the Red Sea

Lobatolampea tetragona Horita, 2000, a member of the monotypic family Lobatolampeidae (Lobata), is reported from the Red Sea based on seven specimens collected during marine biodiversity surveys conducted in the southern and central Red Sea. The ctenophore is characterized by the following characters: paired oral lobes lacking visible auricles and bearing auricular ctenes; subpharyngeal meridional canals bearing aboral blind ends; and c-shaped gonads. Previously, the species was recorded only from Japanese waters. This finding represents the first record of L. tetragona outside of the North Pacific and represents a substantial range expansion for this species.

Platyceps rhodorachis (JAN, 1863) - a study of the racer genus Platyceps BLYTH, 1860 east of the Tigris (Reptilia: Squamata: Colubridae)

Platyceps rhodorachis (Jan, 1863) is a euryoecious polytypic racer distributed from NE Iraq to Central Asia (Kyrgyzstan) and the Himalayas (probably westernmost Nepal). The nominotypical subspecies, occupying most of the species’ range, is polymorphic. The typical (striped) phenotype is absent from certain peripheral areas. Notable geographic variation is observed in the number of ventrals, subcaudals, dorsal scales, or maxillary teeth and in the colour pattern. P. r. ladacensis (Anderson, 1871) is only found from the eastern Hindu Kush into northern Himachal Pradesh (India). Its presence south of the Zanskar Range requires confirmation and the status of the Ladakh Cliff Racer is debatable. The identity and systematic position of racers from the vicinity of Ahvaz (Khuzestan) as well as Arabian and southern Red Sea populations commonly assigned to P. rhodorachis pend further investigation. Platyceps semifasciatus Blyth, 1860 is a senior subjective synonym of P. rhodorachis (nomen protectum, valid type species of Platyceps Blyth). P. ventromaculatus (Gray, 1834) from the Makran coast to low-lying NW India and Nepal, for a long time confused with Jan’s Cliff Racer (P. rhodorachis sensu stricto), is a mostly parapatric species. Two new taxa of the rhodorachis species group from montane NE Baluchistan Province (P. noeli sp. nov.) and the southern Indus Plain (P. sindhensis sp. nov.) are described. Another racer taxon from northern Azad Jammu and Kashmir remains undesignated. Distinctive morphological character states for P. rhodorachis vis-à-vis the southeast Mediterrano-Iranian P. najadum (Eichwald, 1831), P. karelini (Brandt, 1838) from Libya to the Lake Balqash area and inland SW Pakistan (hybridises in places with P. r. rhodorachis), Baluch endemics including P. mintonorum (Mertens, 1969), and Sindian species (sindhensis, ventromaculatus) are elaborated. An identification key embracing the Indian P. bholanathi (Sharma, 1976) and P. gracilis (Günther, 1862) as well as a review of Platyceps Blyth are provided. This genus is currently comprised of twenty-three mainly southern Palaearctic and Afrotropical as well as two Indian species referred to three (florulentus, najadum, rhodorachis-ventromaculatus) evolutionary lineages.

Towards a Chronology of the Eritrean Red Sea Port of Adulis (1st – Early 7th Century AD)

The Eritrean coastal site of Adulis has been known to archaeologists since the second half of the 19th century. At the beginning of the 20th century, the Italian archaeologist Roberto Paribeni conducted extensive excavations in different areas of the site which uncovered the remains of monumental buildings, churches and houses, as well as rich deposits of related material culture. Since then, archaeological investigations have been limited to the activities of Francis Anfray in 1961–62 and to a survey conducted by the University of Southampton in 2003–04. Our team’s first excavations in stratified deposits began in 2011, and soon revealed a complex chronological sequence of great importance for the understanding of the cultural history of the southern Red Sea region and the Horn of Africa. The project’s main efforts were directed towards the identification of the main phases of occupation at Adulis, the establishment of a typological sequence of pottery, and the analysis of architectural change.

