Ecology of marine macroalgae in relation to pollution along the coast of Lebanon

Abstract

       Marine macroalgae were collected at six stations representing different pollution sources along the Mediterranean coast of Lebanon. Samples within 0.01 m² quadrates were collected at 1 to 2 m intervals along transects in the wave-wash zone of lime­stone platforms in spring and summer. The number of species, wet weight biomass, and environmental factors were recorded, and the taxonomic diversity determined according to D = (t - 1)/Ln B , where t = total number of taxa in a quadrate, and Ln = natural log of the wet weight biomass (g/m²).

       A total of 190 species were identified. A number of pollutant sources including chemical plant PO₄ enrichment, power plant thermal enrichment, sewage nutrient enrichment, and a possible variety of other urban pollutants resulted in reduced algal diversity over an extensive coastal zone of more than 50 km, a decrease in algal biomass, and a decrease in the percentage of Phaephyta and icrease in Chlorophyta species at polluted stations. The presence of Cystosiera spp., Carallina mediterranea, and Laurencia spp. indicate clean water, while Ulva spp., Enteromorpha spp., Colpomenia sinuosa, and Pterocladia pinnata appeared to thrive in      nutrient-enriched waters.