scholarly journals Diagenetic rejuvenation of raised coral reefs and precision of dating. The contribution of the Red Sea reefs to the question of reliability of the Uranium-series datings of middle to late Pleistocene key reef-terraces of the world

2008 ◽  
Author(s):  
Jean-Claude PLAZIAT ◽  
Jean-Louis REYSS ◽  
Abdelmajid CHOUKRI ◽  
Charlotte CAZALA
Keyword(s):  
Coral Reefs ◽  
Red Sea ◽  
Late Pleistocene ◽  
Uranium Series ◽  
The World

Fossil molluscan fauna reflects zonation of a Late Pleistocene reef of the Red Sea

2021 ◽  
Author(s):  
Anna Haider ◽  
Angelina Ivkić ◽  
Andreas Kroh ◽  
Abbas Mansour ◽  
Martin Zuschin
Keyword(s):  
Coral Reefs ◽  
Red Sea ◽  
Late Pleistocene ◽  
Reef Flat ◽  
Patch Reef ◽  
Alpha Diversity ◽  
Reef Slope ◽  
Soft Bottom ◽  
Last Interglacial ◽  
Gastropod Species

<p>Many studies focus on modern coral reefs and their associated invertebrate fauna, but not much is known about the paleoecology and diversity of molluscs of Late Pleistocene coral reefs, which were formed during the last interglacial MIS5e. This study is investigating the molluscan assemblage of a Late Pleistocene coral reef in southern Egypt, at the locality Sharm El Luli, in the area of Marsa Alam. The locality is characterized by a variety of reef- and reef associated habitats, including a reef flat, reef slope, a patch reef, and soft bottoms of a lagoon and in the backreef area. We quantitatively and qualitatively sampled 10 sites with a total of 79 samples and collected 2126 shells, which belong to 177 taxa, mostly identified to the species level.   Most taxa were found with the qualitative sampling approach. The most abundant bivalves taxon was the epifaunal, encrusting <em>Chama </em>spp., the most abundant gastropod species was the cerithiid <em>Rhinoclavis vertagus</em>. Regarding the life habitats most bivalve species are infaunal filter feeders, while most gastropods are epifaunal carnivores.    Alpha diversity is highest in the coral patch and in the upper reef region, which implies the reef slope, the reef flat as well as the transition between reef slope and the lagoon. Preliminary statistical results suggest a division in coral-patch, lagoon and backreef as well as a cluster of upper-reef habitats. From these two broad environments can be distinguished: hard bottoms associated to reefs and reef-associated soft bottom environments. The former are best characterized by encrusting taxa such as <em>Chama </em>spp. and <em>Spondylus </em>spp., and by <em>Tridacna maxima</em> and <em>Perigylypta </em>spp., which are well-known reef associates. Gastropods in this environment are predatory conids and cypraeids. All of these species live on - or occur cryptically in - structured hard bottoms. Reef associated-soft bottom environments are best characterized by infauna, such as the tellinid <em>Quidinipagus palatam</em> and the lucinids <em>Anodontia kora</em> and <em>Pillucina vietnamica</em>. Furthermore, many soft bottom gastropod species such as the strombid <em>Gibberulus gibberulus albus</em>, the cerithiid <em>Rhinoclavis vertagus</em>, both with an herbivorous diet, and the nassariid <em>Nassarius fenistratus</em>, a scavenger, can be found here.  A comparison with modern datasets from the Red Sea indicates strong similarities in faunal composition and habitat diversity between fossil and recent reefs.  Furthermore, our preliminary results suggest that Late Pleistocene molluscan assemblages can aid in reconstruction of associated fossil reef habitats. </p>

Unexpected abundance: Millepora corals in Late Pleistocene reefs of Egypt

2021 ◽  
Author(s):  
Angelina Ivkić ◽  
Andreas Kroh ◽  
Abbas Mansour ◽  
Martin Zuschin
Keyword(s):  
Coral Reefs ◽  
Red Sea ◽  
Fossil Record ◽  
Habitat Preferences ◽  
Geographic Location ◽  
Scleractinian Corals ◽  
Skeletal Structure ◽  
The World ◽  
Preservation Potential ◽  
Fossil Reef

