Environmentally controlled succession in a late Pleistocene coral reef (Sinai, Egypt)

The concept of ecological succession has been frequently applied in the study of ancient reefs. Whereas Paleozoic and Mesozoic reefs are commonly thought to reveal an autogenic primary—climax zonation, patterns in Neogene and Quaternary reefs are much more diverse. Here, we describe a well-preserved late Pleistocene coral reef from Dahab on Sinai Peninsula (Egypt), which shows a distinct zonation that resembles an ecological succession. In contrast to classical examples of ecological successions, species composition, paleoenvironmental conditions, and coral biodiversity of the Dahab reef indicate an allogenic, sea-level controlled community change, from marginal marine to reef slope and back reef. A review of the literature confirms that autogenic, short-term successions are virtually absent in Quaternary reefs. We predict that long generation times of corals make it unlikely that classical autogenic successions develop in reefs at all, unless environmental conditions are unusually stable.     

Bryozoa from northern Red Sea,Egypt: 1 Crisia (Cyclostomata)

Seventy-five bryozoan species were picked from shallow bottom sediments (0–33 m depths) at five sites in the northern Red Sea: El Fanader, Hurghada Harbour, Makkadi Bay, Al Qweh Lagoon and El-Humrawen. Crisia specimens (Cyclostomata) are common and exhibit different variations. Six species were recognised among the specimens collected: Crisia eburnea (Linnaeus), Crisia elongata (Milne-Edwards), Crisia hornesi Reuss, Crisia sertularoides (Audouin), Crisia tenuis MacGillivray and Crisia hurghadaensis n. sp. The present paper deals with these Crisia species; other bryozoan taxa recovered will be published later. Biogeographic study reveals that three of these species are cosmopolitan, and represented by common to abundant occurrences (C. elongata, C. eburnea and C. hornesi). Two species are local endemics, and represented by only rare occurrences (C. sertularoides and C. hurghadaensis n. sp.). One species (C. tenuis) is Indo-Pacific, and is recorded here for the first time in equatorial waters.     

Fluctuations of sea level during the past 400 000 years: the record of Sinai,Egypt (northern Red Sea)

Morphological features such as emerged and submerged terraces and wave-cut notches, as well as modern and dated fossil coral reefs along the coasts of the Red Sea in southern Sinai, provide a record of ten high-and low-stand sea-level events. These events are correlated with peaks in the Milankovitch orbital cycles and with the ¹⁸O curve. The ten Sinai sea-level events correspond to the ¹⁸O substages 1.1, 2.2, 4.2, 5.1, 5.2, 5.3, 5.4, 5.5, 7.1, and 9.3, respectively. The coral reef belt is developed on the margin of a lateral moving lithosphere, which is part of the Dead Sea transform system. based on the regional teetonics of southern Sinai, and assuming a sea-level of 6.5 m above the present sea-level during the last interglacial high stand (substage 5.5), an average uplift rate of 0.085 mm/year is estimated. By removing the tectonic uplift effect, a sea-level curve for the past 400000 years is obtained. On this curve, the calculated elevations (m, in relation to the present sea-level), the isotopic substages and the ages (in ka=thousands of years) of the events 1 through 10, detected in Sinai, are: (1) substage: 1.1, age: 6 ka, elevation: +0.5(±0.2); (2) 2.2, 18 ka,-122(±10);(3) 4.2, 64 ka,-65 (±3); (4) 5.1, 79 ka, +0.3(±1); (5) 5.2, 91 ka,-28(±5); (6) 5.3, 99 ka,-1.5(±1); (7) 5.4, 111 ka,-29(±5); (8) 5.5, 124 ka,+6.5(±2); (9) 7.1, 193 ka,-1.4(±2); and event (10) substage: 9.3, age: 331 ka, elevation: +2.9(±2). Ages of events (1), (8), (9) and (10) are based on U-Th dating; others are deduced from correlations and conceptual models. Elevations are based on field data from onshore and offshore the Sinai.     

Marine reserves along the Sinai Peninsula (northern Red Sea)

The coral world of the northern Red Sea, situated along the shallow waters of the Sinai Peninsula, has been intensively investigated by Israeli scientists during the last decade. Many aspects of these investigations revealed the presence of unique ecosystems which developed mainly after the last postglacial period less than 10,000 years ago! At this time the cooling of the ambient waters swept out most of the neopleistocenic coral formations, and all the richness and diversity of species observed today evolved after those profound events. At present, typical ecoformations, in which the corals comprise the main part, are found in the northern part of the Gulf of Aqaba, around the southern tip (Tiran Straits) of the Sinai Peninsula, and in the shallow parts of the Gulf of Suez. In 1967 teams of our scientists investigated the marine habitats, and a number of marine parks and sanctuaries, protected by law, have been established. Thus destruction of unique faunal elements is being prevented. Today, with the withdrawal of Israel and the return of Egypt to its territories, such parks should receive much attention and remain protected habitats for the benefit of nature and mankind.     

