Relationships Among Epipelic Diatom Taxa, Bacterial Abundances and Water Quality in a Highly Polluted Stream Catchment, Bursa – Turkey

Abstract

Nilüfer Stream is an important water source in the industrial and metropolitan city of Bursa, Turkey. The stream catchment has been influenced by high human impact. The downstream receives sewage water from households and industry, whereas the headwater of the stream has a source of high-quality drinkable water. In this paper, abundances of epipelic diatom taxa, faecal coliforms (FC), total coliforms (TC) and total bacteria (TB) were studied in relation to measured environmental variables (T, pH, DO, BOD(5), EC, TDS) for the period July 1997 to June 1998 at six stations in the heavily polluted Nilüfer Stream catchment. It is observed that the physicochemical variables and bacterial abundances varied seasonally at all stations, and the level of pollution reached at its highest point in the summer. The results of Kruskal-Wallis and one-way ANOVA indicated that DO gradually decreased, whereas BOD(5), EC, TDS, TB, FC and TC gradually increased from upstream to downstream. The ordination method of Principal Component Analysis (PCA) was carried out for both biologic and physicochemical variables, and the results were supported by the former statistical procedures. The frequency of occurrence of dominant diatoms was examined in relation to the spatial variations in chemical constituents. Both diatoms and bacteria showed strong correlations with the measured physicochemical variables. In Canonical Correlation Analysis (CANCORR) measures of bacterial abundances also displayed strong correlations with abundances of 11 diatom taxa. The results showed that the stream catchment is polluted gradually from upstream to downstream. In addition, pollution load in the stream catchment has been gradually increased, compared with recent years. Urbanisation and industrialisation of the city have affected increasing pollution in Nilüfer Stream. The results also indicated that diatoms are not affected by environmental variables such as bacteria. Bacteria are more sensitive to organic pollution, while diatoms are indicators of different environmental conditions.

A comparison between biotic indices and predictive models in stream water quality assessment based on benthic diatom communities

“…The DA results confirmed the sensitivity of diatoms to organic pollution, as indicated in many other studies (e.g., Van Dam et al, 1994;Rimet et al, 2005;Dere et al, 2006;Blanco et al, 2007) and also to nutrient load (e.g., Weckströ m and Juggins, 2005;Dela-Cruz et al, 2006;Potapova and Charles, 2007;Blanco et al, 2007) with all variables in the category of nutrients and organic contamination being related to the indices and model outputs at least once. Among those, nitrates, nitrites, phosphates, water oxygenation and conductivity were the variables more often chosen by the DA.…”

Relationships between epipelic diatoms, aquatic macrophytes, and water quality in Akarçay Stream, Afyonkarahisar, Turkey

“…Similar reports on N. palea were noted by a number of researchers (Gómez and Licursi 2001, Soininen 2002, Bellinger et al 2006, Szczepocka and Szulc 2009). This species is also commonly found in polluted Turkish rivers (Gürbüz and Kivrak 2002, Dere et al 2006, Kalyoncu et al 2009, Solak 2011. In the CCA ordination diagram, Navicula cryptocephala was placed near axis 1 and axis 2 in the positive part of the first axis near TDS and the NO2-N vector, and these species were established as indicator species of α-mesosaprobous or oligo-to eutraphentic (hypereutraphentic) environments, according to Van Dam et al (1994).…”

“…They are abundant in eutrophic habitats worldwide (Kwandrans et al 1998, Soininen 2002, Szczepocka and Szulc 2009. These species were also found in eutrophic habitats in rivers in Turkey (Gürbüz and Kivrak 2002, Dere et al 2006, Kalyoncu et al 2009). …”

“…In the CCA ordination diagram, Navicula cryptocephala was placed near axis 1 and axis 2 in the positive part of the first axis near TDS and the NO2-N vector, and these species were established as indicator species of α-mesosaprobous or oligo-to eutraphentic (hypereutraphentic) environments, according to Van Dam et al (1994). Navicula species are abundant in many rivers and lakes throughout Turkey (Soylu and Gönülol 2005, Dere et al 2006, Kalyoncu et al 2009, Solak 2011. Nather Khan (1990) explained that this species of Navicula was common and abundant in both organically enriched and non-enriched areas.…”

“…In general, physical and chemical parameters are used exclusively to determinate water quality in Turkey. Studies regarding biological indicators in this region are rare (Gürbüz and Kivrak 2002, Dere et al 2006, Serteser et al 2008, which is why this study is unique.…”