The Trophic Diatom Index: a new index for monitoring eutrophication in rivers

Abstract

A index for monitoring the trophic status of rivers based on diatom composition ('trophic diatom index', TDI) has been developed, in response to the National Rivers Authority (England & Wales)'s needs under the terms of the Urban Wastewater Treatment Directive of the European Community. The index is based on a suite of 86 taxa selected both for their indicator value and ease of identification. When tested on a dataset from 70 sites free of significant organic pollution, this index was more highly correlated with aqueous P concentrations than previous diatom indices. However, where there was heavy organic pollution, it was difficult to separate the effects of eutrophication from other effects. For this reason, the value of TDI is supplemented by an indication of the proportion of the sample that is composed of taxa tolerant to organic pollution.The index was tested on the R. Browney, N-E. England, above and below a major sewage discharge. TDI values indicated that the effect of inorganic nutrients on the river downstream of the discharge was slight as the river was already nutrient-rich, but there was a large increase in the proportion of organic pollution-tolerant taxa. This indicates that the river was already so eutrophic upstream of the discharge that tertiary treatment to remove P would not be effective unless other aspects of the discharge were also improved.

Use of benthic diatom indices for assessing ecological status of the Sai Gon river, Vietnam

“…The TDI index was first developed by Kelly and Whitton (1995) [3] and later revised by Kelly, et al (2001) [22]. This index was calculated by using species composition and abundance of each diatom species.…”

“…This index was calculated by using species composition and abundance of each diatom species. Each diatom species was given a sensitivity value from 1 to 5, where 1 indicates species that favour very low nutrients and 5 very high nutrients, and an indicator value from 1 to 3, where 3 means a species is a good indicator of nutrient sensitivity and 1 means that it is a poor indicator [3,22]. Values were originally determined for each diatom species/genus based on the orthophosphate concentrations, where taxa are most abundant.…”

“…Many diatom indices have been developed and applied for the classification water quality. As a multi-metric approach, the TDI originally developed by Kelly and Whitton (1995) [3], and the BDI developed by Lenoir and Coste (1996) [4], were commonly used in monitoring aquatic conditions. The TDI and BDI indices have been applied in several countries for assessing water quality.…”

Uncertainty in Diatom Assessment: Sampling, Identification and Counting Variation

“…The relative diatom counts were ordinated by redundancy analysis (RDA) with the program (Kelly & Whitton, 1995) %PT % pollution tolerant taxa (Kelly & Whitton, 1995) EPI-D Pollution metric based on diatoms (Dell'Uomo, 1996) ROTT Trophic metric (Rott et al, 1999) IDG Generic Diatom Metric (Lecointe et al, 2003) CEE Commission for Economical Community metric (Descy & Coste, 1991) IBD Biological Diatom Metric (Prygiel & Coste, 1999) IDAP Indice Diatomique Artois Picardie (Lecointe et al, 2003) 249 CANOCO 4.5 (Ter Braak & Sˆmilauer, 2002). The data analysis is fully described by Verdonschot & Ter Braak (1994 Verdonschot & Ter Braak (1994).…”

Sampler collection gadget for epilithic diatoms

“…Epilithic diatoms are recognized worldwide as one of the most fitting biological components for water quality assessment, due to their constant presence along the aquatic system, and also because they give a quick response to environmental changes (Lowe and Gale, 1980;Watanabe, 1985;Schoeman and Haworth, 1986;Coste et al, 1991;Pryngiel, 1991;Round, 1991;1993;Kelly and Whitton, 1995;Descy and Ector, 1999;Rott, 1991,1996;Kelly, 2002;Lobo et al, 2002;Lobo et al 2004;Salomoni, 2004).…”