Initial phases in reef development,studied at artificial reef types off Eilat, (Red Sea)

The initial steps in the formation of a coral reef (as distincr from the enlarging of an already existing reef) have been observed at block moles off Eilat (Red Sea). Within a period of 11 years, thus far four phases can be distinguished: (1) start-phase: rapid and homogeneous colonization by fouling organisms, still indeterminant for the final reef development; (2) preparation-phase: settling of shells, calcareous red algae and foraminiferans not affected by grazing animals which largely consume the initial settlers and subsequently attaching larvae; (3) phase of pioneer frame-building: growth of scleractinians and hydrocorals, settled on the remains of rock-attached shells or on other places inaccessible to grazers; secondary frame-builders (e.g.Tridacna) grow in their shelter; (4) phase of frame-binding: dead coral colonies are overgrown by calcareous foraminiferans, algae and bryozoans consolidating the coralline structures by their deposits. Living corals are successively colonized by a specific community (mainly decapods and molluscs); among these, borers are the earliest settlers. Upon death of the coral, there is a complete change in associated organisms forming a less specific but more diverse community.Supported by the Deutsche Forschungsgemeinschaft.     

Benthic foraminifera and trace metal distribution: a case study from the Burullus Lagoon,Egypt

Benthic foraminifera are widely used to detect the health of their habitat, where they are very sensitive to even slight variations in the ecosystem. Therefore, the main objectives of this study are to examine the benthic foraminiferal assemblages in the sediments of Burullus Lagoon, evaluate the pollution levels and deduce the impact of trace metals on foraminifera. The continuous discharge of trace metals from agricultural, industrial and domestic sources into the lagoon may lead to a severe environmental problem. The concentrations of Mn, Cu, Cd, Zn and Pb within the sediments were measured. Recently, the assessment of contamination is principally based on the contamination indices which provide fast and simple quantitative values on the degree of pollution in a given aquatic environment. Thus, some indices, including the contamination factor, the degree of contamination, pollution load index, geoaccumulation index, ecological risk factor and potential ecological risk index are applied in this investigation. Based on the contamination factors, the sediments are very highly contaminated with Cd, considerably to very highly contaminated with Cu and Zn, moderately contaminated with Mn, low to moderately contaminated with Pb. All sites display very high values for the degree of contamination. Moreover, the values of the pollution load index are higher than 1, indicating that the lagoon is polluted. Depending on the geoaccumulation index, the contaminants are arranged as follows Cd > Zn > Cu > Mn > Pb. It is clear that Cd is the main contributor to the ecological risk factor in Burullus Lagoon. Concerning the richness of the foraminiferal assemblages, it fluctuates between 1–5 species per sample. Because of its higher tolerance to extreme conditions (changes in salinity and pollution), Ammonia tepida is the most abundant species. The occurrence of rare living individuals (25) is restricted only to sites close to El-Boughaz Inlet where higher salinity and lower levels of pollution are recorded. The same trend of distribution is shown by Cribroelphidium excavatum and miliolids, where they occur at sites with higher salinities. The occurrence of test deformities in all the studied sites may be related to the response of benthic foraminifera to trace metal. The forms of deformation include spiroconvex, reduced chambers, twisted tests, twinning, additional chamber and complex forms. The deformation depends on the nature of pollutants. Twinning and reduced chambers are the most dominant forms in areas close to the agricultural drainage (southern drains), while complex forms are abundant in areas close to industrial drainage (El-Gharbia drain). Thus, salinity and pollution may be the most regulatory factors controlling the distribution of foraminifera. This investigation confirmed the role of benthic foraminifera as a good ecological indicator in Burullus Lagoon.     

Ascidian recruitment patterns on an artificial reef in Eilat (Red Sea)

Although ascidians are conspicuous members of the fouling community not much is known regarding their recruitment patterns in coral reefs. A 1-year study was carried out along the Red Sea coast of Israel to examine the effects of season and spatial distribution on ascidian recruitment to artificial marine structures. In general, autumn and spring were characterized by higher coverage with a significantly higher percentage of cover of Didemnum granulatum in autumn and higher numbers of Herdmania momus in spring. These species contributed the most to similarity between treatments consequently setting the pattern for each group (colonial and solitary). Halocynthia spinosa had significantly higher numbers during winter and Phallusia nigra was absent in spring and winter. H. momus showed a preference for horizontal surfaces. P. nigra and Ascidia cannelata showed a preference for floating units. It is concluded that the ascidian recruitment patterns are species-specific and vary between seasons, orientation and position on the substrata and in the water column.     

