No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Responses of Epilithic Diatom Communities to Environmental Gradients in Some Finnish Rivers
Abstract
Responses of the epilithic diatom communities to environmental gradients were analysed at 135 river stations in Finland. In addition, the biological quality of the water was evaluated using diatoms in five rivers having different types of human pressures. According to CCA, conductivity, total P, pH and humus content had the most significant effect on the diatom community structure. The ratio of the constrained axis (λ1) and first unconstrained axis (λ2) was highest for conductivity (1.21), total P (0.83) and pH (0.67). Physical factors had somewhat weaker effects. Five different diatom community types were separated in chemically different rivers using ordination. The effects of purified sewage on diatom-inferred water quality estimates were strongest in late summer. The effects of cattle-farming and cultivation were difficult to separate.
... It has been noted that the genus Nitzschia is the most commonly observed genus in waters with a rich concentration of nutrients, poor in dissolved oxygen, and under the influence of organic pollution (Palmer, 1969;Van Dam et al., 1994). Nitzschia palea has been recorded as the most tolerant species to organic pollution worldwide (Gómez, 1998;Gómez and Licursi, 2001;Soininen, 2002;Dere et al., 2006;Szczepocka and Szulc, 2009). This species can be found even in eutrophic and heavily polluted waters. ...
... This species can be found even in eutrophic and heavily polluted waters. Again, several researchers have stated that this species is an indicator of organic pollution in rivers (Khan, 1990;Kelly, 1998;Soininen, 2002). In the present study, Nitzschia palea was found with low relative density and rarely at the station 3. It has been indicated that Nitzschia amphibia Grunow is tolerant to organic pollution (Van Dam et al., 1994). ...
The epilithic diatoms of Munzur Stream, together with the chemistry and physical variables of the water, were examined in the samples taken annually from 3 stations on the creek between October 2016 and September 2017. A total of 69 diatom taxa were identified benthic habitat. Cocconeis placentula, Cymbella affinis, Cymbella excisiformis , Didymosphenia geminata, Gomphonema olivaceum, and Hannaea arcus became diatoms at all that reached significant relative abundance. Shannon-diversity (H’), species evenness (J’), species richness (S) in each station varied between stations and months. Regarding diversity (H), values ranged from 1.54 (in December, at S3) to 2.99 (in October, at S3). Evenness ranged from 0.09 to 0.22 at station S3 in September (at S1, in September). Evenness ranged from 0.09 at site S3 in September, to 0.22 at S1, in September. All stations and species were close to 1 value. Canonical correspondence analysis indicated that three environmental variables (TN,TP, PO4-3) significantly affected the distribution of epilithic diatom. The studied part of stream was characterized by the species susceptible to nutrients such as Didymosphenia geminata, Cymbella excisiformis and Hannaea arcus which are found in the regions located in high lands having advanced ecological status. The results of the present study highlighted the importance of diatoms as a bio-indicator for health condition of a stream.
... N. acicularis, (Kützing) W.Smith 1853, and F. crotonensis were negatively affected between 1100 and 1500 μS cm −1 , consistent with their affinity for conductivities below 1500 μS cm −1 (van Dam et al., 1994). N. palea, N. paleacea, and Navicula veneta were positive responders to salinity and are known tolerant species above 1600 μS cm −1 (van Dam et al., 1994;Soininen, 2002;Karacaoğlu & Dalkıran 2017). ...
... These treatments had notable relative abundances of Navicula veneta and E. minima, which are known indicators of nutrient enrichment (Cochero et al., 2015;Delgado & Pardo, 2015;Nunes et al., 2019). Moreover, Nitzschia palea is widely known as a tolerant species to conductivity and nutrients (Soininen, 2002;Karacaoğlu & Dalkıran, 2017;Pajunen et al., 2017;Nunes et al., 2019) and was abundant in treatment 6 assemblages. Hence, it is difficult to determine whether the elevated relative abundances of these species are related to salinity alone. ...
Water quality guidelines are an important tool for managing environmental pressures on freshwater streams, but guidelines are frequently set using conditions from reference sites that are assumed to be unimpacted. Using biological thresholds potentially provides a better foundation for guidelines. However, guidelines based on field observations alone may be compromised by confounding influences. This study used an outdoor stream mesocosm, an artificial substrate (rope), and six salinity concentrations to assess the veracity of a diatom–salinity threshold determined previously in natural temperate South Australian streams. In addition, shaded treatments assessed the synergistic influences of salinity and reduced sunlight. Salinity had the strongest effect on diatoms, influencing both species and functional compositions. Species diversity and richness, and functional diversity had negative correlations with salinity. Shade strongly reduced diatom concentrations and altered species composition, with no observed interaction between salinity and light. Threshold Indicator Taxa ANalysis indicated a salinity threshold of 1610 μS cm⁻¹ for both shade treatments, lower than the upper limit of the range used in current freshwater guidelines. This study recommends a new candidate guideline of 1600 μS cm⁻¹ for regional freshwater streams and suggests that contemporary methods for deriving water quality guidelines may not adequately protect aquatic health.
... sınıf su kalitesinin indikatör organizmaları arasında yer almaktadır. C. placentula'nın ileri derecede ötrofik sularda da iyi geliştiği belirlenmiştir (Kelly ve Whitton, 1995;Kwandras ve ark., 1998;Soininen, 2002). Bununla beraber, Lange-Bertalot (1979) ve Szczepocka ve Szulc (2009) C. placentula'yı organik kirliliğe hassas olarak sınıflandırmıştır. ...
... N. palea'nın araştırma alanında her zaman hafif kirliliğin olduğu 3. ve 4. istasyonlarda baskın olduğu görülmüştür. N. palea'nın organik kirliliğe en toleranslı tür olarak rapor edildiği çok sayıda çalışma vardır (Gómez ve Licursi, 2001;Soininen, 2002;Gürbüz ve Kıvrak, 2002;Soylu ve Gönülol, 2005;Dere ve ark., 2006;Kalyoncu ve ark., 2009;Szczepocka ve Szulc, 2009). Yayılımcı bir diyatome türü olan Didymosphenia geminata, genellikle yüksek arazilerde ve kuzey bölgelerde bulunur. ...
The Ikizdere Valley is one of priority ecologic region within 200 areas where is under protection in the world. It is natural conservation area. In this study, epilithic algal diversity of Cimil Stream in the Cimil (Tiron) Valley where is one of the most important protection areas were investigated. The ecological structure of the stream is to determine by using indicator algae. According to sampling results obtained from four different stations after rainy and dry seasons (November 2010 and August 2011), total 113 taxa belongs to five different division were identified. Diatoms have the most species diversity in terms of other groups (74, 65%). This was followed by Cyanophyta (28, 25%), Charophyta (6, 5%), Chlorophyta (4, 4%) and Euglenophyta (1, 1%). Achnanthidium minutissimum, Cocconeis pediculus, C. placentula, Cymbella affinis, Gomphonema parvulum, G. truncatum, Encyonema minutum, Hannaea arcus, Navicula menisculus, N. salinarum ve Nitzschia palea are common and dominant diatom species in the Cimil Stream. Indicator species showed that the ecological situation of the Cimil Stream is not yet under intense pressure pollution. However, it is seen that the stream showed a change towards β-α-mesosaprobic conditions from oligosaprobic top to bottom. For the area's tourism potential is very high, it is recommended that the necessary measures take as to maintaining ecological structure in future.
... Such liquid wastes as explained above discharged into the river cause notable algae growth which in turn leads to eutrofication (Haslam, 1995). In parallel, many researchers have reported that Nitzschia palea is an organic pollution indicator in waters which are rich in domestic and organic waters (Khan, 1990, Kelly, 1998, Soininen, 2002. That species are in high ratio may denote that river is contaminated with to freshwater. ...
... All these contaminants may concentrate on the river bed sediments during dry seasons. These immense factors have an effect on the aquatic living resources, such as African catfish, in the Asi basin during dry season (Yalçın et al. 2001;2002). This is usually associated slowing down effect of the antibiotic so called Pandorinin which is secreted by Pandorine on the development of the Scenedesmus and Cosmarium. ...
A total of 137 specimens of Capoeta barroisi (Heckel 1843) were caught from the Asi River between February 2002 and January 2003. It was noticed that 92.7% of the guts were full. C. barroisi mainly feeds on Chrysophyta, Cyanophyta and Chlorophyta saving a few Ciliata and Protozoa. Common food groups for this fish species were found to be Chrysophyta 30.15% though Dactylococcopsis sp. 17.62%, which are members of Cyanophyta were dominant species. It was also noted that there were remarkable alterations in food composition depending on the four season. Especially, during the spring, Chrysophyta reproduce under suitable environmental conditions and IRI GII indicies appeared to be important.
... sınıf su kalitesinin indikatör organizmaları arasında yer almaktadır. C. placentula'nın ileri derecede ötrofik sularda da iyi geliştiği belirlenmiştir (Kelly ve Whitton, 1995;Kwandras ve ark., 1998;Soininen, 2002). Bununla beraber, Lange-Bertalot (1979) ve Szczepocka ve Szulc (2009) C. placentula'yı organik kirliliğe hassas olarak sınıflandırmıştır. ...
