The application and testing of diatom-based indices of stream water quality in Chinhoyi Town, Zimbabwe

Abstract

Aquatic ecosystem biomonitoring tools are largely lacking for many developing countries, resulting in adoption of tools developed from other countries/regions. In many instances, however, the applicability of adopted tools to the new system has not been explicitly evaluated. The objective of this study was to test the applicability of foreign diatom-based water quality assessment indices to urban streams in Zimbabwe, with the view of stimulating research to develop improved approaches for assessing ecological integrity of lotic systems in the country. The study evaluated the relationship between measured water quality variables and diatom index scores. The study found a high degree of concordance between water quality variables and diatom index scores. Thus, the indices proved useful in providing an indication of the quality of the investigated waters. This could be attributed to the occurrence of many widely distributed diatom species that have similar environmental tolerances to those recorded elsewhere. Diatom indices which exhibited consistent classifications and strong correlations with water quality variables such as Trophic Index, Saprobic Index, Pampean Diatom Index, Biological Index of Water Quality and Leclercq Index are recommended for use in the country. However, ecological requirements of some diatom species from Zimbabwe need to be clarified and incorporated in a diatom-based water quality assessment protocol unique to the country.

Assessment of water quality based on diatom indices in a small temperate river system, Kowie River, South Africa

“…Lobo et al, 2004;Ndiritu et al, 2006;Taylor et al, 2007;Bellinger et al, 2009;Bere et al, 2014, Hlúbiková et al, 2014Tan et al, 2014a, b), the current study indicates that benthic diatom communities can be a useful tool for water quality monitoring since the diatom communities recorded changed in response to land-use patterns and anthropogenic activities. Most of the sites along the length of the river, excluding the upstream sites, were subjected to point-source pollution from the catchment, which resulted in the species distribution being strongly biased towards cosmopolitan diatom species (e.g.…”

“…Diatoms are the main primary producers and chemical modulators in freshwater aquatic ecosystems (Wu et al, 2012;Bere et al, 2014;Dalu et al, 2014a, b;Mangadze et al, 2015) and represent an important carbon and energy source for secondary consumers (Tan et al, 2014a;Venkatachalapathy and Karthikeyan, 2015). Because diatoms are very sensitive to environmental change and/or disturbances such as eutrophication, acidification, land use and pollution, they are considered to be powerful indicators of water quality in freshwater systems (Harding et al, 2005;Taylor et al, 2007a;Walsh and Wepener, 2009;Bere and Tundisi, 2010a;Wu et al, 2012;Rimet et al, 2015).…”

“…Moreover diatoms have distinct ecological tolerances (Bahls, 1993) and short generation time (Zalack et al, 2010;Tan et al, 2014b), making them suitable indicator organisms for water quality changes over short time scales. Diatoms have been employed as water quality indicators in Europe (Kelly et al 1998;Prygiel et al, 1999), North America (Stevenson and Pan, 1999;Lowe and Pan, 1996;Winter and Duthie, 2000;Lavoie et al, 2006Lavoie et al, , 2014, South America (Lobo et al, 1996;Bere and Tundisi, 2011), Australia (Chessman et al, 1999;John, 2000), Asia (Lobo et al, 1995;Rothfritz et al, 1997) and, to a lesser extent, Africa (Bellinger et al, 2006;Ndirutu et al, 2006;Taylor et al, 2007a, b;Bere et al, 2014;Mangadze et al, 2015).…”

“…Most of the indices employed are based on Zelinka and Marvan's (1961) approach, which considers weighted averages of taxa's sensitivity to nutrients and organic degradation, as well as pH and salinity (Taylor et al, 2007b;Almeida et al, 2014;Bere et al, 2014;Hlúbiková et al, 2014). The simplest indices comprise a single metric which is used to indicate the degree of impact (Taylor et al, 2007a;Schowe and Harding, 2014).…”

Microbial mats as shelter microhabitat for amphipods in an intermittent karstic spring

“…N. palea was also found in tufa-forming microbial mats from the Harz Mountains karst streams in Germany (Arp et al, 2010). Due to its exceptional tolerance to organic pollution and heavy metals (Palmer, 1969), biomass increase of N. palea is an indication of anthropogenic pollution (Tornés et al, 2007;Bere et al, 2014). The low abundance of N. palea recorded in Krčić Spring during the study period suggests minimum anthropogenic pressure on the stream.…”