Effect of habitat characteristics on the distribution and abundance of damselfish within a Red Sea reef

For coral reef fish with an obligate relationship to their habitat, like Pomacentrid damselfish, choosing a suitable home amongst the reef structure is key to survival. A surprisingly small number of studies have examined patterns in adult damselfish distributions compared to other ontogenetic phases. The aim of this study was to determine which reef and coral colony characteristics explained adult damselfish distribution patterns in a Red Sea reef. The characteristics investigated were reef type (continuous or patchy), coral species (seven species of Acropora), and coral morphology (coral size and branching density). The focal damselfish species were Dascyllus aruanus, D. marginatus, Chromis viridis, and C. flavaxilla. Occupancy (presence or absence of resident damselfish), group size and fish species richness were not significantly different between the seven Acropora species. However, within each coral species, damselfish were more likely to occupy larger coral colonies than smaller coral colonies. Occupancy rates were also higher in patchy reef habitats than in continuous sections of the reef, probably because average coral colony size was greater in patchy reef type. Fish group size increased significantly with coral colony volume and with larger branch spacing. Multi-species groups of fish commonly occurred and were increasingly likely with reduced branching density and increased coral size.     

Cenomanian-Turonian rudists from Western Sinai, Egypt: Systematic paleontology and paleoecology

The Cenomanian-Turonian sequence is well exposed in western central Sinai and contains a considerable number of rudist species. The identified rudists belong to Radiolitidae, Hippuritidae and Requieniidae. Fifteen species are described, belonging to ten genera: Requienia, Toucasia, Apricardia, Radiolites, Eoradiolites, Praeradiolites, Sphaerulites, Sauvagesia, Hippurites, and Vaccinites. Eleven species are reported in the Cenomanian and four species in the Turonian. Within the Cenomanian, two new species are described: Requienia tortuosi and Eoradiolites lenisexternus. The genus Requienia and the species Apricardia carentonenis d’Orbigny, Eoradiolites syriacus (Conrad), Sphaerulites agariciformis Delamétherie, Sphaerulites depressus Blanckenhorn and Vaccinites cf. grossouvrei (Douvillé) are reported for the first time from Egypt. The Cenomanian and Turonian rudists in the western Sinai show either elevator or clinger morphotypes, with the predominance of the former type; recumbent mode of life is rarely represented by some Requieniidae. The elevators are of isolated and clustered occurrences and more represented in the Cenomanian sequence. Rudists of the study area are mainly of parautochthonous fabrics with low to dense packing. Autochthonous fabrics are also achieved by some species, mainly in the Turonian. The disappearance of rudists from the middle part of the sequence and above the Cenomanian/Turonian boundary is due to a deeper setting that resulted from sea-level rise or seafloor subsidence (shelf drowning). The occurrence of rudists with oysters and other benthic fossils in the siliciclastic and carbonate sediments of the Cenomanian and Turonian sedimentary rocks in the Sinai indicate that the sequence was deposited on a broad, shallow shelf. Although the first marine transgression invaded the central Sinai in the late Cenomanian, transgressive deepening conditions continued until the Turonian. The rudists of central Sinai are of Tethyan affinity with significant relation with North Africa, the Middle East, and Southern Europe.     

Bivalve distribution on coral carpets in the Northern Bay of Safaga (Red Sea, Egypt) and its relation to environmental parameters

Summary Bivalve assemblages on coral carpets in the Northern Bay of Safaga do not form distinct associations, but gradually shift in faunal composition. The taxonomic shift is accompanied by continuous variations in bivalve density and percentage of living individuals as well as by a change of coral associations and potential bivalve habitats. The gradual lateral change of associations is best documented byTridacna maxima and jewel box clams (Chamoidea) and is probably due to variations of the suspension load in the water column. High suspension loads in the water column are additionally indicated by ‘giant oysters’ (extremely large individuals ofHyotissa hyotis) and striking agglomerates ofLopha cristagalli. The vertical differentiation is best documented by the decrease of the zooxanthellateTridacna maxima and is probably due to the depth-dependent light penetration in the water column, which is attenuated in areas of high suspension load.     

