Abboud Abi Saab, Marie National Council for Scientific Research - National Center for Marine Sciences, Lebanon , Fakhri, Milad National Council for Scientific Research - National Center for Marine Sciences, Lebanon , Sadek, Eliane Lebanese University - faculty of Agronomy, Lebanon , Matar, Nada National Council for Scientific Research - National Center for Marine Sciences, Lebanon

An estimate of the environmental status of Lebanese littoral waters using nutrients and Chlorophyll-A as indicators

34214

In the aim to estimate the environmental status and to detect the signs of eutrophication in the Lebanese coastal waters using nutrients and chlorophyll-a as indicators, surface water analysis was run monthly for a period of 12 months, from March 2005 till February 2006, along 18 stations that extend from Tripoli in the north. to Naqoura in the south. Physico-chemical and biological parameters of the water samples were also studied. During this period, the temperature followed its normal cycle usually noted in the Lebanese waters; whereas salinity varied spatially and temporally pr esenting sometimes low values due to the rivers inputs. Significant fluctuations of nutrients and chI-a concentrations were observed in most of the stations and during year cycle. High levels of nitrate (30.68 mu M/L) were observed at stations located near river and sewers, whereas high levels of orthophosphates (5.17 mu M/L) were detected in zones around the Selaata factory. However the high values of phosphate and nitrate at some sites have caused an important increase in the primary production as shown by high chlorophyll-a concentrations (15.02 mg/m3) . According to the results and in relation with continental input and the first trophic level which react to this man-made disturbance, stations can be divided into 5 categories: reference (mean values of P-P04 0.15 mu M/L, N-N02 0.05 mu M/L , N-N0 3 0.34 mu M/L and chI-a 0.12 mg/m3), slightly enriched, enriched indirectly by river input or phosphorus input, directly by river input and directly by sewage input stations. Three stations are classified as moderately eutrophied whereas the other stations present a weak eutrophication. The principal component analysis confirms this result by showing the factors influencing on the various parameters and determining the existing correlation among them. Consequently , the concentrations of nutrients and chlorophyll-a biomass can be considered good indicators to assess the environmental status of the sites.

43

Lebanese coastal waters , chlorophyll , a , nutrients , eutrophication , bio logical indicators , environmental status assessment

Lebanese Science Journal

60