Level of some major constituents of the Egyptian Mediterranean Coastal waters

Level of some major constituents of the Egyptian Mediterranean
Coastal waters
Ramzy B. Nessim, Dalia. M. S. A. Salem, Safaa. A. H. Abdel Ghani
and Amal E. A. Abou-Taleb
National Institute of Oceanography and Fisheries, Kayet Bey, Alexandria, Egypt.
E-mail: [email protected]
Received 9th July 2009, Accepted 14th November 2009
Abstract
Investigation of the chemical composition of the Egyptian Mediterranean coastal water at the end of 20th and
the beginning of the 21st century was carried out. The study of some major constituents is based on a large number
of samples taken through four cruises (August 2000 and March 2001) along 8 sections lie perpendicular to the coast
starting from Sahl El-Tina in the east in Barani to the west. The water column till 200 m depth at (3-4) locations
along each section was subjected to determination of salinity, total dissolved salts, calcium, magnesium, sulphate
and bromide contents. The ionic relationships and salinity levels were discussed. With respect to the total average
concentration of the analyzed samples, the respective studied variables levels were as follows: 38.22‰, 39.55 g/l,
403.4 mg/l, 1585.8 mg/l, 63.6 mg/l and 2.75 g/l for salinity, TSD, Ca2+, Mg2+, Br–
and SO4
2– respectively. Most of
these ions /chlorinity ratios and their averages reflect variety of deviations from the corresponding normal oceanic
levels. Only few data give chlorinity ratios nearly similar to those of ocean. Most of Ca2+, Br–
and SO4
2–/chlorinity
ratios reveal negative declinations below the oceanic ones while Mg2+/Cl–
ratios of most data display positive
declination above normal which indicate a relative excess of Mg2+ ions along the coast. The Mg/Ca ratio average
computed for all samples (3.9) is higher than normal (3.0) and realize this phenomenon. The intrusion of relative
low saline water from Atlantic Ocean, the land based effluents at different hot spots areas, the high rate of
evaporation in addition to many physical, chemical and biological processes affect the salinity and consequently the
major ions levels and their chlorinity ratios either spatially or temporary to a certain extent. Insignificant correlation
coefficients between Ca and other studied variables content were found for winter data. The near shore results of
summer cruises display good correlations between Ca2+ and each of Mg2+ and salinity being, r = 0.415 and 0.768,
p<0.02, respectively. Direct significant correlations were also computed between Mg2+ and each of Br– and salinity in the winter surface samples, being 0.483 & 0.448 respectively (p<0.01). Keywords: Mediterranean Coast, Major constituents, Chlorinity ratio, Total dissolved salts, Egypt .