... N. palea'nın araştırma alanında her zaman hafif kirliliğin olduğu 3. ve 4. istasyonlarda baskın olduğu görülmüştür. N. palea'nın organik kirliliğe en toleranslı tür olarak rapor edildiği çok sayıda çalışma vardır (Gómez ve Licursi, 2001;Soininen, 2002;Gürbüz ve Kıvrak, 2002;Soylu ve Gönülol, 2005;Dere ve ark., 2006;Kalyoncu ve ark., 2009;Szczepocka ve Szulc, 2009). Yayılımcı bir diyatome türü olan Didymosphenia geminata, genellikle yüksek arazilerde ve kuzey bölgelerde bulunur. ...
The Ikizdere Valley is one of priority ecologic region within 200 areas where is under protection in the world. It is natural conservation area. In this study, epilithic algal diversity of Cimil Stream in the Cimil (Tiron) Valley where is one of the most important protection areas were investigated.
... Although Achnanthes minutissima and Navicula minima occurred widely across the entire land use intensity gradient, they represented notably high relative abundances at many urban sites. N. minima is considered to be a pollution-tolerant species (Van Dam et al., 1994), often occurring in polluted waters (Soininen, 2002;Duong et al., 2006;Walsh and Wepener, 2009). A. minutissima is regarded as one of the most widely distributed diatom species. ...
... For example, Achnanthes minutissima var. saprophila typically occurs in polluted waters (Soininen, 2002;Ndiritu et al., 2006). We were, however, unable to separate the different varieties consistently in a light microscope and they were thus grouped together. ...
... Lavoie et al. (2008) considered that relative abundance reflects the community structure and stated that the complexity of the community influences the time needed for restructuring the taxa. Ecological studies performed exclusively with diatoms use permanent slides, counting oxidized valves, and the results are expressed as relative abundance (Keithan et al., 1988;Yang et al., 1996;Kelly & Whitton, 1998;Soininen, 2002;Mercado, 2003;Gevrey et al., 2004;Rey et al., 2004Rey et al., , 2008Harding et al., 2005;Tison et al., 2005;Leira & Sabater, 2005;Frankovich et al., 2006;Passy, 2006;Salomoni et al., 2006;Walker & Pan, 2006;García-Rodríguez et al., 2007;Potapova & Charles, 2007;Kelly et al., 2008;Lavoie et al., 2008;Leira et al., 2009;Bere & Tundisi, 2011). To derive the indicator species, Kelly et al. (2008) calculated the maximum relative abundance, for each diatom taxon, to identify taxa that could be used as indicators for a particular environmental status. ...
... However, the sample units along the year and specific differences in biovolume among the taxa drove the ordination analysis, highlighting the most impacted rivers, as well as relative abundance, but with low statistic robustness. Applying diatom relative abundance in ecological studies, there are clear relationship between community distribution and physical and chemical factors both in lakes (Gottschalk & Kahlert, 2012;Kovács et al., 2006), in rivers (Soininen, 2002;Kireta et al., 2012;B-Béres et al., 2014) or in streams (Hering et al., 2006;Stenger-Kovács et al., 2013). Leira & Sabater (2005) showed that conductivity and BOD influence composition variation and also found that Cyclotella, Navicula, and Nitzschia abundances increase with conductivity and BOD. ...
We present the result of the diatoms study at the mouths of the Sinos, Gravataí, Caí and Jacuí rivers, with emphasis on the form of the plastids and their arrangement within the cell from the Jacuí Delta. Although this character has been neglected in recent decades, it is currently recognized by its ecological importance. We analyzed monthly samples, collected at the deep of 20 cm in the pelagic zone from September 2009 to August 2010. 64 taxa, distributed in three classes, 11 orders, 18 families and 23 genera were identifi ed. The most representative families wereBacillariaceae (16 taxa),Naviculaceae(8),Aulacoseiraceae (7),Eunotiaceae (5) andPinnulariaceae (5). The genusNitzschia was the richest, with 15 species. The highest richness was observed in the Rio dos Sinos (52 taxa) and the lowest in Jacuí River (38 taxa). Only 24 taxa were present in the four rivers and six taxa were exclusive from one river. Considering the previous knowledge of the diatoms occurring in the rivers mouths of the Delta Jacuí, 43 species are mentioned for thefi rst time, which demonstrates the contribution of this study.
... Lavoie et al. (2008) considered that relative abundance reflects the community structure and stated that the complexity of the community influences the time needed for restructuring the taxa. Ecological studies performed exclusively with diatoms use permanent slides, counting oxidized valves, and the results are expressed as relative abundance (Keithan et al., 1988;Yang et al., 1996;Kelly & Whitton, 1998;Soininen, 2002;Mercado, 2003;Gevrey et al., 2004;Rey et al., 2004Rey et al., , 2008Harding et al., 2005;Tison et al., 2005;Leira & Sabater, 2005;Frankovich et al., 2006;Passy, 2006;Salomoni et al., 2006;Walker & Pan, 2006;García-Rodríguez et al., 2007;Potapova & Charles, 2007;Kelly et al., 2008;Lavoie et al., 2008;Leira et al., 2009;Bere & Tundisi, 2011). To derive the indicator species, Kelly et al. (2008) calculated the maximum relative abundance, for each diatom taxon, to identify taxa that could be used as indicators for a particular environmental status. ...
... However, the sample units along the year and specific differences in biovolume among the taxa drove the ordination analysis, highlighting the most impacted rivers, as well as relative abundance, but with low statistic robustness. Applying diatom relative abundance in ecological studies, there are clear relationship between community distribution and physical and chemical factors both in lakes (Gottschalk & Kahlert, 2012;Kovács et al., 2006), in rivers (Soininen, 2002;Kireta et al., 2012;B-Béres et al., 2014) or in streams (Hering et al., 2006;Stenger-Kovács et al., 2013). Leira & Sabater (2005) showed that conductivity and BOD influence composition variation and also found that Cyclotella, Navicula, and Nitzschia abundances increase with conductivity and BOD. ...
Abundance and biomass estimates are metrics usually taken for phytoplankton assays. Biomass is a proxy measure today in phytoplankton assays, while relative abundance is broadly used in diatoms investigations and application of ecological indexes. The question is how the two metrics respond to environmental conditions, based on diatoms species composition, in the plankton of lotic system, using the same statistical approach. The investigation was carried out based on monthly plankton sampling in four rivers during an annual cycle in southern Brazil. Relative abundance and relative biomass of diatoms showed distinct responses for each river, and the dominant species according to each metric were different. Relative abundance significantly correlated with seven of the eight physical and chemical variables, while relative biomass did not. Both metrics were appointed to the major diatom species of each river, but biomass showed low statistic robustness. The analysis with higher taxonomic rank (families) yielded more coherent outcomes between the metrics. The results showed that diatom relative abundance is effective to relate the composition to environmental conditions; therefore, the abundance should not be neglected in studies of phytoplankton structure and dynamics, mainly when the diatoms are dominant in the community, and the low taxonomic rank ecological indication is regarded.
... In this study, species composition reflected well the nutrient status of the streams. In Vantaanjoki, the most common diatoms, such as Cyclotella atomus, Cocconeis placentula and Gomphonema parvulum, are all typical species for mesotrophic and eutrophic streams and streams affected by organic loading (Soininen, 2002). In Luutajoki and Evojoki, the species present were mainly typical oligotrophic species, such as Achnanthes linearis, Eunotia ssp. ...
... In Luutajoki and Evojoki, the species present were mainly typical oligotrophic species, such as Achnanthes linearis, Eunotia ssp. and Gomphonema angustatum (Soininen, 2002;. In Luutajoki and Evojoki, only one or few species dominated, whereas in Vantaanjoki several species were co-dominant. ...
Diatoms are used as indicators of water quality as they respond predictably to many water chemistry variables and their ecology is relatively well known. However, temporal variation in diatom assemblages remains poorly resolved and studies covering large temporal and spatial scales are urgently needed. Here, we studied how diatom assemblages vary within and between three years at eight boreal stream sites located in Finland using Mantel tests and ordination analyses. Our study streams differed greatly in their trophic level and size: Vantaanjoki is mesotrophic to eutrophic and large, whereas Luutajoki and Evojoki are oligotrophic and smaller. We found that species composition reflected well the status of the sampled streams. In Vantaanjoki, the most common diatoms were all typical species for mesotrophic to eutrophic streams, whereas oligotrophic streams were characterized by species with narrow ecological niches confined to nutrient-poor water. According to Non-metric Multidimensional Scaling (NMDS), the between-year variation was nearly comparable at all sites, eutrophic sites generally showing slightly higher between-year variation. The reasons for large between-year differences in assemblages were probably related to different weather conditions between the years. The Mantel tests also showed a notable degree of within-year variation in all assemblages. Therefore, we suggest that ecosystem size and productivity act in different directions in the data, resulting in no major differences in the turnover rates at sampled sites. However, NMDS analyses conducted simultaneously for the whole diatom data showed that temporal variation does not confound the large differences in assemblages between eutrophic and oligotrophic streams and that temporal variation may add slightly less noise in spatial assemblage variation in oligotrophic streams. This suggests that site classifications based on diatoms may be overall slightly more robust in oligotrophic waters, whereas in mesotrophic to eutrophic waters, misclassifications may be more likely due to large temporal variation in assemblages.
