The listed plates were immersed vertically at 1.5 m depth in
Suez Gulf water during 2007 for 24 weeks. Water samples were
collected during the period of study from the surface water to
measure temperature, pH, DO, OOM and nutrients. The pH
was measured by a portable pH meter (Orion research model
210 digital). Dissolved oxygen was measured according to
Winkler method (1976). Oxidizable organic matter OOM
was determined according to the method reported by