The last of these

factors is now of minor importance, and hence any distribution of salinity is controlled by the other factors. Figure 5 illustrates the long-term variation of surface salinity in the coastal water of the study area during 1964–2008. As mentioned earlier, in 1964, the river discharge was the greatest since 1956, and the surface salinity was very low (26.675 PSU). From 1966 onwards, a considerable decrease in freshwater discharge was recorded and a remarkable increase in salinity Target Selective Inhibitor Library screening was observed. The salinity increased from 28.309 PSU in 1966 to around 38 PSU in the 1970s and reached more than 39 PSU in 2008. The following are the main characteristics of Atlantic Water, observed along the Egyptian Mediterranean coast, deduced from an analysis of the horizontal and vertical distributions of these characteristics in winter and summer. In winter, the surface water temperature varied between 16.6 and 18.5°C, with slightly colder or warmer spots (Figure 6a). There is a general tendency for temperature to increase eastwards, with the lowest values (16.6–16.8°C) observed at longitudes between 26° and 30°E and latitudes 32–33°N, while the highest values are confined

to the eastern part of the study area. A region of water temperature > 18.0°C AZD4547 clinical trial is observed at the offshore stations between longitudes 31°30′ and 32°30′E and latitudes 32–33°N (Figure 6a). The surface salinity changes between 38.60 and 39.30 PSU, with a generally increasing eastward trend (Figure 6b). The most prominent feature of the salinity distribution at the surface is the presence of a nucleus of salinity > 39.00 PSU that lies between longitudes 27 and 29°E. This nucleus is characterized by low temperature (16.6°C) and high density 28.7 σt ( Figure 6c). The above feature coincides with the location of the well-recognized gyre known

as the Mersa Matruh gyre. This gyre is one of several find more such sub-basin scale gyres interconnected by intense jets and meandering currents that were established long ago in the south-eastern Levantine basin by the POEM Group (1992). The Mersa Matruh gyre has been given different names such as the ‘Egyptian anticyclonic gyre’ by Said, 1984 and Said, 1990, ‘The Egypt high’ by Brenner (1989) and the ‘Mersa Matruh gyre’ by Özsoy et al. (1989). The Mersa Matruh gyre is characterized by an anticyclonic circulation from the surface to 500 m depth during the winter and summer seasons (Said & Eid 1994b). The gyre splits into two centres at 50 and 100 m. Below these levels, the gyre intensifies and splits into multiple centres. The eddy centres are shifted horizontally with depth. At 500 m depth, the gyre could be observed during both seasons. These features were also observed by Eid & Said (1995) in their work on the circulation off the Egyptian coast as deduced from steric height distributions.