... Les analyses physico-chimiques des eaux permettent de connaître la nature et la concentration des contaminants présents dans l'eau au moment où les prélèvements ont été effectués. Par l'étude des organismes aquatiques, on procède à une meilleure évaluation de l'intégrité des écosystèmes car leur présence ou leur abondance reflète les conditions du milieu qui se sont succédées durant leur développement (BEYENE et al., 2009;JÜTTNER et al., 1996;SOININEN, 2002). Parmi les organismes utilisés comme « bioindicateurs » de la qualité des eaux, les algues, particulièrement les diatomées, occupent une place de choix pour diagnostiquer l'état de santé des rivières, car elles répondent de manière rapide à l'eutrophisation des eaux ainsi qu'aux diverses pollutions (MORIN, 2006;ROTT et al., 1998;ROUND, 1991). ...
... Ces auteurs ont noté un développement important des espèces polluo-résistantes dans les sites localisés en aval des stations d'épuration des égouts et dans les tronçons des cours d'eau urbains très polluées par les rejets domestiques et industriels. L'abondance de D. contenta et de N. cryptocephala, espèces couramment rencontrées dans les sections oligotrophes à eutrophes de divers hydrosystèmes (SOININEN, 2002;VAN DAM et al., 1994), est en faveur de l'amélioration de la qualité de l'eau de la station Mf7 déjà soulignée par les descripteurs physico-chimiques. ...
Sont considérés dans cette étude, l’impact des rejets polluants d’origines urbaine et industrielle sur la qualité des eaux du Mfoundi, l’abondance, la richesse spécifique et la structure des communautés diatomiques qui peuplent ce cours d’eau. Le calcul du pourcentage de taxons tolérants à la pollution organique a permis d’évaluer la réponse de ces algues à l’enrichissement du milieu en matières organiques. Les analyses physico-chimiques des eaux mettent en évidence l’existence d’un gradient de pollution croissant de l’amont à l’aval de la rivière. Le cours supérieur présente des eaux turbides avec des teneurs élevées de matières en suspension. Les cours moyen et inférieur sont fortement contaminés par les matières organiques qu’apportent les eaux usées domestiques et les effluents industriels qu’ils reçoivent. Au total, 237 taxons de diatomées épilithiques, majoritairement cosmopolites, appartenant à 39 genres répartis dans 25 familles, ont été inventoriés. Le développement dans le cours supérieur du Mfoundi de taxons tels que Gomphonema parvulum (Kützing) Kützing et variétés, Gomphonema gracile Ehrenberg et Navicula radiosa Kützing, est associé essentiellement à la turbidité des eaux de ce tronçon. La distribution de Nitzschia palea (Kützing) W. Smith, Navicula geoppertiana (Bleisch) Grunow, Navicula mutica Kützing et Pinnularia subcapitata Gregory dans les cours moyen et inférieur est étroitement liée à la charge organique et la forte minéralisation des eaux. N. palea est l’espèce la plus abondante dans les stations Mf5 (66 %) et Mf6 (53 %), indiquant une importante pollution organique de ces sites sous l’effet des rejets des industries brassicoles et vinicoles opérant dans leur voisinage. La variation spatiale de la diversité spécifique n’a pas souligné toute l’ampleur de l’altération de la qualité des eaux; toutefois, l’analyse du pourcentage de taxons polluo-tolérants révèle que les apports graduels en nutriments et en matières organiques dans les cours moyen et inférieur contribuent à l’eutrophisation progressive de ces secteurs. Il est montré que les diatomées épilithiques sont sensibles à la variation de la qualité de l’eau du Mfoundi, et peuvent être utilisées comme bioindicateurs de l’état de santé des cours d’eau urbains du Cameroun.
... Palmer (1969) reported that N. palea was the diatom species most tolerant of organic pollution. 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. ...
... The abovementioned species are also established as indicator species of generally β-mesosaprobous or eutraphentic 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). ...
The Akarçay is the most important stream in the Afyonkarahisar region in central Turkey. In this study, the relationships between epipelic diatoms, macrophytes, and the water quality of Akarçay Stream are presented. According to Canonical Correspondence Analysis (CCA), BOD5, COD, TDS, NH4-N, NO2-N, and PO4-P had the most significant effects on the diatom and macrophyte community structures of the stream. According to CCA and Correspondence Analysis (CA), dominant diatom species and macrophytes constituted two groups, eutrophic and polluted. While eutraphentic taxa were abundant among upstream diatoms, hypereutraphentic taxa were found downstream in the Akarçay. The diatom assemblages in the sites upstream were generally characterized by an abundance of β-mesosaprobous and α-mesosaprobous species, while the diatom assemblages downstream had a very high abundance of polisaprobous species. Eutrophic and hypertrophic macrophyte taxa (such as Lemna trisulca, Potamogeton nodosus, and Ranunculus sp.) covered a high percentage of the stream bottom. Both diatom indices and macrophyte indices with the exception of the Biological Macrophyte Index of Rivers (IBMR) were correlated with BOD5, COD, TDS, NH4-N, NO2-N, PO4-P, and EC. Physicochemical variables, diatom and macrophyte taxa and the results of diatom and macrophyte indices indicated that the Akarçay stream basin is eutrophic and organically polluted.
... Conductivity and ion composition as the most important variables shaping diatom communities was highlighted quite early (Cholnoky, 1968), and then have been repeatedly shown in several studies (Pan et al., 1996;Carpenter & Waite, 2000;Winter & Duthie, 2000;Almeida, 2001;Trobajo, 2004;Soininen, 2007;Soininen & Weckström, 2009;Bere & Tundisi, 2011b;Potapova, 2011;Virtanen & Soininen, 2012, Srivastava et al., 2017, Ali et al., 2018). Even at low salinity level, the effect of salinity on diatom communities is well documented (Soininen, 2002;Virtanen & Soininen, 2012;Heikkinen et al., 2022) and already a 0.5 mg l −1 additional salt content can change the community structure of diatoms (Dixit et al., 1999). However, understanding the exact effect of salinity on species composition and ecosystem functioning tillo et al., 2018) including the need (i) to separate the effects of the different components of salinity and thus, (i-a) to distinguish the natural components from anthropogenic ones and (i-b) to separate the effects of salinity related pollution from, e.g., eutrophication or organic pollution. ...
Both natural and anthropogenic processes can lead to the increasing salinity of surface waters. The knowledge about the ecological consequences of salinization on the biota is limited especially in case of microbiota, like diatoms. We collected the existing knowledge about the relationship between salinity and diatoms in fresh and saline waters. Based on the available papers, conductivity and ion composition are the most important variables shaping diatom communities. Secondary salinization can mask regional differences in diatom assemblages. Trait-based analyses highlight the competitive advantages of motile guild and the extreme trait categories in these environments. The increasing conductivity along a wide conductivity scale decreases the alpha-diversity. Salinization induces the spread and invasion of marine and brackish species into inland freshwaters as well as that of freshwater species tolerating elevated conductivity and/or need specific ions. Concerning food webs, salinity can directly change diatom communities and the subsequent upper trophic levels but most likely this effect manifests as a top-down regulation. Applicable diatom indices are available to assess the level of salinization. Furthermore, diatom-inferred salinity reconstructions are widely applied to assess the past changes of salinity. However, future models predicting ecological consequences of salinization are scarce and sometimes contradictory.
... The community of periphytic algae has a wide range of adherence to substrates, with loosely attached species capable of exhibiting a wide range of dispersal capacities (Algarte et al., 2014;, linked to mass effect processes (Kristiansen, 1996;Soininen, 2002;Franceschini et al., 2009;Heino, 2010;Dong et al., 2016;Soininen et al., 2016;Jamoneau et al., 2017). On the other hand, species tightly attached to the substrate have a lower dispersal capacity and may be associated with "limited dispersal" processes (Algarte et al., 2014(Algarte et al., , 2017. ...
Environmental and dispersal drivers are determinants of periphyton metacommunities. However, the effects of these predictors can vary according to the facet of biodiversity assessed. In this study, we assessed the relative importance of local environment (i.e., limnological variables), regional landscape (i.e., land use), and spatial distance (i.e., overland and watercourse dispersal routes) components for the periphytic community in 30 Cerrado stream sites. For this, we estimated different metrics, such as the total density, beta diversity, local contribution to beta diversity (LCBD), species richness, and composition. This last metric was obtained considering the complete and deconstructed communities according to the type of adhesion to the substrate. We found 128 species with a predominance of the Bacillariophyceae, of which most have loosely adherence to the substrate. The algae community showed a high turnover of species along the hydrographic drainage. Besides, spatial distances were signifcant for species richness, total density, and species composition metrics using overland or watercourse distances. The spatial distance was also crucial for species composition tightly adhered to the substrate. Nevertheless, any community metric had no local environment and regional landscape effects. Therefore, on a large spatial scale, the effect of the spatial component can be attributed to species dispersion limitation, whereas on a finer spatial scale, mass effect was the primary process driving the variation among communities. In this sense, while for some species dispersal is limited by higher distances, for others dispersing to streams with suboptimal conditions can be associated with physiological aptitudes and high reproductive rates, which
allow for the maintenance of species in the studied stream sites.
