Hydrology, hydrobiology and environmental pollution in the southern of Caspian Sea

The phytoplankton, zooplankton, Macrobenthos and ctenophore Mnemiopsis leidyi with Physico-chemical parameters and pollutants of water were investigated in the Caspian Sea during 2007-2008. The sample station located between 48° to 54° longitude and 36° to 39° latitude. The samples were gathered in four seasons and eight transects (half-line perpendicular to the coast) in Astara, Anzali, Sefidrud, Tonekabon, Noshahr, Babolsar, Amirabad and Turkmen. Sampling was done of 5, 10, 20, 50 and 100M depth of different layers. Nonparametric test and multivariate analysis (PCA) were used for statistical methods. Physico-chemical factors: The results showed that the changes of physico-chemical factors, includes: water temperature, salinity, organic nitrogen and inorganic nitrogen (ammonium) are most important than other factors. The lowest sea surface water temperature was recorded in winter (7.2°C) and highest in summer (29.8 °C) (p0.05). The lowest salinity was recorded in winter (10.42±0.14ppt) (p0.05). The most inorganic nitrogen was determined (ammonium ion: 40.8±2 µg.l^-1) in winter and the highest organic nitrogen (660.6±92 µg.l^-1) in summer (p0.05).The maximum concentrations of total nitrogen were measured at the near-shore stations (640.6±28 µg.l^-1). The annual average water transparency was 4.91±0.24 m and increased in away from the beach (p0.05). However, there was significantly in other groups (p0.05). The maximum of ctenophore abundance and biomass were belonged to the depth of low than 20m (p0.05). The maximum concentration values of OCPs in all groups in seawater were determined in winter (99%) (p0.05). The only DDT group in the seabed sediment had significant difference in different seasons (P0.05). In correlation matrix, the groups of Endosolfan and Drins in seawater and sediment were had equal variance and the changes were included. There was high correlation of between Endosulfan and Drin with DDT group in seawater and with Heptachlor group in the sediment of seabed. Surfactant: Mean surfactant concentration (LAS) between different seasons had significant difference (P0.05). Based on existing standards, Surfactant concentration in the southern Caspian Sea region was not critical.