Evaluation of the Trophic Diatom Index for assessing water quality in River Gharasou, western Iran

Abstract

Water quality, diatom species composition and biomass estimates were performed in the Gharasou River in western Iran. Five sites along the River Gharasou were sampled every month from April to September 2005. Physical and chemical factors (pH, NO 3 -N, PO 4 -P, dissolved oxygen, total suspend solids, total dissolved solids, conductivity, turbidity, chemical oxygen demand and biological oxygen demand) were measured along with biological properties of the periphyton including biomass, ash-free dry mass, chlorophyll-a concentration and the taxonomic composition diatom assemblages. Information from the diatom assemblage was used to calculate the Trophic Diatom Index and biovolume. The TDI was significantly correlated with measures of human disturbance at the sites (e.g. PO 4 -P, NO 3 -N and dissolved oxygen) as well as to biomass measures (chlorophyll a, ash-free dry mass and biovolume). The sensitivity of the TDI and its component metrics to environmental stressors supports the use of this index for monitoring ecological conditions in streams in Iran and to aid diagnosis of the cause of their impairment.

Water Quality and Biotic Community of a Highland Stream under the Influence of a Eutrophic Fishpond

“…Similar diatom structures have been observed in other streams and rivers (ATAZADEH et al, 2007;LUKAVSKÝ et al, 2004). Generally, species belonging to genera such as Navicula and Nitzschia are predominant in the lower streams and thrive in nutrient-rich water.…”

A study of low-temperature and mountain epilithic diatom community in mountain stream at the Han River system, Korea

“…In the middle and lower parts of the streams, the abundance of saprophilous taxa (Kelly and Whitton 1995;Watanabe et al 2005) such as Nitzshcia amphibian, N. palea, and Navicula gregaria of Naviculaceae and Bacillariaceae increased. Generally, the relative frequency of taxa in Navicula and Nitzschia were higher in the lower regions than those in the upper regions (Atazadeh et al 2007;Kim et al 2009), which was thought to be due to pH and nutrient concentrations (Ginn et al 2007;Passy, 2007).…”

The effects of copper and zinc on biomass and taxonomic composition of algal periphyton communities from the River Gharasou, Western Iran

“…The Gharasou River in Western Iran suffers from heavy pollution by organic and inorganic toxicants due to the unregulated release of industrial and municipal wastes directly into the river (Atazadeh et al 2007). Effects of zinc on microbenthic communities have been observed at concentrations ranging from 0.05 mg l -1 to 2.5 mg l -1 Cairns 1992, Loez et al 1995) and effects of copper have been observed across a range of concentrations from 5 μg l -1 to 120 μg l -1 (Leland 1984, Real et al 2003.…”