<p>Coral reefs throughout the world are well known for the dominance of scleractinian corals. However, one group of hydrozoan corals can be very common in modern tropical coral reefs as well: <em>Millepora</em>, the fire coral. The modern Red Sea is particularly well known for its high abundances of <em>Millepora</em>, where the fire coral is dominant on current-exposed reefs. Yet, this hydrozoan has been described as rare in the fossil record throughout the world and the documented abundances in fossil reefs do not match the numbers from modern reefs. The main interpretation to explain this phenomenon so far has been a lower preservation potential of milleporids compared to scleractinians due to differences in skeletal structure.</p><p>During an investigation of six Eemian Egyptian reef sites (29 line intercept transects, typically of 20 m length) we found <em>Millepora</em> in 69% of the fossil reef transects. The abundances were comparable to the adjacent modern reefs (65.13% to 0.26%). Preservation of fossil <em>Millepora</em> was good to excellent and in some cases well-preserved pore characters allowed for identification to species level. Our findings seem to be in stark contrast to results and interpretations of earlier studies, which suggest that <em>Millepora</em> is very rare in the fossil record globally. To understand the reason for this mismatch, we compared the associated scleractinian fauna between fossil reefs with and without <em>Millepora</em> presence. Furthermore, as a differentiation between shallower habitats close to the reef edge and deeper habitats along the reef slope was possible, we were able to investigate habitat preferences. <em>Porites</em> abundances were higher in fossil reefs without <em>Millepora</em>. Based on a comparison with modern communities, this suggests that the exposure to water energy might be a decisive factor for <em>Millepora</em> presence in the fossil reef. Therefore, preservation and consecutive investigation of appropriate fire coral-habitats is a pre-requisite for valid comparisons.</p><p>Another factor for the mismatch between our results and earlier studies might be a difference in diagenetic conditions that allow preservation of hydrozoan skeletons in the fossil record. Preservation of the investigated Egyptian sites is favored by their young geological age and their geographic location in a desert climate, reducing dissolution by aggressive meteoric waters. Furthermore, the extremely high abundance of <em>Millepora</em> in modern Red Sea coral reefs may in part mitigate the lower preservation potential of the hydrozoan skeleton in comparison with that of scleractinian corals.</p>

Stratigraphic and Tectonic Implications of Uranium-Series-Dated Coral Reefs from Uplifted Red Sea Islands

1991 ◽  
Vol 35 (2) ◽  
pp. 264-273 ◽  
Author(s):  
Chi Trach Hoang ◽  
Marco Taviani
Keyword(s):  
Coral Reefs ◽  
Red Sea ◽  
Series Method ◽  
Sea Islands ◽  
Uranium Series ◽  
Tectonic Implications ◽  
Two Systems

AbstractCorals from raised reef terraces on two islands (Zabargad and Northern Brother), considered to have been tectonically uplifted in connection with the Red Sea rifting, were dated with the U-series method. At Zabargad, there are at least three systems of raised coral reefs. The oldest terrace (>290,000–300,000 yr B.P.) is found at +10 to +15 m. A 200,000 yr B.P. high-sea stand is recorded by a terrace relict at +17 m on peridotite bedrock; the youngest system (125,000–138,000 yr B.P.) is very well represented around the island, with terraces at about +6 to +8 m. Corals from Northern Brother yield ages of 132,000–135,000 and 204,000 yr B.P. suggesting the existence of two systems of interglacial raised reefs. Both islands appear to have been tectonically quite stable since at least 125,000 yr B.P.

scholarly journals What Lives in the Ocean? An Introduction to the Biodiversity of the Red Sea

2021 ◽  
Vol 9 ◽  
Author(s):  
Marcelle M. Barreto ◽  
Marcela Herrera ◽  
Manuel Aranda
Keyword(s):  
Coral Reefs ◽  
Red Sea ◽  
Well Being ◽  
Marine Turtles ◽  
The World

Have you ever wondered how many species are out there? Biodiversity refers to all the different plants and animals in the world, and it is incredibly important for our well-being. All organisms have a role in the environment, and healthy ecosystems depend on high biodiversity. For example, tiny plant-like organisms living in the ocean are responsible for most of the oxygen we breathe. Mangroves and coral reefs are homes for many wonderful fish, and they protect our coastlines from storms. The Red Sea is one of the world’s most biodiverse oceans. It is a unique home to many different species that cannot be found anywhere else in the world. Scientists have estimated that there are around 29 species of sharks, 17 of whales and dolphins, 5 of marine turtles, 1,078 of fish, 359 of hard corals, and many more invertebrates. Imagine all the tiny microorganisms that we cannot see!

Palaeolithic Cave Art at Creswell Crags in European Context

2007 ◽  
Keyword(s):  
Late Pleistocene ◽  
Rock Art ◽  
Ice Age ◽  
Upper Palaeolithic ◽  
Southern France ◽  
European Context ◽  
The World ◽  
Cave Art ◽  
Illustrated Book

Cave art is a subject of perennial interest among archaeologists. Until recently it was assumed that it was largely restricted to southern France and northern Iberia, although in recent years new discoveries have demonstrated that it originally had a much wider distribution. The discovery in 2003 of the UK's first examples of cave art, in two caves at Creswell Crags on the Derbyshire/Nottinghamshire border, was the most surprising illustration of this. The discoverers (the editors of the book) brought together in 2004 a number of Palaeolithic archaeologists and rock art specialists from across the world to study the Creswell art and debate its significance, and its similarities and contrasts with contemporary Late Pleistocene ("Ice Age") art on the Continent. This comprehensively illustrated book presents the Creswell art itself, the archaeology of the caves and the region, and the wider context of the Upper Palaeolithic era in Britain, as well as a number of up-to-date studies of Palaeolithic cave art in Spain, Portugal, France, and Italy which serve to contextualize the British examples.

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