Bioassessing ecological status of surface waters in the Araban-Yavuzeli catchment (Turkey): application of diatom indices

Abstract

Within the scope of the European Union Water Framework Directive, diatom assemblages as biological quality components were used to evaluate the ecological status of 12 surface waters in the Araban-Yavuzeli catchment between October 2013 and October 2014. A total of 75 diatom species were identified during the study period. Amphora ovalis, Denticula elegans, Gomphonema parvulum, Gomphonema truncatum, and Navicula cryptocephala were commonly observed. The relationship between diatom assemblages and environmental factors was assessed by canonical correspondence analysis and weighted average regression. Dissolved oxygen, temperature, nitrate, biological oxygen demand, lead, and copper played significant roles in the distribution and composition of diatom assemblages (P < 0.05). The ecological status of the stations in Araban and Yavuzeli was characterized using the trophic index-Turkey (TIT), trophic index (TI), and eutrophication and/or pollution index-diatom (EPI-D) indices. According to the TIT, Ardıl Creek1 had very good ecological conditions and was characterized by the occurrence of pollution-sensitive diatom taxa (e.g., Cymbella affinis, Encyonema silesiacum, Navicula radiosa), indicated by multivariate analyses. The significant positive correlation of the TIT (P < 0.01, r = 0.789) with logPO 4 indicated that TIT may be used as an appropriate diatom metric to assess the ecological status of surface waters in the Araban-Yavuzeli catchment.

Using diatom indices to estimate the ecological status of minimally disturbed rivers of the Sakarya River Basin (Türkiye)

“…In some studies with rivers from different basins that were monitored using diatom indices, the TIT gave compatible results with environmental parameters and indicator species (Çelekli & Bilgi, 2019;Çelekli, Lekesiz, & Yavuzatmaca, 2021).…”

Eco‐assessment of Değirmendere and Bulaklı streams using diatom indices from different ecoregions

“…Pollution‐sensitive species (e.g., A. bryophila , A. minutissimum , E. minutum , and C. excisa showed close relationships with especially D1 and D2 stations of Değirmendere stream (Figure 5), which had TP optima levels lower than the 25th percentile (Figure 7). These species were also found in semi‐arid regions, where they had similar phosphorous optima (Çelekli & Arslanargun, 2019; Çelekli & Bilgi, 2019). These pollution‐sensitive species having TP optima values are higher than those of Austria (Binder, 2001) and are lower than that of Australia (Oeding & Taffs, 2017) due to the effects of different ecoregions on different ecosystems.…”

“…Among the European diatom indices, IPS having more diatom species has been commonly used to evaluate the surface waters of the Eastern Mediterranean Region such as Cyprus (Cantonati et al, 2020; Pissaridou et al, 2021) and Greece (Karaouzas et al, 2019). The European indices cannot efficiently adapt to the particular hydrological and climatic conditions of the Eastern Mediterranean Region (Çelekli et al, 2018; Çelekli & Bilgi, 2019; Çelekli & Lekesiz, 2020; Lazaridou et al, 2018) because ecoregional factors influence the trophic weight of diatom taxa. The species list of TIT did not include all of the taxa found in the streams and so the revision of the species list is necessary for better the bioassessment of streams.…”

Bioassessment of water quality of surface waters using diatom metrics

“…Research dealing with bioindicators has gained momentum to understand the responses of species to stressors and such kinds of studies indicate an uptrend. Many bioassessment studies deal with diatom metrics have been carried out in Europe, Asia, and America (e.g., Lavoie et al, 2009;Wachnicka et al, 2011;Bere, 2016;Vilmi et al, 2016;Xue et al, 2019;Szczepocka et al, 2019;Tapolczai et al, 2019;Edwards et al, 2020), while there are a few studies in Turkey, e.g., in the West Mediterranean basin (Çelekli and Lekesiz, 2020), Aras basin (Çelekli et al, 2019a), Sakarya basin (Çetin and Demir, 2019) and the southeast of Anatolia (Çelekli and Arslanargun, 2019;Çelekli and Bilgi, 2019;Çelekli and Kapı, 2019). Results indicated that the number of studies related to diatom indices based on the ecoregion should increase to obtain clearer and more accurate results in Turkey.…”

“…A recently developed diatom index called TIT (Trophic Index Turkey) (Çelekli et al, 2019b) was the first diatom index in Turkey. The suitability of this index has been tested in different geographical and ecological regions of Turkey; for example, the freshwaters of the Western Anatolian basin (Toudjani et al, 2017), the North Aegean basin (Çelekli et al, 2018), Aras river basin (Çelekli et al, 2019a), the West Mediterranean basin (Çelekli and Lekesiz, 2020), and the southeast of Anatolia (Çelekli and Kapı, 2019;Çelekli and Arslanargun, 2019;Çelekli and Bilgi, 2019). Results indicated that TIT is an accurate diatom index when compared with the other diatom indices used to assess the ecological status of lotic ecosystems because of ecoregional environmental factors on the trophic weight of diatom taxa in Turkey (Lobo et al, 2004;Çelekli and Kapı, 2019).…”