Pachyseris inattesa sp. n. (Cnidaria,Anthozoa, Scleractinia): a new reef coral species from the Red Sea and its phylogenetic relationships

A new scleractinian coral species, Pachyseris inattesa sp. n., is described from the Red Sea. Despite a superficial resemblance with some species in the agariciid genus Leptoseris with which it has been previously confused, P. inattesa sp. n. has micro-morphological characters typical of the genus Pachyseris. This genus, once part of the Agariciidae, is comprised of five extant species and is widely distributed throughout the tropical Indo-Pacific. It is currently incertae sedis as a result of recent molecular analysis and appears to be closely related to the Euphylliidae. A molecular phylogenetic reconstruction including P. inattesa sp. n., the genus type species P. rugosa, and P. speciosa, all present in the Red Sea, was performed using the mitochondrial intergenic spacer between COI and 16S-rRNA. The results confirm that P. inattesa sp. n. is a monophyletic lineage closely related to the other Pachyseris species examined.     

Evoxymetopon moricheni,a new cutlassfish from the northern Red Sea (Teleostei: Trichiuridae)

Evoxymetopon moricheni n. sp. is described from the northern Gulf of Aqaba, Red Sea, on the basis of a single specimen. It is characterised within the genus by a convex upper head profile; the posterior confluence of the frontal ridges slightly elevated at the nape, resulting in the presence of a slight sagittal crest; eye 5.2 times in head length; the lower hind margin of opercle slightly pointed in its lower half; the pelvic fins reduced to a scale-like structure with two soft rays on the posterior process of the basipterygium, its origin below the eighth dorsal-fin element; the first anal spine single, oval, scale like, and originating a short distance behind the vent (opposite the 34th dorsal-fin soft ray), anterior anal-fin soft rays minute and embedded, barely penetrating the skin and not visible externally, while the posterior fin supporting the rays enlarged and visible externally; approximately 17 anal-fin rays externally visible; approximately 83 dorsal-fin elements, with first spine not elongate, shorter than second; 12 pectoral-fin rays (ii + 6 + iv), with shorter anterior (fourth ray shortest) and longer posterior rays extending above the lateral line; 10 upper and 13 lower gill rakers of the first gill arch; head and body silver white, with a blackish margin anteriorly on snout and head, continuing along the anterior half of the dorsal-fin base. The new finding represents a new record of the genus from the Red Sea.     

Descriptions of two new species of butterflies (Lepidoptera,Lycaenidae) from the South Sinai

Two new species of lycaenid butterflies, Strymonidia jebelia and Pseudophilotes sinaicus, are described from the high mountains of South Sinai. The foodplants and the eggs of both species are also described with notes on the habitats and adult behaviour. Their relationships with closely allied species and the possible evolutionary histories are discussed.     

Comparison of coral diversity between big and small atolls: a case study of Yongle atoll and Lingyang reef,Xisha Islands,central of South China Sea

The South China Sea (SCS) includes large areas of extensive coral reef development but its reefs are still poorly known. Yongle atoll is the biggest typical atoll in the Xisha Islands, central of SCS. Lingyang Reef is an isolated small atoll within the whole big Yongle atoll. A total of 144 and 119 coral species were recorded at big Yongle atoll and small Lingyang Reef, respectively. The real coral richness might be higher because species accumulation curve did not saturate. The coral diversity pattern was similar between big Yongle atoll and small Lingyang Reef. Coral communities fell into three clusters, consistent with their habitats on reef slope, reef flat and lagoon slope. The highest coral diversity was observed on reef slopes and the lowest coral diversity was found on lagoon slope. Genera richness was a better proxy for representing coral species diversity on both the big and small atoll but percent live coral cover was not a robust proxy on the small atoll, which only explained 24% of species diversity. This study demonstrated high coral diversity with consistent pattern along habitat types, as has been shown from many other reefs. While far from exhaustive, the study allows first glimpses on how much biodiversity is contained on SCS coral reefs, and hopes to give an impetus to their conservation. The study also suggests that simplified surveys at a small scale and the use of genera richness as an effective proxy for overall diversity can indeed provide important information to rapidly monitor and evaluate the coral diversity in remote locations.     

