Environmental Conditions of Two Red Sea Coastal Lagoons in Jeddah. 1. Hydrochemistry

1998 ◽  
Vol 9 (1) ◽  
pp. 31-47 ◽  
Author(s):  
OSMAN EL-RAYIS ◽  
MUSTAFA MOAMMAR
2021 ◽  
Author(s):  
M. Clara Modenesi ◽  
J. Carlos Santamarina

<p>The demand for metals and raw materials continues to increase as onshore deposits become more depleted. Our oceans contain large unexplored areas that may contain new resources in the form of Mn-nodules, Co-rich crusts, and massive sulfides. A complete characterization and assessment of these deposits are fundamental for the evaluation of resource extraction, separation, and disposal processes.</p><p>The Red Sea holds unique examples of sediment accumulations formed under distinctive environmental conditions. The Atlantis II deep is located in the central part of the Red Sea at 2 km depth and on top of the spreading axis. This deep accumulates sediments that result predominantly from the discharge of hydrothermal fluids into hot and stratified brine pools. The changes in environmental conditions and the hydro-chemical conditions in the brine pool control sediment formation. The accumulations are enriched with metals, such as Ag, Au, Cu, Co, and Zn. The sediments in this deep hold a record of the formation history and their brine pools tell a story about on-going processes.</p><p>On-going research at the Energy Geo-Engineering Laboratory EGEL, KAUST includes (1) Geotechnical index properties (liquid limit, grain size distribution, and specific surface) and consolidation tests to infer engineering properties, (2) Sediment classification based on the Revised Soil Classification System, (3) Geochemistry and mineralogy using XRD, ICP-OES and (4) Microstructure and texture with SEM imaging. An advanced sediment characterization of these fine-grained metalliferous deposits gives a comprehensive understanding of the soil behavior.</p>


2019 ◽  
Vol 11 (1) ◽  
pp. 426-439
Author(s):  
Ali S. Basaham ◽  
Ibrahim M. Ghandour ◽  
Rabea Haredy

Abstract Geochemical and mineralogical analyses of bottom sediments collected from Al-Shuaiba (SHL) and Al-Mejarma (MJL) coastal lagoons, Red Sea were carried out. Mineralogically, the sediments consist mainly of carbonate minerals particularly aragonite, high and low Mg-calcite and traces of dolomite admixed with non-carbonate minerals including quartz, k-feldspars, plagioclase and traces of amphiboles, mica and clay minerals. The spatial distribution of major and trace elements at the bottom of the lagoons indicates two groups of elements. The first, less significant, is of terrigenous origin concentrates mainly in the shoreward direction. This group includes the silicates (Al2O3-Fe2O3-SiO2), Feldspars (K2O-Rb-Ba) and heavy minerals (V-Cr-Zr, TiO2-Y-Nb) related elements. The second most dominant group is the carbonate related elements (CaO-Sr) that concentrates in the seaward direction. The two lagoons are not affected by urbanization or anthropogenic impact, and hence the siliciclastic elements are related to the terrigenous influx mainly by aeolian transportation. The carbonate related elements are mainly of biogenic origin related to calcareous skeletal remains. The elemental distribution in the bottom sediments of the MJL is more homogeneous than those in the SHL reflecting the bottom conditions that are mainly controlled by lagoon morphology, hydrodynamic and the water circulation between the lagoon and the sea. Geochemical data show no obvious enrichment of Al-normalized redox-sensitive trace elements V and Cr suggesting that there is no variation in the bottom redox conditions in contrast with other previous studies. The information in this work is an important tool for biogeochemical and biological research projects in the Red Sea coastal lagoons.


1957 ◽  
Vol 8 (2) ◽  
pp. 111 ◽  
Author(s):  
C Crossland

This is an abbreviated form of the original manuscript prepared by the author following 16 years' work at Dongonab Bay in the Red Sea in an attempt to establish a pearl oyster cultivation industry. The environmental conditions at Dongonab, the species of pearl oysters in the Red Sea, and the detailed biology of Pinctada margaritifera (L.), the species used for the experiments, are discussed. Details are given of the methods developed for the collection of spat and the cultivation of the pearl-shell to marketable size. It was unfortunate that the improvements designed in 1921 were not used for commercial production, because the Sudan Government did not continue the scheme.


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