... Benthic diatoms function as an important component of sustaining aquatic ecosystems health. Many studies have reported that the composition and structure of benthic diatom are affected by various chemical and physical environmental variables (Carpenter and Waite, 2000;Soininen, 2002;Leira and Sabater, 2005;Ndiritu et al., 2006;Urrea and Sabater, 2009). ...
Benthic diatom assemblages on the natural substrata at Balikhli River (northwest Iran) were investigated monthly. A total of 96 samples were collected from epilithic and epipelic substrata. A total of 110 taxa from 49 genera were identified. The most abundant diatom species were Cyclotella meneghiniana, Diatoma moniliformis, Nitzschia inconspicua, Planothidium lanceolatum and Gomphonema olivaceum. Non-metric multidimensional scaling (nMDS) analyses revealed explicit differences between diatom communities of stony and sediment substrates. Although common diatom taxa were not restricted to single substrates, some taxa had higher tendencies to every substrate. The nMDS analysis also showed differences between summer and autumn samples. Canonical correspondence analysis (CCA) of groups resulted from cluster analysis, showed that the nutrient concentration gradient, pH were the most important factors affecting the composition of diatom assemblages and species distribution. In our study orthophosphates had greater effect than nitrates, and Gomphonem parvulum and Navicula recenswere found in phosphate rich samples. Anthropogenic input including agricultural and domestic wastes may be responsible for high levels of these parameters. Alkali volcanic rocks and limestone sediments underlying the watershed could explain the high pH in the Balikhli River. In total
67.5% of the identified species in the river are considered as alkaliphilous. The findings of this study denote that the main determinants of variation in benthic diatom communities of Balikhli River result from a combination of land use patterns caused by human activities, river hydrology and natural phenomena including geology.
... Watershed urbanization causes the shift of diatom species from the sensitive to the tolerant (Nedeau et al., 2003). For instance, the loss of sensitive species (e.g., Eunotia spp.) was observed in a boreal, urbanized region in southern Finland (Teittinen et al., 2015) and in epilithic diatom communities in some Finnish rivers (Soininen, 2015), whereas tolerant species (e.g., Navicula gregaria, Gormphonema parvulum and Surirella brebissonii) were more common in polluted and eutrophic urban streams (Lange-Bertalot, 1993;Van Dam et al., 1994), which in turn changed the diatom community features represented as diatom metrics. Recently, the response in diatom metrics has been successfully used as potential indicators of local environmental variables (Newall and Walsh, 2005). ...
... Pollution had a negative impact on diversity of diatoms and led to increase of dominant taxa but decrease of diversity. Several researchers reported that this species was an important indicator for organic pollutions in streams [15,16,17]. Nitzschia palea is also described to tolerate heavy metals and to be the characteristic species of streams and lakes with heavy metal contamination [13]. ...
ABSTRACT
Epilithic diatom community of Tohma Stream,
as well as physicochemical properties of the stream
were studied through samples collected from the
specified 4 stations in monthly periods for one year.
70 species from 21 genera were identified in the
study. In epilithon in the stations, Navicula spp. (16
taxa) was the most remarkable genus in terms of
both number of species and the number of individuals from species and this was followed by Cymbella
(13 taxa) and Nitzschia (9 taxa). The water quality
in the Tohma stream varied at different stations
based on levels of pollution. The epilithic diatom
communities responded to changes in the aquatic
environment. Dominant species had variation
among the stations. Dominant species of the station
1 were Cocconeis placentula, Diatoma vulgaris,
Cymbella affinis and Gomphonema olivaceum.
Navicula cryptocephala, C. minuta, Ulnaria ulna,
Nitzschia amphibia, and N. thermalis were dominant diatoms of the stations 2 and 3. Dominant
diatoms of the station 4 were Achnanthidium
minutissimum, N. palea, Gomphonema parvulum,
and Surirella angustata, diversity of diatoms also
varied in all stations in parallel to water quality.
Also, station 4 in Beyler Brook in which wastes of
1st and 2nd Organized industry zones are discharged
joins to Tohma stream.
We concluded that Tohma stream has a water
quality gradient and this led to apparent variances
in species composition of diatom across the stream.
The results have confirmed that epilithic diatoms
are crucial biological indicators to evaluate ecological quality of Tohma stream.
KEYWORDS:
Tohma Stream, Epilithic diatoms, Water quality, Pollution
... Other colored symbols represent sites and sampling months [station 1, circle; station 2, up-triangle; station 3, diamond; station 4, star; station 5, down-triangle; station 6, square; red, summer (June, July, August); yellow, autumn (September, October, November); gray, winter (December, January, February); blue, spring (March, April, May)] (Afor, Asterionella formosa; Agra, Aulacoseira granulata; Plan, Planothidium lanceolatum; Alyb, Amphora libyca; Asta, Astasia sp.; Ccyc, Cyclotella cretica var. also known to be dominant in urban-polluted rivers and to be highly pollution-tolerant (Soininen 2002;Ács et al. 2004;Bere and Tundisi 2011). Schizothrix species are considered to be characteristic species of stream assemblages (Radloff et al. 2010). ...
Phytoplankton and epipelon assemblages form the main constituents, and they are producers in aquatic ecosystems, such as streams and rivers. This study was carried out between May 2008 and April 2009 to determine the impacts of polluted water on species variations, compositions, and community metrics in phytoplankton and epipelon at six stations on Ankara Stream. A total of 231 taxa were recorded during the study period, with 131 Bacillariophyta, 3 Charophyta, 41 Chlorophyta, 30 Cyanobacteria, 25 Euglenophyta, and 1 Ochrophyta. Heterogeneity of the stream stations was determined by the use of hierarchical cluster analysis (HCA). Community metrics were compared by using non-parametric tests, while canonical correspondence analysis (CCA) was used for the relationships between environmental variables and species. Variations in water quality and species composition along the stream flow revealed a significant spatial heterogeneity (p < 0.05). However, the upper stations of the stream were represented by unpolluted water quality with low nutrients and conductivity, and the mid- and downstream stations were characterized by high concentrations of ammonia (up to 60 mg L⁻¹) and o-phosphate (up to 25 mg/L), with low concentrations of dissolved oxygen (< 1 mg L⁻¹). The results, clearly supported by indicator taxa, showed that various domestic and industrial discharges affected the increase in pollution and the spatial heterogeneity. The findings obtained in this study will contribute to future improvements in Ankara Stream watershed studies.
... Benthic diatoms function as an important component of sustaining aquatic ecosystems health. Many studies have reported that the composition and structure of benthic diatom are affected by various chemical and physical environmental variables (Carpenter and Waite, 2000;Soininen, 2002;Leira and Sabater, 2005;Ndiritu et al., 2006;Urrea and Sabater, 2009). ...
Benthic diatom assemblages on the natural substrata at Balikhli River (northwest Iran) were investigated monthly. A total of 96 samples were collected from epilithic and epipelic substrata. A total of 110 taxa from 49 genera were identified. The most abundant diatom species were Cyclotella meneghiniana, Diatoma moniliformis, Nitzschia inconspicua, Planothidium lanceolatum and Gomphonema olivaceum. Non-metric multidimensional scaling (NMDS) analyses were performed to visualize relationships between diatom communities from different samples, substrates, seasons and sites. Although n-MDS analysis revealed explicit differences between diatom communities of two substrate but common diatom taxa were not restricted to single substrates. The nMDS analysis showed differences between summer and autumn samples. Diatom composition was diverse at every investigated site. SIMPER analysis determined the most representative taxa of the statistically different groups of seasons, stations and substrates. Cluster analysis of samples identified three major groups based on diatom assemblages. Canonical correspondence analysis (CCA) of groups resulted from cluster analysis, showed that the nutrient concentration gradient, pH were the most important factors affecting the composition of diatom assemblages and species distribution. The findings of this study denote that the main determinants of variation in benthic diatom communities of Balikhli River result from a combination of land use patterns caused by human activities, river hydrology and natural phenomena including geology.
... These factors could affect the species composition and the organisms were found to be species-specific according to the environmental factors. Spatial patterns of diatom species assemblages and environmental factors effecting diatom species communities have been targeted in several studies (Biggs, 1990;Pipp and Rott, 1994;Reavie and Smol, 1998;Rott et al., 1998;Pan et al., 1999;Potapova and Charles, 2003;Soininen, 2002). ...
... Organic pollutants that are discharged into rivers can, through oxidation, be converted into nutrients that support algal growth. Other studies have also found that COD plays an important role in diatom patterns in highly disturbed areas [50,51]. Similar to most other studies [52,53], TN was shown to have important effects on diatom patterns in the Chishui river. ...
