Red Sea

The features created by crustal movements may be mountain chains, like the Himalayas, where collision of continents causes extensive compression. Conversely, the depressions of the Red Sea and East African Rift Basin are formed by extensional plate movements. Both type of movements form large scale depressions into which sediments from the surrounding elevated areas ( highs ) are transported. These depressions are termed sedimentary basins (Fig. 2.3). The basin fill can attain a thickness of several kilometres. 

The waters through which ships travel are categorized by their salt content. The following are approximate values seawater, 3.0 to 4.0% salt coastal brackish water, 1.0 to 3.0% river brackish water, 0.5 to 1.8% salty river water, 0.05 to 0.5% river water, <0.05%. Seawater mainly contains NaCl. The salt content is approximately 1.8 times the chloride ion content. The salt content of the world s oceans is almost the same. Different salt contents can occur in more enclosed seas [e.g., the Adriatic (3.9%), Red Sea (4.1%) and the Baltic (1.0%)]. Table 17-1 gives as an example average analyses for seawater and the Rhine River. 

Holy Bible, Exodus, Chap. 15, verses 22-25 "... so Moses brought the sons of Israel from the Red Sea and they went into the desert of Sur. And they marched three days in the wilderness and found no water to drink. And then they arrived at Merra and they could not drink from the waters of Merra because they were bitter.. .. And the people murmured against Moses saying What shall we drink And Moses cried unto the Lord. And the Lord showed him a wood and he put it into the water and the water became sweet . 

Painting of a Phoenician merchant galley, c. 7th century B.C.E., crossing the Red Sea. (Corbis Corporation)... 

Local conditions may modify this profoundly in special areas. In the Arctic and Antarctic, and where there is dilution by large rivers, the salinity may be considerably less, and it may vary greatly according to season. Salinity is well below normal in the Baltic, and may fall nearly to zero at the head of the Gulf of Bothnia. In enclosed seas like the Mediterranean, Black Sea and Red Sea, on the other hand, where there is rapid evaporation, salinity may reach 40 parts per thousand. The total salt content of the inland Dead Sea is 260 g/kg compared to 37 g/kg for the Atlantic Ocean. 

A circumnavigation of the world s oceans between 1978-1980 (18), further indicated that broad expanses of the Atlantic, Pacific, and Indian Oceans away from major tanker lanes and shipping routes contained little or no tar, whereas tar pollution was prevalent in the Mediterranean, Java Sea and Red Sea, and in western European and Northwest African coastal areas. 

Further members of this class of alkaloids are the araguspongines K (10) and L (11), isolated from the marine sponge Xestospongia exigua collected at Bayadha, on the Saudi Arabian Red Sea coast [16]. After evaporation of the EtOH extract, it was partitioned between hexanes and MeCN. The polar fraction was subjected to a series of chromatographic separations by column chromatography on silica gel. The structures of both alkaloids 10 and... 

Oudin, E. and Cocherie, A. (1988) Fish debris record the hydrothermal activity in the Atlantic II Deep sediments (Red Sea). Geochim. Cosmochim. Acta, 52, 177-184. 

N Guaymas Basin 14 Middle Valley 43 Escanaba Trough 32 Atlantic II Red Sea 53... 

Investigations of the natural products chemistry of the Red Sea soft coral Lobophyton depressum (Alcyonacea) led to the isolation of a crystalline prostanoid derivative [70]. On the basis of H NMR data, the planar structure was developed as methyl ll-acetoxy-PGF2tt (56). Stereochemistry at Cl5 was established as S by comparison of the biological and NMR features of the hydrolyzed... 

De Kersabiec et al. [708] have described a Zeeman method for the determination of copper, lead, cadmium, cobalt, nickel, and strontium in brines and in the soil water adjacent to the Red Sea. 

We turn our attention now to the hydrothermal brines of the Red Sea. An oceanic survey in 1963 discovered pools of hot, saline, and metal-rich brines along the axial rift of the Red Sea (Degens and Ross, 1969 Hoffmann, 1991). The dense brines pond in the rift s depressions, or deeps. The Atlantis II deep contains the largest pool, which measures 5 x 14 km and holds about 5 km3 of supersaline brine. The deep holds two layers of brine. The lower brine contains about 25 wt.% dissolved salts and exists at temperatures up to 60 °C. Table 6.8 shows the brine s average composition. A somewhat cooler, less saline water overlies the lower brine, separating it from normal seawater. 

Table 6.8. Chemical composition of the lower brine, Atlantis II deep, Red Sea...

Table 6.9. Calculated molalities (m), activity coefficients (y), and log activities (a) of the most abundant species in the Red Sea brine...

Starting with a dilute solution, for each doubling of the activities of the free ions on the left of these reactions, the activities of the ion pairs on the right sides must quadruple. As concentration increases, the ion pairs become progressively more important and eventually can come to overwhelm the free ions in solution. The higher temperature of the Red Sea brine also favors complexing because ion pairs gain stability relative to free ions as temperature increases. 

We can check our results for the Red Sea brine against two independent pieces of information. In our results, sulfate species such as NaSO dominate reduced sulfur species such as H2S(aq) and HS-, in seeming accord with the failure of analysis to detect reduced sulfur in the brine. The predominance of sulfate over sulfide species in our calculation reflects the oxidation state resulting from our assumption of equilibrium with sphalerite. 

Degens, E.T. and D. A. Ross (eds.), 1969, Hot Brines and Recent Heavy Metal Deposits in the Red Sea. Springer-Verlag, New York. 

Messiha, N.N. and N.E. Ikladious. 1986. Antifouling performance of some new organotin polymers in the Mediterranean and Red Sea. Jour. Controlled Release 3 235-242. 

Yamada, H., M. Tateishi, and K. Takayanagi. 1994. Bioaccumulation of organotin compounds in the red sea bream (Pagrus major) by two uptake pathways dietary uptake and direct uptake from water. Environ. Toxicol. Chem. 13 1415-1422. 

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