Seasonal and spatial variation of hydrology and phytoplankton assemblages
in the Lebanese-Syrian coastal waters

• Marie Abboud Abi Saab^*, Marie-Thérèse Kassab ^*, Izdihar Ammar^**
• ^* National Center for Marines Sciences, P.O.Box 534, Batroun, Lebanon.
  Email: mabisaab@ cnrs.edu.lb
• ^** High Institute of Marine Research – Tishreen University – Lattakia – Syria.
  Email: tu-himr@scs-net.org

Abstract

In the frame work of a joint scientific program between Syria and Lebanon, hydrological and planktonic samples have been carried out, from 5 cruises between May 2002 and August 2003 in 6 offshore stations selected to cover the coastal waters of Lebano-syrian shoreline at the surface layer in order to compare the change across the south -north axis and at different seasons in the two coastal waters.

During this period, the surface temperature varied between 17. 4 and 30°C; no significant differences were detected among stations. The surface salinity varied between 39.608 psu in autumn and 38.3 in winter but in Syrian part salinity was reached 35psu in March and in summer results were comparable. The pH values varied between 8.1in winter and 8.3 in summer in both countries. Distribution of nitrogen and phosphorus were different in seasons and stations in both countries. Results showed that the samples collected during the 5 cruises differed both in general taxonomic representations of the microplankton components and in the distribution of species composition assemblages. Spatial variations showed that dominant species are mostly the same but differ in timing. Density variations in different offshore stations depend on the human continental activities and the dimensions and nature of continental shelf, which influenced the hydrology, and the population composition of marine waters.