Benthic algae, especially diatoms, are commonly used to assess water quality in rivers. However, algal-based assessments are challenging at the river system scale because longitudinal variation in physical habitat conditions may obscure algal responses to changes in water quality. In the present study, we surveyed benthic diatoms and environmental variables from a mountainous Chinese river system. Hierarchical clustering, discrimination analysis, and indicator species analysis were used together to explore associations between distribution patterns of diatom assemblages and water quality variables. Study sites were clustered into five groups based on their diatom community composition, with sites grouped by the sampling months. Chemical oxygen demand (COD), elevation, and total nitrogen (TN) were the most important predictors for site classification. Site groups with higher elevations had higher TN concentrations; however, COD concentrations were higher in lower elevation groups. Moreover, COD concentrations significantly differed between temporally separated groups. In total, 49 indicator species were identified for individual groups, with most taxa indicating the eutrophic condition. Additionally, we found that European diatom indices are not closely associated with water quality variables. We conclude that the identification of algal patterns and their driving forces can provide valuable information to aid bioassessment at the river system scale.
... The urban environmental health can be determined by analysis of pollutants, by satellite methods or analysis of plant communities (Priso et al., 2000;Markert et al., 2003). The study of aquatic organisms provides an analysis that integrates the contamination of ecosystems because their presence or abundance reflects the successive environmental conditions that have occurred during their development (Jüttner et al., 1996;Soininen 2002;Beyene et al., 2009). The objective of this study is to show the influence of urban pollutant released from of various origins on the distribution of aquatic macrophytes and the pollution gradient of three Mfoundi tributaries. ...
The Mfoundi watershed serves as a collector of untreated sewage in the Yaounde urban area. This study on the floristic diversity of this ecosystem was conducted with the objective of determining the influence of water pollution on the distribution of the subservient macrophytes. The inventory based on floristic records from BraunBlanquet abundance-dominance coefficients was carried out in 90 plots of 5 m x 5 m distributed over 9 stations belonging to 3 tributaries (Aké, Biyeme, Ewoué) chosen on the basis of the effluents they receive. The R version 3.3.3 software was used to analyze the data. The Shannon diversity index, which ranges from 2.64 to 3.32, is indicative of a richness of floristic diversity in the Mfoundi lowlands. However, they are dominated by Pennisetum purpureum Schumach. (14.9%), Commelina benghalensis L. (9.3%) and Echinochloa pyramidalis (Lam.) Hitchc. & Chase (8.4 %). On each tributary studied, Ipomoea aquatica Forsk. abundantly appears at the intermediate level and disappears downstream. Other abundant species (Hydrolea glabra Schumach & Thonn, Leersia hexandra Sw. and Pistia stratiotes L.) have a fortuitous and evanescent appearance, approaching the above-mentioned specie but subservient only to the Aké tributary. These abundant species can give an indication of the quality of the water and guide the ecological restoration of degraded environments.
... Between 1996 and 2001, diatoms were sampled from 141 sites, comprising the five ecoregions in Finland and covering broad gradients in conductivity, pH, humic content and nutrient concentrations ) (see Appendix Table S1 in Supporting Information). Sites are described in detail by Soininen (2002) and . The second data set comprised 56 fast-flowing rivers in central Finland sampled in 1986 by . ...
The ongoing climate change and increasing anthropogenic pressure threaten the biodiversity on Earth. Elevated temperatures, changes in precipitation and intensive land use alter ecosystems and such changes are prone to escalate in the northern regions, especially in freshwater ecosystems. Species must thus respond to these changes by adaptation or adjusting their distributional ranges. Information about the effects of climate on the distributional patterns of diverse aquatic micro-organisms has yet largely been lacking. This is a drawback as microbial species in freshwaters play crucial roles in ecosystem functioning as well as in environmental monitoring. Thus, it is necessary to disentangle the main drivers of microbial species distributions in order to predict the responses of freshwater communities to future environmental change and to ensure the accurate determination of the ecological status of ecosystems.
This doctoral thesis aims to investigate the relative roles of climate, catchment properties and local environmental factors in the occurrence of the important freshwater micro-organisms both at species and community levels. This study, conducted at a regional scale (c. 1000 km), concentrates on unicellular stream diatoms, which are widely used in biomonitoring. In detail, the study seeks to reveal (1) whether diatom species distributions are influenced by climatic factors or solely driven by local environmental variables, (2) whether the importance of the factors governing species distributions varies along the anthropogenic land use gradient, (3) the pathways and the effects of climate, land use and the most important local environmental variables on diatom diversity and community composition, and (4) the ability of diatom assemblages to predict climatic and local environmental variables.
The results showed that climatic factors are important drivers of stream diatom distributions and their influence may even outcompete the effects of local environmental variables. However, the relative importance of the factors governing diatom distributions varied along the anthropogenic land use gradient and among species. Climate was the main driver of species distributions in pristine environments, whereas local environment was more important in human impacted streams. Climatic and catchment scale factors affected stream diatoms mainly via indirect pathways, for example, through catchment productivity and nutrient availability. Species richness was mainly influenced by energy and nutrient availability. Conductivity, which was strongly related to anthropogenic land use, was a key factor influencing community composition and uniqueness, but also species distributions especially in human impacted streams. Unique communities with high conservation value and low species richness were detected in harsh, low-nutrient conditions in northern Finland.
Diatom assemblages were also found to be reliable predictors of both climatic and local environmental factors indicating their robustness as environmental proxies and bioindicators. Highly suitable indicator species were identified for water chemistry variables but also for certain climatic conditions.
This thesis contributes to the spatial research of aquatic micro-organisms as it brings a novel evidence of the biogeographical patterns of microbial species. This study revealed that climate, one of the fundamental drivers of species distributions on Earth, governs also the occurrences and abundances of stream diatoms even at regional scales. However, it is important to acknowledge that the effects of the most essential climatic and environmental factors influencing diatom species may be context dependent and vary along the anthropogenic land use gradient. The ongoing climatic and subsequent environmental change may further complicate the species responses towards environmental factors. From an applied perspective, this study confirmed the reliability of stream diatom assemblages as bioindicators. However, diatom responses towards novel environmental conditions need to be reevaluated to assure their accuracy also in the future.
... The European Water Framework Directive (WFD) has listed diatoms as indicators for some time (European Union, 2000). Researchers from the United States (Nelson et al., 1976;Potapova and Charles, 2007) and Japan (Goto et al., 2007) also recommended benthic diatoms as an appropriate approach in monitoring of eutrophication and plenty of diatom indices were proposed and successfully applied, such as the Biological Diatom Index (IBD, Prygiel and Coste, 2000), the Specific Pollution Index (IPS, CEMAGREF, 1982), the Trophic Diatom Index (TDI, Kelly and Whitton, 1995), and the Diatom-based eutrophication/ pollution Index (EPID, Dell'Uomo, 1996) (Soininen, 2002;Tan et al., 2013). ...
... Group D9 collects sites from Istra, the largest Croatian peninsula that differs from the rest of Croatian coast (Prelogović et al. 1995), consisting of upper reaches of small karstic streams and a few continental streams. Although differing signifi cantly, they share a species Nitzschia palea (Kützing) W.Smith, commonly reported from sites affected by agriculture and industry (John 2002, Soininen 2002. Therefore, group D9 encompasses streams affected by high artifi cial nutrient load. ...
Benthic diatoms are widely used in Europe and worldwide to access ecological status of running
waters. One of key goals of Water Framework Directive is to classify rivers and streams using biological
quality elements and type specifi c reference conditions. According to system B which incorporates additional
abiotic descriptors, there are 24 water types in Croatia. For biological analyses 92 rivers and streams with 140
sampling points were chosen and sampled for benthic diatoms and water chemistry simultaneously. Self organizing
map (SOM) analysis was used to defi ne biotypes from species composition and abundance of benthic
diatoms. Grouping of samples in SOM resulted in 10 distinctive groups. Based on their geographical position
and site characteristics, groups represent sites with similar properties (as waterbed, catchment size, altitude,
size of stream) belonging to different ecoregions in Croatia. Analysis of variance revealed statistically signifi -
cant differences (p<0.05) among SOM groups concerning ammonia, nitrates and total phosphorus. Indicator
species analysis (IndVal) singled out species that were signifi cantly characteristic (p<0.05) for SOM and abiotic
types. Compared to abiotic groups, in which 7 out of 24 have no indicator species, all SOM groups have
one or several characteristic diatom species, thus indicating diatom assemblages as valuable site descriptors.
Canonical analysis of principal coordinates analysis also indicated that SOM grouping of samples is statistically
reliable. Grouping of similar sites, although placed into different abiotic types, makes SOM groups with
its corresponding representative species an easy tool for water quality assessment and description of reference
assemblage.
... gracilis, Achnanthes minutissima, and Tabellaria flocculosa, all very common diatoms in oligotrophic northern rivers (e.g. Soininen 2002, Niemelä et al. 2002, Miettinen 2006. Detailed species lists are available at www.triwa.org. ...
