Application Of Diatom Indices Research Articles

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.

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

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, tem-perature, 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, En-cyonema silesiacum, Navicula radiosa), indicated by multivariate analyses. The significant positive correlation of the TIT (P < 0.01, r = 0.789) with logPO4 indicated that TIT may be used as an appropriate diatom metric to assess the ecological status of surface waters in the Araban-Yavuzeli catchment.

Ecological status of Aquatic Ecosystems in the Gaziantep catchment (Turkey): application of diatom indices

Ecological status of Aquatic Ecosystems in the Gaziantep catchment (Turkey): application of diatom indices

Epiphytic diatoms as bioindicators of trophic status of Lake Modrac(Bosnia and Herzegovina)

Biodiversity of diatoms and applicability of diatom indices in biomonitoring based on littoral epiphytic samples of Lake Modrac were investigated. Diatoms were taken mostly from Phragmites australis stems in 2017, during which physical and chemical parameters of the water were measured. A total of 85 diatom taxa were identified. Gomphonema (13 spp.), Navicula (11 spp.), and Nitzschia (8 spp.) were the most abundant genera. Obtained values of trophic indices (TID, TvD, and TDIL) pointed to meso- to eutrophic status for most localities, while values of the IBD, EPI, ?D, and IPS indices indicated good ecological status, except for localities at the mouth of 2 main tributaries which had moderate or poor ecological status. Based on the hierarchical group average clustering and nonmetric multidimensional scaling, 4 groups were identified, mainly related to the sampling period, with higher spatial variation in species composition during summer. Since environmental legislation in Bosnia and Herzegovina still does not provide detailed instructions on using diatoms in biological assessment, results of this study can be useful for the development of biomonitoring tools for lakes in Bosnia and Herzegovina.

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, Sarısu, and Bozkuş 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.

Diatom diversity and ecological status of the Lasovacka and Lenovacka streams near Zajecar: Consideration of WFD implementation in Serbia

The development and improvement of the monitoring system of rivers according to the requirements of the Water Framework Directive (WFD) is essential for all European states because assigning a wrong ecological status class (misclassification) to a water body can have significant economic consequences. In order to point out some of the key issues of WFD implementation in Serbia, we conducted a one-year study of the composition and abundance of diatoms in the phytobenthos in two streams, the Lasovacka and Lenovacka, in eastern Serbia. The physicochemical quality elements were also used in the assessment of their ecological status. The diatom community exhibited a higher species richness in the Lasovacka (88 taxa) than in the Lenovacka stream (63 taxa). Such a detailed study enabled us to record some of the rare taxa, e.g. Caloneis budensis in the Lasovacka, which was the first finding of this species in Serbia. The Lasovacka and Lenovacka streams were downgraded to moderate and poor ecological status, respectively, because of the high nitrogen load. Since the monitoring results based on the diatom indices resulted in the assignment of two streams to a good ecological status, the possible reason for the mismatch between the biological and physicochemical quality elements could be due to the lack of analysis of benthic invertebrate fauna or the application of diatom indices that are insufficiently sensitive to the specific environmental pressure. The results of this study show that conducting a comprehensive ecological investigation of rivers within the framework of the WFD in Serbia is urgently needed.

Application of European biomonitoring techniques in China: Are they a useful tool?

This paper focuses on the application of various biomonitoring techniques in China. We report a study in the Pearl River Basin (Guangzhou) based on the application of diatom indices as well as a study on the waterways in Wuhan based on evaluation of toxicity (using phytotoxicity, Daphnia magna and Microtox™ tests) and the Extended Biotic Index (EBI). Regarding the diatom indices, acceptable results were obtained based on comparison of the chemical water quality level and the European and Japanese indices, despite a lack of taxonomic information. The toxicity tests applied to the Wuhan waterways (Yangtze and Han Rivers) produced interesting results and can be considered to represent a useful tool for water pollution control in this area. Application of the EBI in Wuhan produced results that were contradictory to the toxicological analyses, as there were no indications of toxicity, whereas EBI indicated poor water quality. It can be concluded that in principle, certain European biological indicators can be considered to represent feasible tools to be applied in China. However, further studies will have to be carried out to develop bioindices based on Chinese data sets. The use of bioindices based on macroinvertebrates is limited to less polluted and smaller rivers with a lithic river substratum, whereas diatom indices are also applicable under extreme conditions (e.g., under high pollution loads or in large river streams with sandy riverbed sediments through installing artificial substrates).