Colonization and bionomics of the sandfly Phlebotomus kazeruni from Sinai, Egypt

Phlebotomuius kazeruni (Diptera: Psychodidae) females were collected by light-trap in southern Sinai, Egypt, and this sandfly species was colonized for the first time as a laboratory strain, maintained by the procedures of Modi & Tesh (1983). Laboratory-reared females did not lay eggs autogenously; they blood-fed more readily (P=0.02) on a hamster (37%) than a human (22%) during 1 h exposure. Fecundity of hamster-fed females was significantly greater than for those fed on human blood: 69.4 +/- 5.8 vs. 45.2 +/- 8.1 eggs/female from the first gonotrophic cycle. Pre-oviposition and egg incubation periods were significantly less for females fed on hamster compared with human blood, but the larval development and pupation periods were not affected by this difference in bloodmeal source. Egg to adult survival was equivalent (38%) for progeny of females blood-fed on hamster or human. The mean generation time of progeny from females fed on hamster (51.9 +/- 1.0 days) or human (53.3 +/- 1.7 days) was not significantly different. The sex ratio of adult male:female progeny was similar (P=0.2) for both hosts: 42:58% from hamster, 46:54% from human blood-fed female parents. Evidently P. kazeruni from Sinai is sufficiently anthropophagic to be a potential vector of Leishmania from rodents to humans.     

Large gryphaeid oysters as habitats for numerous sclerobionts: a case study from the northern Red Sea

The shell of a living specimen of the Indo-Pacific gryphaeid giant oyster Hyotissa hyotis was colonized by numerous encrusting, boring, nestling and baffling taxa which show characteristic distribution patterns. On the upper valve, sponge-induced bioerosion predominates. On the lower valve intergrowth of chamid bivalves and thick encrusting associations—consisting mostly of squamariacean and corallinacean red algae, acervulinid foraminifera, and scleractinian corals—provides numerous microhabitats for nestling arcid and mytilid bivalves as well as for encrusting bryozoans and serpulids. Such differences between exposed and cryptic surfaces are typical for many marine hard substrata and result from the long-term stable position of the oyster on the seafloor. The cryptic habitats support a species assemblage of crustose algae and foraminifera that, on exposed surfaces, would occur in much deeper water.     

Intestinal helminths of spiny mice (Acomys cahirinus dimidiatus) from St Katherine's Protectorate in the Sinai, Egypt

Spiny mice, Acomys cahirinus dimidiatus, inhabiting the wadis close to St Katherine in the mountains of the Sinai peninsula, were trapped and their helminth parasites were studied. Sixty one mice provided faeces for analysis and 27 were killed and autopsied. Six species of helminths were recorded (the spirurid nematodes, Protospirura muricola (74.1%) and Mastophorus muris (11.1%), the oxyuroid nematodes, Dentostomella kuntzi (59.3%), Aspiculuris africana (3.7%), and Syphacia minuta (3.7%) and the hymenolepidid cestode Rodentolepis negevi (18.5%)). The spirurids were the dominant species present, accounting for up to 0.87% of total host body weight. Analysis of worm weights and lengths suggested that transmission had been taking place in the months preceding our study. No sex difference in the prevalence or abundance of spirurids was detected. Significant differences were identified in the abundance of total nematode burdens and the mean helminth species richness between the three wadis which provided multiple captures of mice. There was also a marked effect of host age on both parameters. A highly significant positive correlation between spirurid egg counts and total worm biomass indicated that non-invasive techniques based on egg counts could be used to quantify worm burdens and when this technique was applied to a larger sample size (n = 61), a significant difference between sites but no host sex or age effects were detected for spirurid faecal egg counts. The data suggest that there are differences between helminth component communities infecting spiny mice in different neighbouring wadis, a hypothesis which will be explored further through our continuing studies in the Sinai.     

Sulfate-Reducing Bacteria and Their Activities in Cyanobacterial Mats of Solar Lake (Sinai, Egypt)

The sulfate-reducing bacteria within the surface layer of the hypersaline cyanobacterial mat of Solar Lake (Sinai, Egypt) were investigated with combined microbiological, molecular, and biogeochemical approaches. The diurnally oxic surface layer contained between 10⁶ and 10⁷ cultivable sulfate-reducing bacteria ml⁻¹ and showed sulfate reduction rates between 1,000 and 2,200 nmol ml⁻¹ day⁻¹, both in the same range as and sometimes higher than those in anaerobic deeper mat layers. In the oxic surface layer and in the mat layers below, filamentous sulfate-reducing Desulfonema bacteria were found in variable densities of 10⁴ to 10⁶ cells ml⁻¹. A Desulfonema-related, diurnally migrating bacterium was detected with PCR and denaturing gradient gel electrophoresis within and below the oxic surface layer. Facultative aerobic respiration, filamentous morphology, motility, diurnal migration, and aggregate formation were the most conspicuous adaptations of Solar Lake sulfate-reducing bacteria to the mat matrix and to diurnal oxygen stress. A comparison of sulfate reduction rates within the mat and previously published photosynthesis rates showed that CO₂ from sulfate reduction in the upper 5 mm accounted for 7 to 8% of the total photosynthetic CO₂ demand of the mat.