The legislation and administrative systems in Finland and Sweden are very similar. There are no major differences, but in some issues, for example in forest drainage or construction in or close to the shore area, the procedures and legislation have somewhat different approach. On the other hand, in water management, the interpretation and implementation of the common Water Framework Directive have differences that inn uence the cooperation across the border. People's opinion on and wishes for cooperation across border were surveyed. Even though the public participation systems are well developed both in Finland and Sweden, people feel that they are not necessarily heard in water management issues, or that their opinions are not taken into account in decision making. There is a genuine wish and need for cooperation across the border in Torne River area. Especially informal participatory processes need developing. Earlier developed typologies for rivers and lakes of Torne River area were tested with fish (lakes) and phytobenthos (rivers). The results supported the typologies. Simultaneously, national classii cations of the ecological status were tested. It became clear that harmonization of national indices is necessary, as the evaluation of the ecological state using sh analysis gave very different results depending on the system used. With phytobenthos, the results were very close to each other. It is obvious that the evaluation systems have to be tested and carefully chosen for the region. It also seems that the earlier suggestions for simplii ed typologies are usable in the area. ISBN 978-952-11-3041-0 (pbk.) ISBN 978-952-11-3042-7 (PDF)
... The European Water Framework Directive (WFD) has listed diatoms as indicators for some time (European Union, 2000). Researchers from the United States (Nelson et al., 1976;Potapova and Charles, 2007) and Japan (Goto et al., 2007) also recommended benthic diatoms as an appropriate approach in monitoring of eutrophication and plenty of diatom indices were proposed and successfully applied, such as the Biological Diatom Index (IBD, Prygiel and Coste, 2000), the Specific Pollution Index (IPS, CEMAGREF, 1982), the Trophic Diatom Index (TDI, Kelly and Whitton, 1995), and the Diatom-based eutrophication/ pollution Index (EPID, Dell'Uomo, 1996) (Soininen, 2002;Tan et al., 2013). ...
An annual investigation on periphytic diatoms and physicochemical parameters was performed in Donghu Lake, China, to explore a suitable method to differentiate the dominant and subordinate taxa, and how they responded to the change of environmental factors. The results showed that: (1) a combined consideration of species frequency of occurrence and relative abundance for defining the dominant index was more appropriate than using solely relative abundance; (2) the dominant taxa Fragilaria capucina var. vaucheriae (Kützing) Lange-Bertalot and Melosira varians Agardh responded insensitively to the environmental factors, whereas the subordinate species Fragilaria capucina Desmazieres var. capucina, Nitzschia amphibia Grunow, Achnanthidium exiguum (Grunow) Czarnecki and Melosira italica (Ehrenberg) Kützing showed the potential to be indicators; F. capucina var. radians (Kützing) Lange-Bertalot increased along the gradient of higher water temperature (WT) and nutrients concentration, however, Fragilaria bidens Heiberg and Cymbella affinis Kützing were affected in the opposite direction. Our findings revealed that periphytic diatoms varied seasonally and were useful for assessing water quality of different trophic status. Especially the subordinate species showed the potential to be better indicators than the dominant species in Donghu Lake.
... Between 1996 and 2001, diatoms were sampled from 141 sites, comprising the five ecoregions in Finland and covering broad gradients in conductivity, pH, humic content and nutrient concentrations (Soininen et al., 2004) (see Appendix Table S1 in Supporting Information). Sites are described in detail by Soininen (2002) and Soininen et al. (2004). The second data set comprised 56 fast-flowing rivers in central Finland sampled in 1986 by Eloranta (1995). ...
1. Benthic diatoms have been widely used as indicators of water quality in streams as diatom assemblages reflect local environmental conditions. It has recently been shown that diatoms may also respond to large-scale drivers such as climate or historical factors highlighting the need to further assess the usefulness and the reliability of diatoms as bioindicators.
2. We used weighted averaging (WA), weighted averaging partial least squares (WA-PLS), modern-analogue technique (MAT) and two machine learning techniques, boosted regression trees (BRT) and random forests (RF), to infer water quality and climate from diatom abundance data collected from 227 stream sites in Finland (60˚ – 70˚ N).
3. The highest relationship between diatom-inferred and observed values was found for a climatic variable, namely growing degree days, GDD (r2 = 0.86, MAT). The predictive ability was also excellent for conductivity (r2 = 0.82, RF). Moreover, we found that the predictive ability of models was generally better for climatic variables (GDD, summer precipitation and water balance) than for local environmental variables (conductivity, water colour and total phosphorus). Using BRT, we also identified species having the highest relative importance in the models as potential indicator species for local environmental and climatic variables.
4. Our results indicate that diatoms could serve as efficient proxies at multiple scales: for local environmental conditions and also for climatic variables. We conclude that new modelling techniques such as modern regression trees can provide new insights into relationships between diatom assemblages and local water quality and climate, and thus help to create more reliable indices. These methods could also serve as important tools to infer environmental variables in changing ecosystems.
... In Hood Brook, 79% of the community consisted of diatoms and the most abundant species was Eunotia sp.1. The genus Eunotia is extensively referred to in the literature as an acidobiontic form (WINTERBOURN et al., 1985;MULHOLLAND et al., 1986;LEDGER & HILDREW, 1998;LEDGER & HILDREW, 2000) and has been reported as characteristic of humic waters (SOININEN, 2002). Cluster analyses using individual stones (Fig.2), showed that the between-stream variation was greater than the between-stone variation within each stream. ...
Differences in epilithic algal community characteristics between streams on diverse geological substrata were investigated. Four streams in the Peak District, Derbyshire, UK, were sampled, two on carboniferous limestone with circumneutral waters and two on millstone-grit, with intermittently acid waters. The streams were sampled in March and April 2000, and the composition of the algal community on 20 stones from each site was studied using light microscopy. Five stones from each site were also collected for extraction of epilithon DNA. The DNA was amplified using universal primers for phototrophs, followed by DGGE (denaturing gradient gel electrophoresis). The Peak District epilithic algal communities were found to be grouped into two types, according to geological substratum. Algal abundance was higher in the limestone streams, and so was cyanobacterial and diatom species richness. The number of bands obtained on the DGGE gels was less than the species richness found in the microscopic analysis. Nevertheless, this approach was useful in revealing between-stream differences. The study showed that epilithic algal communities in streams have the potential to reflect broad landscape features, such as geological substrata.
... Benthic diatoms are often used for assessing environmental conditions, such as water quality and habitat conditions in stream and river systems and nutrient enrichment (e.g. Pan et al., 1999;Soininen et al., 2004;Kelly et al., 1995;Rott et al., 1997Rott et al., , 1999Coring, 1999) and have been widely related to specific environmental conditions in different geographical regions (Soininen, 2002;Martinez De Fabricius et al., 2003;Ndiritu et al., 2006;Gómez and Licursi, 2001;Lobo et al., 2002Lobo et al., , 2004a. Consequently, several studies have addressed the tolerances and preferences of diatoms along a number of environmental gradients, such as gradients in salinity, pH, trophy, saprobity and current preference (e.g. ...
... The River Continuum Concept (Vannote et al. 1980) has provided a stimulating theoretical framework for the research on ecological structural properties in running water systems (Hynes 1970;Junk 1999;Stanford & Ward 1988). Spatial patterns of diatom species assemblages and environmental factors driving diatom species communities have been targeted by several studies (Biggs 1990;Pipp & Rott 1994;Reavie & Smol 1998;Rott et al. 1998;Pan et al. 1999Pan et al. , 2000Potapova & Charles 2003;Soininen 2002). These studies highlight the dominant role of chemical constituents and ion composition in the shaping of the structures of diatom communities (Johansson 1982;Soininen 2004). ...
A total of 322 benthic diatoms with the majority being cosmopolitan species was recorded during a survey of the catchment area of the Kebir-East wadi, northeast Algeria. The spatial distribution patterns of diatom communities in relation to environmental gradients were examined using Co-Inertia Analysis (CIA) for ascertaining the interdependence between physico-chemical descriptors and diatom assemblages in 182 samples, collected over a period of 3 years, across 23 sampling stations. There was a significant covariance between the environmental data set and the benthic diatom data set with the CIA highlighting correlations between environmental factors and diatom species. A clear longitudinal gradient was a main driver of diatom communities with upstream sites characterized by high dissolved oxygen concentrations and downstream sites characterized by high organic load and nutrient enrichment of the water. A further factor influencing the shape of diatom assemblages was related to the conductivity, and the high values possibly reflected the close proximity of the sea to the downstream sites. An anthropogenic impact was also most evident in structuring diatom assemblages at sites close to Lake Oubeïra where agriculture was concentrated.
... Periphyton, which constitutes the basis of aquatic food webs (Vannote et al. 1980;Szabo et al. 2008), strongly depends on physical habitat characteristics (Soininen 2002;Mu¨llner & Schagerl 2003). This is supported by our data where most physicochemical variables revealed significant correlation with periphyton community composition. ...
Most of the world’s rivers are affected by dams and weirs, which results in modifications of serial continuity and declines of riverine fish species. Information on the quantitative and qualitative effects of weirs as well as on the efficiency of restoration measures is crucial for successful management of stream ecosystems. We developed and tested an evaluation system for the quantification of weir-introduced serial discontinuity and for an assessment of the ecological functionality of fish passes. Weir-induced effects exceeded the effects from variation of geographic location, geology, and drainage system. The effects were quantified concerning abiotic habitat properties as well as in the community structures of fishes, macroinvertebrates, macrophytes and periphyton. In addition to their roles as migration corridors, fish passes provided important key habitats for juvenile and small rheophilic fishes. Consequently, fish passes can play an important role as compensatory habitats and this function should be better considered in river restoration. The evaluation system presented herein, by including several taxonomic groups and physicochemical habitat variables, provides a universally applicable tool for the ecological assessment of serial discontinuity and its mitigation.
