Seasonal variations of chlorophyll-A, dissolved oxygen and turbidity in the southern Caspian Sea (Noshahr coast)

Seasonal variability of different parameters of the water column including chlorophyll-a, dissolved oxygen and turbidity in Noshahr region in Mazandaran province based on measurements using CTD device taken during different seasons of 1397 are investigated. According to the results, maximum chlorophyll-a during the spring in offshore area is below the mixed layer at the depth of 20 (m), during the summer with the lowest concentration among all the seasons is inside the mixed layer at the depth of 20 (m) in offshore area and during the fall and the winter the highest concentration of chlorophyll-a is observed near the coast. Maximum dissolved oxygen during the spring is located at the depth of about 20 (m), in the spring in the offshore is at the depth of 40 (m) and during the fall and winter is observed with maximum values near the surface and the lowest values near the bottom. Maximum turbidity is observed in all seasons near the shore at the depth of 5 m and the maximum values of the turbidity are found during the cold seasons. Zero values of the turbidity during the winter is observed inside the mixed layer, while during the fall and the summer is below the mixed layer and in the spring is found in the deep layer.