Study of horizontal and vertical distribution of physic- chemical parameters and chlorophyll a in Hormoz Strait

Subject Areas : Marine Biology

L. Bahrami Samani ¹ , M. Ebrahimi ² , M. Ghorbanli ³

1 - Marine Biolog Dep, Faculty of Marine Science and Technology, North Tehran Branch, Islamic Azad University
2 - Iranian Fisheries Research Organization, Persian Gulf and Oman Sea Ecology Research Center
3 - Islamic Azad University, Gorgan Branch

Received: 2010-09-26 Accepted : 2010-11-24 Published : 2011-03-19

Keywords: chlorophyll a, Persian Gulf, physico- chemical parameters, surface cantor, vertical profile, Strait of Hormoz, Gulf of Oman,

Abstract :

In order to access the process of horizontal and vertical change in physic- chemical parameters and chl.a in the coastlines of Hormozegan Province from the Jask region to Bandar Lengeh in the area of 54˚ to 57˚ and 49 minutes along the east  , 34 stations were selected .The sampling operation was done in February of 2008 by using R/V Ferdous 1 with the assistance of the Ecology Institute of the Persia Gulf and the Sea of Oman. The  results of the horizontal distribution of salinity and density indicated that the parameters from the east to the west have increased . The salinity in the region of Bandar Jask 36.7 and around KishIsland it has reached 37.9 (ppt). In the Jask area , density has reached 24.8 and around Kish area it has increased to 26.2 g/cm3 . The salinity and density increased from surface to depth.But this increase had more fluctuations in the areas of west of Straight of Hormoz (Persian Gulf) compared to the areas from east to the west and from the surface to the depth where it actually reduces . The results from the horizontal distribution of chl.a indicated that  in this month, the amount of chl.a in the region of Bandar Abbass and the Strait of Hormoz because of Plankton  blooming is relatively more that the east and west of the Strait of Hormoz. In addition to that , the vertical changes of chl.a indicated that its amount in the coastlines where the plankton bloom was visible , was reduced from the surface to the depth , but in the marine stations the highest amount of it was in the 10-20 meter layers of depth .The result from the study of water`s turbidity indicated the process of changes in the water's turbidity , especially in the surface layers follows the chl.a changes . Also , the study of the horizontal distribution of the water's turbidity in the surface of the regions under study indicated that the western regions of the Strait of Hormoz enjoyed or had the highest amount of turbidity and its reason was its being shallow and effects of mangro Forests. The results indicated that there was a direct correlation between the horizontal and vertical distribution and the amount of chl.a and the disolved oxygen. It means that as the chl.a increased , the oxygen also went up and as it went down , the oxygen went down too. The results of the statistical study between chl.a and desolved oxygen in the 3 zone of the study indicated that in the northern region of the Strait of Hormoz , the correlation index between the two parameters was 0.9 and in the east and west it was 0.7 .  The amount of EC from the surface to the depth was reduced and its process of changes followed almost the process of changes in the temperature while the amount of desolved oxygen in the region of the Strait of Hormoz were more than eastern and western stations.