Investigation of physicochemical factors, chl-a and primary production in Mahshahr Creeks (Northwest Persian Gulf)

Abstract The study on physicochemical factors and primary production of the aquatic ecosystems is important to know the characteristics of the environment and capacity of recharge. Mahshahr Creeks are the most important creeks in the Northwest Persian Gulf, Iran. In this study, variations in physicochemical factors, chl-a, and primary production in creeks of Mahshahr, Zangi, and Moussa were evaluated for 2 months of every season of 2014. The following variables were analyzed: nitrate, phosphate, nitrite, silicate, temperature, salinity, DO, pH, conductivity, turbidity, light, chl-a, primary production and phytoplankton abundance. The maximum amount of chl-a (1.6 mg m-3) was observed in Moussa Creek in April while the minimum amount (0.1 mg m-3) was seen in Moussa in July. The highest (1.19 gc m-2 day-1) and lowest (0.1gc m-2 day-1) amount of primary production were observed at the entrance of Moussa Creek in April and in Zangi Creek in November, respectively. The maximum and minimum abundance of phytoplankton was observed in April and October, respectively in all study areas. The results of correlation test between the studied factors revealed that primary production has a significant relationship with nitrite, chl-a, phytoplankton abundance and light. Primary production in these creeks is relatively high in April and is attributed to the uptake of nutrients including nitrate and phosphate from shallow waters entering these creeks, sufficient light and suitable temperature, but in other months the production is low.