Local factors or altitudinal gradient: which one is effective on diatom communities and ecological status in the 23 lentic systems of the Sakarya Basin (Türkiye)?

In the 23 lentic systems of the Sakarya Basin, littoral diatoms and environmental variables were assessed with the samples collected in the spring, summer, and fall of 2018 to determine the effect of altitude or local factors on diatom assemblages. A total of 210 diatom taxa in 63 genera were identified during the studied period. Both the distribution of indicator species and the species composition were affected by pH, electrical conductivity, alkalinity, total organic carbon, total nitrogen, and total phosphorus. Especially low alkalinity was found to be effective in the distribution of high-altitude optima species. Close geographical location was also important in shaping species composition. Although the species richness and diversity of lentic systems on > 1600 m a.s.l. were higher than those in lower altitudes, pH and total phosphorus were the determinant factors. On the other hand, altitude indirectly affected all these factors by causing habitat diversity. The Leclercq and Maquet Diatomic Index showed a higher correlation with total nitrogen, total organic carbon, and total phosphorus. This index was more effective in determining the ecological status of 23 lentic systems. Altitude has also an indirect effect on the ecological status of these systems by restricting anthropogenic pressure such as total phosphorus.

The distribution of diatom assemblages with the effects of environmental parameters and ecological status assessment based on diatom indices in the lentic systems of the Akarçay and Asi Basins (Türkiye).

In order to detect the effects of different stressors on the littoral diatom assemblages and biodiversity of the lentic systems in two different basins in Türkiye, 15 lentic systems in the Akarçay and Asi basins were sampled three times (spring, summer, and fall) for littoral diatoms and environmental variables. The biological assessment of these sites was also evaluated using 9 different river and lake diatom indices. Based on the total phosphorus (TP), total nitrogen (TN), electrical conductivity (EC), salinity (SAL) values, and dominant diatom species, three lentic systems in Akarçay Basin (Lake Eber, 26 Agustos Pond, and Lake Karamik) were more eutrophic and under the pressure of anthropogenic and climatic (precipitation) stressors. Trophic diatom index for lakes (TDIL) showed a higher correlation with TN and TP and was the most effective index in explaining ecological quality in 15 lentic systems. The species richness of diatoms was also negatively affected by EC and SAL values. The lentic systems of the two basins were separated from each other based on the species composition and the distribution of the dominant species with the effect of altitude (ALT). Considering the distribution of diatom assemblage of the lentic systems in these two basins, anthropogenic, climatic, and geographical factors have become prominent to shape the diatom community structure.

Eco-assessment of streams of Konya closed river basin (Turkey) using various ecoregional diatom indices.

Ecological assessment of freshwater ecosystems based on diatom metrics is an important issue for attaining environmental sustainability. The present study aimed to evaluate differences in the diatom-stressor relationship in relatively least disturbed streams in the Konya closed river basin using multivariate analyses and to bio-assess streams by the application of different ecoregional diatom indices. Cocconeis euglypta, Cymbella excisa, Cocconeis placentula, and Achnanthidium minutissimum are the most contributing species to the dissimilarity of sampling stations between rainy (spring) and dry (summer and fall) seasons and also between altitude (A2 800- < 1600 m and A3 ≥ 1600 m) groups. The first two axes of canonical correspondence analysis revealed a significant (82.8%) relationship between diatom species and stressors. Diatom species displayed distinct responses to environmental variables (electrical conductivity, Ni, Cu, B, and altitude) playing important roles on the distribution of species. Diatom indices indicate different ecological statuses of stations, from bad to high. European diatom indices except Duero Diatom Index (DDI) and Trophic Diatom Index (TDI) showed good responses to the eco-assessment of streams and indicated high ecological status for the least disturbed sampling stations symbolized as S16, S20, S24, S25, S27-29, S37, and S39. These results were also supported by abiotic evaluation. Although TIT was more competitive in the bio-assessment of streams among diatom indices, it is necessary to increase its species list by determining their trophic weights in future studies. Therefore, the use of ecoregion-specific diatom indices is suggested along with increasing the number of used species to correctly interpret the water quality.

Eco-assessment of least disturbed areas of the Antalya River basin: application of diatom indices from different ecoregions.

Biomonitoring of least disturbed areas is a crucial issue to accurately assess the ecological status of surface waters and ensure their sustainability. Diatom metrics are important tools for the assessment of environmental conditions of lotic ecosystems to achieve environmental sustainability. The present study was aimed to evaluate the ecological status of least disturbed areas in the Antalya River basin (Turkey) using diatom indices developed from different ecoregion. Diatom species such as Cymbella excisa, Achnanthidium minutissimum, Cocconeis euglypta, and Cocconeis placentula were the most contributing species to the dissimilarity of sampling stations between rainy and dry seasons. The first two axes of canonical correspondence analysis (CCA) elucidated a strong (86%) correlation between diatom taxa and stressors. Results of the Monte Carlo permutation test indicated that total phosphorus (TP), water temperature, Tin (Sn), total organic carbon, zinc, and pH are significantly influential ecological factors on the distribution of diatom taxa among sampling stations. The Spearman correlation rank test indicated that diatom indices had significant positive and negative correlations with TP gradient. Results revealed that diatom indices developed from different ecoregions have different scores for the eco-assessment of similar sampling stations. European diatom indices mostly showed similar behavior in the bioassessment of the ecological status of rivers in the Antalya region compared to the different ecoregion. Among European diatom indices, TIT was more competitive and could give better results in the bio-evaluation of rivers in the Antalya River basin. Using diatom indices developed from different ecoregions may lead to an erroneous assessment of water quality. Accordingly, ecoregional specific diatom metrics are needed to accurately determine the surface water quality. Eco-assessment of least disturbed areas of the Antalya River basin: application of diatom indices from different ecoregions: Abuzer Çelekli, Ömer Lekesiz, Tolga Çetin.

