Applicability of diatom based indices for water quality assessment in Iran ecosystems: case study Gorganrud subbasin (NE Iran)

Diatoms are one of the most important food resources in aquatic ecosystems extensively used in water quality assessments; however, use of diatom-based indices for water quality assessment is very scarce in Iran. In the present study applicability of diatom assemblage in monitoring ecological status in four tributaries of Gorganrud River, one of the main rivers in northeast Iran, evaluated. In this regard, water and diatom samples were collected monthly. In total ۷۳ diatom taxa belong to the ۳۰ genera identified. Achnanthidium minutissimum, A. gracillimum, Cymbella excisa, Diatoma moniliformis, Gomphonema olivaceum, Nitzschia dissipata and Rhoicosphenia abbreviata were the most dominant taxa in majority of the samples in all stations. The relationship between measured water quality indices (IRWQIsc and NSFWQI) and diatom index values (TDI and GDI) was assessed. Although results of the diatom indices and water quality indices were rather similar, however there were no significant correlations and relationships between indices. It seems further works are needed to clarify the usefulness of diatom indices in water quality assessments in Iran.

کلیدواژه ها:

diversity indices ، Golestan ، IRWQI ، NSFWQI ، TDI