The Farasan Islands, Saudi Arabia: towards a chronology of settlement

An archaeological survey of Saudi Arabia's Farasan Islands in May 2010 recorded a broad range of sites that have not previously been documented. The survey concentrated on Greater Farasan and Segid islands, and comprised a rapid recording of sites shown to the authors by representatives of the Saudi Commission for Tourism and Antiquities. The sites were photographed, their positions logged, sketch drawings made of the principal features and surface pottery drawn and photographed. Detailed drawings were made of a stone anchor and a well with possible Ancient South Arabian carved decoration. The sites visited included settlements, wells, cemeteries and a cave. Several sites included the remains of buildings made of massive ashlar blocks, as well as others of rubble‐stone construction. Datable material at the sites points to several periods of occupation, from the early first millennium BC to early modern times. Some locations were characterised by long periods of settlement. Apart from the findings of this survey, most of the sites remain largely uninvestigated, and suggest significant potential for future research into settlement on the archipelago, as well as into past maritime activity and technology in the southern Red Sea region and beyond.

Survey of demersal fishes from southern Saudi Arabia, with five new records for the Red Sea.

During a survey of demersal fishes of the southern Red Sea coast of Saudi Arabia off Jizan, 98 species were collected by trawling. Five of these represent new records for the Red Sea: Saurida longimanus, Dactyloptena gilberti, Jaydia novaeguineae, Pomadasys maculatus and Parapercis maculata. Additionally a specimen of the rare moray Gymnothorax reticularis, previously known from only three specimens, was collected. Records of two species, Parastromateus niger and Pseudorhombus arsius, that formerly were considered questionable, are confirmed by collection of new voucher specimens. Validity of Laeops sinusarabici is confirmed. This study documents parts of the diversity of the demersal fish communities on sandy areas of the southern Red Sea, but also emphasizes that a large proportion of this area has not been explored.

Movement patterns of juvenile whale sharks tagged at an aggregation site in the Red Sea.

Conservation efforts aimed at the whale shark, Rhincodon typus, remain limited by a lack of basic information on most aspects of its ecology, including global population structure, population sizes and movement patterns. Here we report on the movements of 47 Red Sea whale sharks fitted with three types of satellite transmitting tags from 2009–2011. Most of these sharks were tagged at a single aggregation site near Al-Lith, on the central coast of the Saudi Arabian Red Sea. Individuals encountered at this site were all juveniles based on size estimates ranging from 2.5–7 m total length with a sex ratio of approximately 1∶1. All other known aggregation sites for juvenile whale sharks are dominated by males. Results from tagging efforts showed that most individuals remained in the southern Red Sea and that some sharks returned to the same location in subsequent years. Diving data were recorded by 37 tags, revealing frequent deep dives to at least 500 m and as deep as 1360 m. The unique temperature-depth profiles of the Red Sea confirmed that several whale sharks moved out of the Red Sea while tagged. The wide-ranging horizontal movements of these individuals highlight the need for multinational, cooperative efforts to conserve R. typus populations in the Red Sea and Indian Ocean.

Late quaternary glacial/interglacial cyclicity models of the Red Sea

The benthic foraminiferal faunas from samples of two piston cores retrieved along a north–south transect in the Red Sea were studied. The northern core was collected during Meteor cruise M 31/2, while the southern one was collected during the Sonne cruise 121. Benthic foraminiferal faunas from both sites exhibit large variability with respect to density, diversity, species composition and assemblages combined with stable oxygen and carbon isotope records of planktic and benthic foraminifera. One hundered thirty benthic foraminiferal species were identified in the investigated cores. The faunal data set of the northern core was reduced to five assemblages (factors) while the southern one was reduced to four assemblages. All assemblages were ranked according to their ecological significance. Besides, relative abundance of major benthic foraminiferal suborders [Textulariina (agglutinating foraminifera), Miliolina and Rotaliina], in addition to infaunal/epifaunal relative abundance were used as paleoenvironmental proxies allowing the reconstruction of past changes in deep-water salinity, ventilation and organic carbon fluxes at the sea-floor. Four distinct glacial/interglacial cycle during the past 380 Kyr have been recognized in the Red Sea. The identified four cycles reveal deviation in deep-sea ecosystem between the northern and southern Red Sea. In the northern Red Sea salinity fluctuations, productivity and deep-water ventilation and formation had the major impact on benthic foraminiferal pattern corresponding to glacial/interglacial cycles and glacio-eustatic sea level changes coupled with the impact of Mediterranean climate regime. On the otherhand, in the southern Red Sea region the oscillation trend of benthic foraminiferal pattern within the glacials and interglacials stages indicates a high frequency environmental alternation. This alternation is consistent with the extent of NE monsoonal wind that controls the intensity and extension of the productivity, which in turn determine organic matter fluxes and oxygen level at the sea floor.