A new diatom index to assess ecological quality of running waters: a case study of water bodies in western Anatolia

Abstract

Diatoms are an important part of aquatic biodiversity and the main component of phytobenthos. They play a key role in aquatic ecosystems and indicate water quality. The European Union Water Framework Directive requires that phytobenthos be used for the ecological quality assessment of water. This study evaluated the ecological status of various watercourses in the western Mediterranean basin of Turkey using a multivariate approach and presents a new trophic index Turkey (TIT) based on diatom assemblages. Twenty-five running water bodies were seasonally monitored for biological and physicochemical analyses from summer 2014 to summer 2015. A total of 102 species belonging to 22 genera were recorded. Cymbella excisa Ku¨tzing, Gomphonella parvula (Ku¨tzing) Rabenhorst, Ulnaria ulna (Nitzsch) Compe`re, and Cocconeis communis f. placentula (Ehrenberg) Chmielevski were the most commonly found species. A canonical correspondence analysis was used to examine the relationship between species and environmental factors. The most effective explanatory factors, including nitrate nitrogen, electrical conductivity, altitude, total nitrogen, orthophosphate, and calcium carbonate significantly influenced the ecological preferences of diatom species in the ecosystems. TIT values ranged between 1.53 in Kaya creek and 2.73 in Dalaman stream (A8). Ecological status of water bodies was assessed using an ecological quality ratio based on trophic index Turkey (EQR-TIT) for each of the stations. EQR-TIT ranged from 0.44 in Dalaman stream (A8) to 0.99 in Kocabu¨k creek during the study period. TIT had a high correlation coefficient (R 2 = 0.77) with log total phosphorus and may be an appropriate diatom metric to assess the ecological status of water bodies.

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

“…Relatively high nutrient values in the studied sampling stations in the Araban-Yavuzeli catchment were a consequence of the pressure of agricultural activities, discharge of domestic wastewaters with insufficient treatment facilities, and runoff from fertilized agricultural soils. This kind of pollution problem was also proposed in different ecoregions (Delgado and Pardo, 2014;Mangadze et al, 2015;Toudjani et al, 2017). Another important pollution source was manure thrown into agricultural lands that leaked into receiving water bodies via irrigation and was transferred with soil erosion.…”

“…Diatom metrics in Europe (Cemagref, 1982;Rott et al, 1999;Dell'Uomo, 2004;Kelly et al, 2008) have been successfully used for the assessment of water ecological quality. However, the available European diatom indices have not been used efficiently in the Mediterranean region for the interpretation of water quality (Toudjani et al, 2017;Lazaridou et al, 2018). This can be due to the impact of ecoregional factors (e.g., geology, climate, land use, and anthropogenic activities) on the optimum and tolerance of diatom assemblages (Soininen, 2007;Toudjani et al, 2017).…”

The Use of Phytobenthos for the Ecological Status Assessment in Upper Sakarya Basin, Turkey

“…Some studies were carried out in order to classify the water quality by using diatom indices in Turkey (Kalyoncu et al, 2009;Kıvrak et al, 2012; Morkoyunlu Yüce and Gönülol, 2016; Atıcı et al, 2018). In addition, other studies are also available which evaluate the phytobenthos for each river basin (Demir et al, 2017;Toudjani et al, 2017).…”

Benthic Diatoms in River Biomonitoring—Present and Future Perspectives within the Water Framework Directive

“…Soon after the implementation of WFD, its significance prompted countries outside Europe to consider adopting similar legislations and assessment methods. Neighboring countries such as Turkey have developed their own indices for biomonitoring, considering them as more accurate for their ecoregion (Turkey trophic index) [89]. In North America, the US is using biomonitoring through the Clean Water Act, whereas Canada has taken initiatives to implement a more organized framework to bioassessment methods already sporadically applied [90].…”