... The compositions of epilithic diatom communities in rivers have been frequently related to specific environmental conditions because diatom species are sensitive to such conditions and because (1) they are usually the dominant autotrophic group in rivers and (2) identifying diatom species is simpler than identifying other taxa (such as cyanobacteria and Chlorophyceae), making them effective at assessing water quality (Round 1993;Soininen 2002;Ndiritu et al. 2006;Urrea & Sabater 2009). Round (1993) also gave more specific reasons for using diatoms to monitor changes in river water quality, stating that: ...
Epilithic diatom communities were sampled every two weeks from February 2001 to February 2002 at three sites in the lower Han River (LHR), South Korea, to investigate how epilithic diatom communities reflected longitudinal gradients in environmental quality measures. The water quality in the LHR differed between the rainy and dry seasons and also varied at different sites according to levels of pollution. The epilithic diatom communities responded to changes in the aquatic environment and hydrological characteristics. There were few predominant diatom species during the rainy season, and they were found at lower concentrations than in the dry season because of the high current velocities caused by heavy rainfall. The predominant species at the three study sites in the LHR were different because of the effects of eutrophication gradients. Cocconeis placentula, Diatoma vulgaris, and Nitzschia dissipata were dominant at site 1 (clean to nutrient-rich conditions). Fragilaria capucina var. gracilis and Gomphonema parvulum were dominant at site 2 and their growth was accelerated by the moderately-nutrient-rich conditions. Luticola goepperitnana, N. palea, small Nitzschia spp., and small Navicula spp. were dominant in the most polluted pools at site 3. We conclude that the LHR has a water quality gradient along its course, and that this causes marked changes in the epilithic diatom species compositions found along the river. The results confirm that epilithic diatoms are important bioindicators for assessing ecological quality in the LHR.
... In contrast to other studies on polluted streams (Kawecka, 1977;Silva-Benavides, 1996;Soininen, 2002), pollution tolerant Nitzschia species were less common than would have been expected, whereas Navicula species were more abundant. However, most streams in the KV were enriched by agricultural runoff and only a few streams were within densely populated city areas and seriously affected by sewage. ...
... The effects of local environmental factors on diatom communities were of less importance as study extent increased, however (Soininen, 2007). Strong spatial components occur on a large scale (national scale) for diatom communities (Soininen, 2004) and regional classifications based on terrestrial landscape offered a good framework for diatom communities of Finnish rivers , and this should be taken into account in diatom bioassessment tools (Soininen, 2002). Other methods, for example self-organizing maps, were used to define reference diatom communities in different French regions or Quebec . ...
The first studies of diatoms and river pollution were carried out 60 years ago, and the suitability of these micro-algae as bioassessment indicators for monitoring river quality was quickly demonstrated. The objective of this review is to describe the state of the art of the study of diatoms and river pollution between 1999 and 2009. The objective was to group the publications homogeneously according to subject and to indicate which subjects never overlap. To this end a lexical analysis was conducted on the abstract structure of these publications and seven K-means clusters were defined. Most of the items in this area were found to have been published in Hydrobiologia. One group (group 6) comprises publications about a discipline (ecotoxicology); several others group publications on the basis of the same approaches, for example species (group 3), basin (group 7), or spatial approaches (group 2). Other publications are brought together because the studies used a common method of using data, namely predictive models (group 1) or biotic indices (group 4). One group of publications was of studies performed in the same area—South Africa (group 5). Several remarks can be made. First, ecotoxicological studies are mostly experimental and restricted to small study areas. To answer society’s demand for new assessment tools for micropollutant assessment, the next step would be to have more in-situ tests on larger spatial scales. Second, diatom biomonitoring uses the word “species” extensively, because this is the basis for establishing the lists of flora which are used extensively in such subject areas. Species is closely related to taxonomy; nevertheless this discipline is very rarely addressed in the papers. Third, phylogeny is never addressed in the publications. This is significant because phylogenetic studies for freshwater macroinvertebrates enable appropriate definition of taxonomic aggregations that can be used as accurate indicators of particular environmental stressors.
... The occurrence of algal biomass in river systems depends on a number of chemical variables, including nutrient availability (Welch and Patmont, 1989;Veraart et al., 2008) and other geochemical properties of the water, such as pH (Soininen, 2002). Physical and habitat variables such as canopy cover (Mosisch et al., 2001), turbidity (Munn et al., 1989), water temperature ( Morin et al., 1999) and hydrologic disturbances (Powers, 1992;Biggs, 1995;Bertrand et al., 2001;Riseng et al., 2004) can also affect algal production and biomass. ...
... Although extensive research into the impacts of eutrophication on diatoms has already been performed in lowland rivers and lakes (e.g. Lowe & McCullough 1974, Rott et al. 1998, Soininen 2002, Potapova et al. 2005, Camargo & Jiménez 2007 ), mountain stream assemblages have received much less attention. Algae from low order mountain streams, however, respond much more rapidly to pollution in comparison with algae from larger streams (Rott et al. 2006 ), and therefore they can quickly indicate actual environmental changes. ...
Background and aim - Mountain streams represent sensitive ecosystems of prime importance for biodiversity conservation. However, the knowledge of the impact of sewage pollution related to intensive recreational exploitation is still limited in these habitats. Our aim was to assess the response of stream diatom assemblages to sewage pollution in the Giant Mountains and the Bohemian Forest, and to find the main factors influencing the community structure. Methods - Epilithic samples from sixteen streams were collected, both in unaffected stream sections and at sites downstream of sewage outflows from mountain cottages or small villages. Basic physical and chemical parameters were measured and relative abundances of diatoms were determined using light microscopy. Key results - A total number of 153 diatom taxa belonging to 44 genera were identified. Based on species data, samples were divided into two groups: the first belonged mainly to sites influenced by pollution, whereas the second consisted of not or slightly affected sites. Both groups were further divided into several subgroups characterised by specific ecological conditions and assemblage composition. Canonical correspondence analysis (CCA) revealed five environmental parameters with significant influence on diatom species composition, some of which were related to sewage pollution (pH, water temperature, discharge volume and concentrations of nitrate nitrogen and organic nitrogen). Conclusions - As a consequence of sewage pollution, oligo- to mesotraphentic taxa were outcompeted by pollution tolerant taxa. However, pollution had no significant influence on diatom diversity, which was similar at sites both upstream and downstream of the outflows. In this study, diatom assemblages performed well as indicators of sewage pollution, and biomonitoring proved to be a useful tool in the detection of environmental stress in mountain streams. Overall, the response of diatom assemblages showed that an increase of recreational activities might significantly alter the ecological status of these ecosystems.
Over the last few decades, the studies on the factors of climate change viz. temperature, carbon dioxide etc. and their impact on different ecosystems have been gaining importance, as they are threatening the ecological balance. The most immediate effect of change in climate is expected to be seen in water bodies with change in temperature affecting their pH, salinity, solubility, diffusion rate and viscosity. Water acidification due to rise in CO2 concentration, and nutrient load (eutrophication) as a result of anthropogenic activities are the major forces which are expected to have negative impact on water quality. They modify the structure, function and algal diversity (toxic or nontoxic- harmful algal blooms), having detrimental effects on the aquatic ecosystems. Algae (Latin- alga, seaweed), the diverse group of photosynthetic eukaryotic, unicellular or multicellular organisms (kingdom Protista), can be found in vast habitats including rivers, streams, lakes, oceans and other exclusive habitats like ice or snow, thermal vents, and also in terrestrial ecosystems. Besides being used as a food and a substrate for biofuel production, they possess characteristics like rapid reproduction rates, short life cycle, sensitivity and ability to accumulate pollutants, and responsiveness to natural or environmental disturbances at spatio-temporal scales, which qualify them as one of the biological indicators for changing climate. There are several species of algae which respond to the change in environmental factors, and some of them are used as indicators of change. Besides being the indicators, the large-scale production of algal foods and biofuels also have a significant impact on global energy requirements and greenhouse gas emissions. Algae as indicators of climate change have been studied only in few locations and started very recently, so without the past knowledge, the present and the future effects are very difficult to quantify.