Ecology of the Szczecin Lagoon diatom flora with reference to the utility of diatom indices in assessing water quality

Abstract The study focuses on applying the diatom flora to evaluate environmental conditions of the Szczecin Lagoon. A total of 521 taxa (diatom species and varieties) of 74 genera were identified in the samples. Light microscope (LM) counts were processed with OM-NIDIA software to yield diatom indices. The diatom flora structure and relations between assemblages at individual sites were explored with multivariate analyses. Applicability of diatom indices in assessing the state of the Szczecin Lagoon was confirmed. The infer- ences produced by diatom indices were compared with those derivedfrom directly meas- uring physico-chemical water parameters and from using the diatom bioindicative charac-teristics. Diatom indices produced conclusions similar to those resulting from conventional application of diatom bioindicative potential. Both methods showed the Szczecin Lagoon to be eutrophic and moderately polluted. Key index words : Baltic Sea, bioindication, diatom indices, diatoms (Bacillariophyceae), Szczecin Lagoon Introduction Diatoms are commonly believed to be highly sensitive microorganisms, useful in environmental assessment. The presence or absence of certain taxa as well as their development allows to draw conclusions regarding the state of the water mi-lieu. The bioindicative potential of diatoms was explored in numerous studies in which salinity, eutrophication or saprobity was assessed (e.g. Geissler 1982, Geissler & Jahn 1984, Patrick 1984, Cox 1991, Fritz et al. 1991, Dixit et al. 1992, Round 1993, Hofmann 1994). A number of diatom-based environment assessment methods have been developed in recent decades. The methods involve matching certain diatom species of known indicative value to calculate the so-called diatom indices (Descy 1979, Lenoir & Coste 1996, SladeCek 1986, Prygiel et al. 1996, Dell'Uomo 1996, Kelly & Whitton 1995, Watan- abe 1986, Coste & Ayphassorho 1991). As the benthic diatom-based indices are now a major tool in riverine water quality assessment, it

The use of diatom assemblages as ecological indicators in highly stratified estuaries and evaluation of existing diatom indices

Diatom indices are used to evaluate the ecological status of rivers but they have been rarely applied in estuaries. This study aimed to identify the diatom species indicating the main environmental gradients and pressures in a highly stratified estuary; and to evaluate the applicability of existing freshwater diatom indices. Marine influence due to salt-wedge intrusion and sea water mixing appeared as the main factor affecting diatom community. Three diatom assemblages were identified: indicators of riverine conditions (without marine influence), indicators of estuarine conditions (heterogeneous conditions with higher conductivities due to marine influence) and those specifically indicating well-established salt-wedge situations. Nowadays, the main human pressure affecting diatom community in the Ebro Estuary is the hydrological alteration resulting from flow regulation and abstraction. Several limitations were encountered in the application of diatom indices (e.g. inverse response with nutrients; ecologically important species not considered). Therefore, their use in estuaries should be done cautiously.

Application of diatom indices in the evaluation of the water quality in Estonian streams

Application of diatom indices in the evaluation of the water quality in Estonian streams

Application of Diatom Indices in a Planted Ditch Constructed for Tertiary Sewage Treatment in Schwaan, Germany

Application of Diatom Indices in a Planted Ditch Constructed for Tertiary Sewage Treatment in Schwaan, Germany

Application of Diatom Indices in a Planted Ditch Constructed for Tertiary Sewage Treatment in Schwaan, Germany

The present study quantified the decrease of organic and trophic pollution in a constructed wetland used for tertiary sewage treatment. Different diatom indices [the saprobic zoning system of LANGE-BERTALOT (1978, 1979), the saprobic index (SI) of ROTT et al. (1997), as well as the trophic indices of SCHIEFELE and KOHMANN (1993); KELLY and WHITTON (1995) and ROTT et al. (1999)] were tested for their effectiveness in detecting changes in water quality of highly organic and trophic waters. The saprobic zoning system detected nearly the same pollution levels as the chemical data, but the measured saprobic characteristics (e.g. TOC: Total Organic Carbon) did not correspond to significant changes in the diatom assemblages. The data suggested that the results of the saprobic zoning system were influenced by differences in nitrate concentrations. The trophic diatom indices correlated relatively well with the inorganic compound chemical data.