Seasonal dynamics and diversity of phytoplankton in Sharm Yanbu lagoon, Red Sea, Saudi Arabia

الملخص EN

Yanbu is considered one of the most important industrial and touristic areas on Saudi coast of the eastern side of the Red Sea.

It is a developing and expanding city with modern facilities and industries which can affect the coastal environment and influence the qualitative and quantitative dynamics of the phytoplankton community.

The present study was carried seasonally on the species composition and abundance of phytoplankton concurrently with the surrounding physico-chemical conditions of Sharm Yanbu lagoon.

The results revealed that water temperature ranged 22.00o C and 33.30o C, and chlorophyll a concentration of 0.07−2.20 µg.L-1.

A total of 168 phytoplankton species were identified, including 94 Bacillariophyceae, 69 Dinophyceae, 3 Cyanophyceae, 1 Chlorophyceae and 1 Mediophyceae.

Cell abundance varied from 2.34×103 to 12.07×103 cells.L-1, with the highest count occurred in spring and the lowest in winter.

Bacillariophyceae contributed (54.95%), followed by Dinophyceae (40.07%), Cyanophyceae (3.79%), Chlorophyceae (0.60%) and Mediophyceae (0.60%) to total of phytoplankton.

Among Bacillariophyceae, the pennate forms constituted 32.34% and centric 22.28%.

Phytoplankton exhibited positive correlation with chlorophyll a in spring, summer and autumn (r = 0.64, r = 0.59 and r = 0.66), respectively.