Seasonal Variations of Chlorophyll a and Micro-Nutrients in Obhur Creek, Red Sea

The seasonal variations in chlorophyll a and micronutrients values were studied in Obhur creek near Jeddah, Saudi Arabia for one complete year (Oct. 1997-Oct. 1998). The chlorophyll a levels varied between 0.015 mg chl-a. m3 and 0.158 mg chl-a m3 showing prominent peaks in winter and autumn. Among nutrients, nitrate (average 1.12 µg-at / l) was present in higher concentrations than ammonia (average 0.39 µg-at / l) and nitrite, being the lowest (average 0.06 µg-at / l). The values of phosphate and silicate were also very low with average of 0.15 and 0.29 µg-at / l respectively. In general nutrients did not show any constant pattern of seasonality and were poor in concentration reflecting the oligotrophic conditions typical of the Red Sea.