Water Quality Observations in the Dekhaila Harbour, Alexandria, Egypt PDF

Keywords

Eutrophication, nutrients, water quality, plankton biomass, Hydrography, Egypt, Dekhaila Harbour

Abstract

The Dekhaila Harbour, which was recently constructed in Alexandria, has become a highly atrophied area due to intensive maritime activities, and the effect of a mixture of nutrients and different pollutants reaching the harbour through land-based effluent. Environmental observations which were carried out monthly from April 1998 to March 1999 demonstrated extremely high nutrient level and productive phytoplankton, showing wide temporal and spatial variations. The variability of surface salinity was one of the characteristic features of the harbour, falling within the range of 17.3 - 39.2 ppt. Nutrients sustained pronouncedly high values, with annual average of 19.22 nano M for nitrate, 4.16 nano M for nitrite, 38.69 nano M for ammonia, 6.44 nano M for phosphate and 49.52 nano M for silicate. Chlorophyll a was exceptionally high (up to 1323.7 nano kg/l), having an annual average of 107.5 nano g/l. The harbour water was relatively turbid most of the year The concentrations of dissolved oxygen revealed the alternation of good (5-10 ml/l) and relatively bad (1.9- 4 ml/l) aeration conditions. Consequently, low zooplankton abundance was found in the Dekhaila Harbour (annual average 22,640 ind./m3). Statistical analysis showed that the environmental factors controlling both phytoplankton and zooplankton biomass had different seasonal patterns.