Testing the performance of European diatom indices for evaluating the ecological status in the Kizilirmak basin, Turkey: flowing waters.

The Kizilirmak River is the longest river (1.355 km) in Turkey and flows into the Black Sea. Main pressures in the basin are waste water discharges, widespread agriculture, livestock activities, and excessive salinity due to the natural formation. In this study, the performance of the most widely used European diatom indices (IPS, IDG, IBD, EPI-D, TDI, and TI) was tested statistically by comparing them with the indicators of organic pollution (biological oxygen demand and ammonium-nitrogen), eutrophication (orthophosphate and nitrate-nitrogen) and salinization (electrical conductivity) in the Kizilirmak basin, Turkey. For this purpose, a total of 97 diatom samples from 33 rivers were collected seasonally in 2014 and 215 species were identified. Principal component analysis was performed to evaluate the "general degradation" in the basin, and linear regression was used to calculate the correlations with diatom indices. As a result, EPI-D, IPS, IBD, and TI were strongly correlated indices, respectively, while IDG and TDI had the lowest correlations with general degradation. Only the EPI-D index was significantly correlated with all environmental variables. Our results showed that the EPI-D index can be used for the ecological status assessment in terms of phytobenthos in the Kizilirmak basin in line with the Water Framework Directive.

Does occupational air pollution threaten the lung health of indoor workers more than those of bus drivers?: a cross-sectional study.

AIM: This study aimed to evaluate the lung health between professional bus drivers and white collar workers in metropolis municipality from Turkey. MATERIAL AND METHODS: Out of 126 bus drivers and 1100 office employees, data were analyzed from 243 indoor employees and 57 bus drivers. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, forced expiratory flow (FEF) 25-75% were measured, some data were collected with a questionnaire (work and environmental anamnesis, symptoms, smoking). RESULTS: The mean (±SD) values for FVC, FVC percent predicted value, FEV1, FEV1 percent predicted value, FEV1/FVC were 4.33 ± 0.99L, 96.5 ± 18.2%, 3.31 ± 0.87L, 84.5 ± 18.2%, 76.30 ± 9.23%, respectively. Sixty-six participants (22%) had FEV1/FVC proportions of less than 70%. After weighing for the propensity scores, there was a significant difference between bus drivers and indoor workers concerning FEV1/FVC grouping; while 65 (26.1%) indoor workers had FEV1/FVC proportions less than 70%, there were only two (3.9%) bus drivers (Chi-Square = 12.009, p = .001). The mean spirometry values were significantly different between the two groups in favor of the bus drivers (p < .05). Night cough was much more seen in the indoor workers (Chi-Square test = 9.019, p = .003). CONCLUSION: We conclude that there are no health risks associated with bus driving in a metropolitan city, concerning lung functions.

Limno-ecological assessment of Aras River surface waters in Turkey: application of diatom indices.

This study is the first attempt to evaluate the limno-ecological status of freshwater ecosystems in Aras River system (Turkey) using diatom metrics and multivariate analyses according to the European Union Water Framework Directive requirements. Samples were collected using the standard protocols from 17 sampling stations in August and October of 2014, and June of 2015. Deterioration of water quality in the Aras River catchment was remarked from the downstream of Karakoyunlu, Sarisu, and Bozkus creeks, which showed higher values of trophic index Turkey (TIT), trophic index (TI), and eutrophication and/or pollution index-diatom (EPI-D). These sites were also characterized by pollution tolerant taxa e.g., Cocconeis placentula, Gomphonema parvulum, Navicula cryptocephala, Navicula trivialis, and Tryblionella angustata. Sites S14-S17 had high ecological status according to TIT, supported by the score of EPI-D which indicated a good ecological condition for S14. The occurrence of pollution-sensitive species (e.g., Hannaea arcus, Cymbella affinis, Didymosphenia geminata, Meridion circulare, and Encyonema silesiacum) and the low nutrients like total phosphorus, orthophosphate and nitrate, conductivity, and BOD5 supported the high ecological status of S14-S17. The relationships between diatom assemblages and environmental variables were also illustrated by multivariate analyses. Spearman correlation analysis revealed that TIT had positive important correlations with total phosphorus (p < 0.01, r = 0.768). Trophic index and EPI-D had also significant correlations with environmental variables, but they had lower correlation coefficient than that of TIT. It seems that TIT could be a suitable diatom metric for assessing the ecological status of sampling stations in Aras River system and Mediterranean region. Our findings showed also that ecological statuses of surface waters should be evaluated due to the indices developed in their ecoregions.