biological Evaluation of Intertidal Zone of Mahshahr Ismaeili Estuary Using Structure of Large Population of Invertebrates Macrobenthic

Nowadays in water chemical quality determination and study over this matter, considering the presence of invertebrates macro benthic is one of the important and complementary elements diagnostic tests. With studying on changing population of invertebrates macro benthic and their variety, it is possible to evaluate the contamination of aqueous ecosystem especially estuaries. In this research comparison of the gained results from biological indices with physical and chemical tests, evaluation of Ismailee estuary’s (part of Moosa estuary) contamination was performed. For this purpose 5 stations were chosen and sampling was carried out in four different seasons. Also some indices related to water quality and sediment rate for different objects such as DO, EC, water temperature, pH, turbidity, GSA and TOM were tested and measured. According to the achieved results there were found 4 identical groups of macro benthic which include 44 species in that study area. Based on this research the highest percentage belongs to Polycheata with 35.77%, then Bivalvia with 33.15%, abdomen end of the Gastropoda with 19.76% and Crustacea with 11.32%. The average of studied density of Macrobenthose per square meter of bed area was 550 individuals. That means the density of these creators is low. In order to identify the contamination rate of the ecological condition of this area, Welch model was applied. Calculating the gained amount of Shanon Index with presented Welch index shows that the studied area has moderate range of contamination.