Seasonal variation and vertical distribution of environmental parameters in the Iranian waters of the Persian Gulf (Hormozgan province)

Seasonal variation and vertical distribution of water temperature, pH, electrical conductivity, dissolved oxygen and chlorophyll-afrom the Iranian waters of Hormozgan province in the Persian Gulf were studied from February 2001 to February 2002. All parameters were measured by using CTD multiparameter probes at 30 sampling stations. Data obtain revealed that seasonal thermocline appears in the survey area during spring, extended in summer, diminishes in autumn and gradually eliminate during winter season. Variation in electrical conductivity follows the changes in winter temperature throughout the year except in winter. Dissolved oxygen was recorded to be higher in the depth layer of 10-25 meters and decreases by increasing depth. Vertical pH of water indicated a decreasing pattern from surface to bottom throughout the year, with highest decrease in autumn, when the dissolved oxygen decreases as well. The maximum concentration of chlorophyll-a was recorded at depth layers of 20-40m and 10-20m during first and second half of the year, respectively.