On the view of the red tide phenomenon, ecological studies of phytoplankton community, in the Northern Waters of the Arabian Gulf

Abstract EN

Biological, chemical and ecological investigations on samples collected during May to October 2000 had been achieved at six sites of southern Iraqi area of the gulf.

No clear red tide had been detected, although some dinophyceae species were presented in some stations and occasions.The physico-chemical investigation of the south of Shatt Al-Arab River area showed marked increase in the salinity and decreased turbidity and chlorophyll a contents.

However, no marked fluctuation of water temperature had been detected.

No nitrite was detected at (Khur Al-Ummaia) and (Um Qasir) stations during August, while significant amount of nitrate was recorded during the same period.

High nitrate also recorded in north Shatt Al-Arab (Khalid Bridge and paper factory stations) compared to other stations.

Phosphate content had increased during August, and more values recorded at the Khur Zubair than that of the other stations.

Relatively, high amount of silicates was found during September mainly at Khalid Bridge.

The harmful red tide species Dinophysis caudata and Amphora coffeaeformis were found at some stations once during the whole investigated period.

Diatoms dominated during the investigation period.

No blue green and green algae had detected at the gulf site, e.g.

Khur Al-Ummaia, Um Qasir and Khur Zubair Stations.

Euglenophyceae species appeared at Khur Al-Ummaia Station.

Total of 75 species (41 genera) were identified in the six sites, of which there were 51 species (26 genera) of Bacillariophyceae, 5 species (5 genera) of Cyanophyceae, 8 species (5 genera) of Chlorophyceae, 2 species (2 genera) of Euglenophyceae, and 9 species (4 genera) of Dianophyceae.

Glenodinium borgei (Lemm.) Schill, and Glenodinium pulvisulcus (Ehr.) Stein appeared at Shatt Al-Arab River Stations (the estuary, Khalid Bridge and Paper factory) during the most of the sampling period.