scholarly journals Space partitioning by stony corals soft corals and benthic algae on the coral reefs of the northern Gulf of Eilat (Red Sea)

1977 ◽  
Vol 30 (1-4) ◽  
pp. 362-382 ◽  
Author(s):  
Y. Benayahu ◽  
Y. Loya
2011 ◽  
Vol 80 (4) ◽  
pp. 251-268 ◽  
Author(s):  
Bert W. Hoeksema ◽  
Andrea L. Crowther

Phyllodiscus semoni is a morphologically variable sea anemone species from the Indo-Pacific with morphotypes ranging from upright and branched to low-lying and rounded. The apparent camouflage strategies of this sea anemone allow it to resemble other species or objects in its environment, such as stony corals, soft corals, seaweeds, or rocky boulders covered by algae, which may help it to avoid recognition by potential predators. Occasionally, it occurs in aggregations that may result from asexual reproduction. A high level of intraspecific morphological variation, including co-occurring aggregations of three different morphotypes, was observed in the Spermonde Archipelago off Makassar, South Sulawesi, Indonesia. The co-occurrence of aggregations with different morphotypes suggests that Phyllodiscus is a highly polymorphic monospecific genus. Sea anemones of this genus are not frequently encountered at other localities and the number of morphotypes seems large. Therefore, it is unlikely that we are dealing with more than one species that are all concentrated in a single area. Phyllodiscus sea anemones are considered dangerous to humans because their nematocysts contain highly toxic venoms that may inflict harmful stings. Therefore they are the subject of recent toxicological studies. The present paper aims to assist in the recognition of these highly variable hazardous animals and to discuss the appearance of their aggregations.


1978 ◽  
Vol 13 (2) ◽  
pp. 180-193
Author(s):  
Ruth Lapidoth

The strait of Bab al-Mandeb, “the gate of tears” or “the gate of the wailing yard”, joins the high seas of the Gulf of Aden and the Indian Ocean to those of the Red Sea. The name is primarily used by geographers to designate the narrowest part of the passage, between Ras Bab al-Mandeb on the Asian shore and Ras Siyan in Africa. At this point it is bordered on the east by the Yemen Arab Republic (Northern Yemen) and the People's Democratic Republic of Yemen (Southern Yemen), and in the west by the Republic of Djibouti (formerly the French Territory of the Afars and Issas). About 14 miles farther north, where the Red Sea (or, for that matter, the strait) is nearly 20 miles wide, lies the coast of Ethiopia (the province of Eritrea). All the riparians claim a territorial sea of 12 miles, and the Yemen Arab Republic, as well as the People's Democratic Republic of Yemen, also claim jurisdiction for certain purposes in an additional zone of 6 miles.On the eastern shore of the strait of Bab al-Mandeb lies the peninsula of Ras Bab al-Mandeb, which is about 6–10 km. wide. It consists of rocky, volcanic plains with several hills of 200–300 m. The coast of Ras Bab al-Mandeb is surrounded by coral reefs of a width of up to 1500 m. The border between North Yemen and South Yemen passes down the middle of Ras Bab al-Mandeb.


2016 ◽  
Vol 10 (6) ◽  
pp. 887-895 ◽  
Author(s):  
Rafat Afifi ◽  
Ismail M. Abdel-Nabi ◽  
Kamal El-Shaikh

2004 ◽  
Vol 48 (3-4) ◽  
pp. 248-253 ◽  
Author(s):  
Jeffrey Wielgus ◽  
Nanette E. Chadwick-Furman ◽  
Zvy Dubinsky

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Leor Korzen ◽  
Alvaro Israel ◽  
Avigdor Abelson

Herbivory is an important structuring factor in coral reefs, influencing seaweed abundance, competitive interactions between seaweeds and corals, and coral reef resilience. Despite reports of a drastic increase in the cover of benthic algae and turf dominancy in the coral reefs of Eilat, Red Sea, very little is known about the factors responsible for this phenomenon or the possible effects of herbivory on turf algae and coral recruits. Here, we examine the effects of herbivory by experimentally exposing turf algae and coral recruits to grazing activities of herbivorous fish and sea urchins. Using remote video cameras to document removal of algae and coral spats, we show that the main grazing impact is due to daily grazing by fishes, whereas the significant impact of sea urchins is mainly expressed in their adverse effect on the survival of coral recruits, with a relatively low effect on algal biomass. These findings contribute to our understanding of the factors influencing turf algae establishment and proliferation, and the survival of coral recruits on the coral reefs of Eilat. The clear differences between the impact of herbivorous fish and that of sea urchins, on the Eilat reefs, have critical implications for reef resilience and restoration measures.


2016 ◽  
Author(s):  
Bemert
Keyword(s):  

2012 ◽  
Vol 446-449 ◽  
pp. 1426-1431
Author(s):  
Zhi Guang Qin ◽  
Yan Luo ◽  
Ying Xi He

Red Sea coral reefs in Saudi Arabia were dredged and reclaimed firstly, and then were treated by dynamic compaction as non-cohesive soil ground. Consolidated condition of improved ground within different depth is in different. Calculating settlements for different state ground should consider actual condition. Several semi-theoretical and semi-empirical settlement calculation methods mainly including Terzaghi’s method(1996), Teng’s method(1969), Meyerhof’s method(1956)are applied and analyzed to investigate the actual condition of improved ground according to the RSGT project test results, and the differences are proposed among these three methods.


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