NATURE AND GEOCHEMISTRY OF SURFACE SEDIMENTS
OF THE MANGROVE ENVIRONMENT ALONG THE
EGYPTIAN RED SEA COAST.
HASHEM. A. MADKOUR AND AHMED W. MOHAMMED
National Institute Oceanography and Fisheries, Red Sea branch Hurghada, Egypt |
Two of the four Red Sea mangrove species were found in the Egyptian Red Sea coast; viz., Avicennia marina and Rhizophora mucronata. Avicennia is widespread through the Egyptian Red Sea coast while Rhizophora mucronata has been located at some sites in the south. In terms of biornass and species diversity, molluscs, warm burrows, snail trails and crabs represent the dominant faunal groups associated with mangroves.
The texture characteristics of mangrove sediments show that the mean size decreases in sediments of coastal areas while increase in island sediments and the sediment type generally charges from sand to slightly gravelly muddy sand. The sediments are composed mainly of poorly-sorted, negatively near symmetrical and leptokurtic fine sands.
Geochemically the factor controlling the carbonate content of studied sediments includes material supply of biogenic and terrigenous components. Therefore, sediments of Hamata area, km 17 south Safaga, Wadi El-Gemal Island and Ahu-Minqar Island are terrigenous sediments, while sediments of km 37 north Quseir are highly carbonates. In general organic matter is higher in the mangrove sediments relative to adjacent areas. Spatial variations in the phosphorus content in the different studied localities are related to the sources of phosphorus to the area.
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