Over the last few decades, the studies on the factors of climate change viz. temperature, carbon dioxide- CO2 etc. and their impact on different ecosystems have been gaining importance, as they are threatening to the ecological balance. The most immediate effect of change in climate is expected to be seen in water bodies with change in temperature affecting their pH, salinity, solubility, diffusion rate and viscosity. Water acidification due to rise in CO2 concentration, and nutrient load (eutrophication) as a result of anthropogenic activities are the major forces which are expected to have negative impact on water quality. They modify modify the structure, function and algal diversity (toxic or nontoxic- harmful algal blooms), having detrimental effects on the aquatic ecosystems. Algae (Latin- alga, seaweed), the diverse group of photosynthetic eukaryotic, unicellular or multicellular organisms (kingdom Protista), can be found in vast habitats including rivers, streams, lakes, oceans and other exclusive habitats like ice or snow, thermal vents, symbiotic, as epiphytes and also in terrestrial ecosystems. Besides being used as a food and for biofuel production, they possess characteristics viz. rapid reproduction rates, very short life cycle, sensitivity and ability to accumulate pollutants, and responsiveness to natural or environmental disturbances at spatial and temporal levels, which qualify them as one of the biological indicators for changing climate. There are several species of algae which respond to the change in environmental factors, and some of the species which are used as the indicators of change. Besides being the indicators, the large scale production of algal foods and bio-fuels also have significant impact on global energy requirements and greenhouse gas emissions. Algae as the indicators of climate change have been studied only in few locations, and started very recently, so without the past knowledge, the present and future effects are very difficult to quantify.
Periphytic algae is a useful indicator of aquatic ecological conditions. We investigated the periphytic algae on natural substrate and the environmental variables at 44 sites on three river systems in the Weihe River Basin (WRB). A total of 84 species are identified, representing 37 genera. The most common genera were Navicula, Oscillatoria, Nitzschia, Scenedesmus, Cymbell, and Fragilaria. One-way analysis of variance (ANOVA) indicated significant differences among the three river systems in environmental variables (p < 0.05). Non-metric multidimensional scaling (NMDS) analyses also showed differences in periphytic algae communities in the three river systems (p < 0.05) and identified different dominant species in each river system. Canonical correspondence analysis (CCA) and Monte Carlo permutation tests revealed that nutrient concentration, WT, and altitude were the most important variables affecting the structure and distribution of periphytic algae communities. Chemical variables were the most accounted for environmental variables (12.5%), while physical variable and geographical factors (5.8% in total) play a relevant minor role. Our results demonstrate that Navicula pupula, Navicula radiosq, Nitzschia palea, and Nitzschia denticula, exhibiting wide ecological amplitude, are tolerant of high concentrations of nutrient pollution. Variation of periphytic algae communities in WRB is due to the combination of anthropogenic and natural factors including agricultural and domestic wastes water inputting, land use patterns, geology, climatic changes, and river hydrology. HIGHLIGHTS
Structure and distribution of periphytic algae communities were investigated in the Weihe River Basin.;
The gradient of organic pollution detected in environmental variables was the main gradient, and the periphytic algae responded to this gradient.;
The types of substrates in river impact periphytic algae abundance, causing higher periphytic algae abundance in cobbles substrate.;
The variation of periphytic algae communities is attributed to the combination of anthropogenic factors and natural factors.;
The results support the periphytic algae as ecological indicators in the Weihe River Basin.;
The species richness and community composition of the diatom communities were studied in the Baltic Sea, Northern Europe, to enhance knowledge about the diversity of these organisms in a brackish water ecosystem. Many organisms in the Baltic Sea have been studied extensively, but studies investigating littoral diatoms are scarce. The goal of this study was to examine the importance of climatic, spatial and water physicochemical variables as drivers of epilithic diatoms in the Gulf of Finland and the Gulf of Bothnia. The variation in species richness was best explained by pH, total phosphorus and total nitrogen. Redundancy Analysis indicated that the most important factors correlating with species composition were air temperature, silicon, total phosphorus, water temperature, salinity and pH. Variation Partitioning showed that the species composition was mostly affected by climatic and spatial variables, whereas physicochemical variables had little impact. However, the strongest factor was the combined influence of climatic, spatial and physicochemical variables. The results suggest that diatom species richness in the northern Baltic Sea is primarily regulated by local factors, while climatic and spatial variables have little impact on richness. Species composition is mostly affected by climatic and spatial variables. We conclude that understanding the distribution patterns of Baltic Sea diatoms requires the inclusion of climatic, spatial and water chemistry variables.
Predicting the composition of benthic macroinvertebrate fauna in rivers is not a trivial task, both because of the number of species to be modelled and because of the complexity of biotic and abiotic relationships that determine their distribution. However, the composition of the benthic macroinvertebrate fauna usually provides very useful insights into the ecological quality of lotic systems, as these organisms are very sensitive to disturbance. Benthic macroinvertebrates are relatively sedentary and long-lived, with life cycle durations ranging from a few months to 2-3 years, and they show a wide range of adaptations to local environmental conditions. They represent a continuous monitoring system of the water body where they are living, but they are also very easy to collect and to identify, at least at an intermediate taxonomic level. Therefore, benthic macroinvertebrates are widely used as biological indicators (Hellawell 1986) and, in particular, they have been used for many years as a source of information for computing several biotic indices that are now used worldwide to assess biological water quality (e.g., Metcalfe 1989, Resh et al. 1996, Lammert and Allan 1999). In this study, the Italian IBE index (Ghetti 1997), derived from the Extended Biotic Index proposed by Woodiwiss (1981) was used as a reference for selecting ecologically homogeneous taxa. Several different biotic indices have been developed, as they had to be suited to ecoregional characteristics in order to provide correct diagnoses of the riverine ecosystem quality. Most indices, however, share the same rationale that is based on the identification of sensitive taxa and on the recognition of the ecological role of other taxa. The main advantage of this approach with respect to more thorough community structure analyses lies obviously in its simplicity. In fact, even people with a limited taxonomic background can be easily trained to carry out rapid surveys aimed at the computation of biotic indices. A more complex approach to the assessment of the ecological status of streams and rivers is based on the prediction of the whole community structure. In the case of benthic macroinvertebrate fauna, different modelling techniques based on ecological knowledge and monitoring data are now available. In the United Kingdom, the work by Wright et al. (1984) led to the prediction of community types on the basis of environmental data by means of a multivariate analysis procedure. This appraoch was then extended and used in the River Invertebrate Prediction and Classification System (RIVPACS) (Wright et al. 1993b), which provides estimates of the ecological quality at a given site by comparing the observed macroinvertebrate fauna composition with the expected one. The RIVPACS approach has also been adapted to other ecoregions. For instance, the Australian River Assessment Scheme (AUSRIVAS) (Simpson and Norris 2000) is based on the RIVPACS approach, although it has been expanded and adapted to each Australian ecoregion. Another method that is closely related to RIVPACS and AUSRIVAS is the benthic assessment of sediment (BEAST) (Reynoldson et al. 1995), that is based on quantitative data about macroinvertebtare fauna instead of presence/absence data only. Even though the RIVPACS approach proved to be very effective, it has limits related to the non-linearity, complexity and dynamic nature of biotic responses to environmental characteristics. Moreover, the development of an assessment system based on the RIVPACS rationale requires a considerable amount of work and thorough statistical analyses. A new generation of empirical techniques for analysing and modelling complex ecological data in a more simple and straightforward way is now emerging. Among these new modelling methods Artificial Neural Networks (ANNs) play a relevant role and represent a useful tool when relationships among data are unknown and/or non-linear. ANNs learn from examples and do not require a priori theoretical models, nevertheless they are able to model complex temporal and spatial patterns and to reproduce the behaviour of very complex systems (Recknagel and Wilson 2000). During the last 10 years, ANNs have been applied to various ecological fields (see, for instance, Lek and Guegan 2000), including studies relating community characteristics with environmental variables (e.g., Chon et al. 1996, Recknagel 1997, Recknagel et al. 1997, 1998, Guégan et al. 1998) and modelling habitat suitability (e.g., Paruelo and Tomasel 1997, Ozesmi and Ozesmi 1999). As for the particular case of macroinvertebrate fauna, Pudmenzky et al. (1998) and Walley and Fontama (2000) recently developed ANN approaches that are aimed at the same goals and ecoregions as AUSRIVAS and RIVPACS respectively. Our study was focused on a benthic macroinvertebrate data set provided by the Latium Regional Environmental Protection Agency and it is aimed at testing different strategies for modelling the presence or absence of macroinvertebrate benthic taxa on the basis of environmental variables, using ANN models.
Epipelic diatoms and some physico-chemical features of Tortum streams were studied in the samples collected montly from four sampling-stations during June 2005-February 2006. A total of 113 taxa of epipelic diatom were determined. According to cluster analysis, dominant diatom species constituted two groups (eutrophic and polluted). Cocconeis placentula var. euglypta in I. group (eutrophic) and Nitzschia palea ve Navicula cryptocephala in II.group (polluted) were established to be the most explicit dominant species. N. palea and N. cryptocephala were correlated positively with nutrient concentrations. Significant correlation was found between C. placentula var. euglypta and conductuvity. The composition of dominant taxa and results of chemical analysis indicated that Tortum streams was organically polluted.
Diatom and water samples were collected from 145 river sampling stations in Finland. The relationship between benthic diatom taxa and measured environmental variables was explored using canonical correspondence analysis (CCA). A weighted averaging (WA) regression model was developed to infer phosphorus concentrations of river water. The optima and tolerances of the diatom species were obtained from the WA regression. The performance of the WA model was assessed using correlation coefficients and the root mean squared error of prediction (RMSEP) between the observed and inferred phosphorus concentrations. The model was cross-validated using an independent test set. The predictive power of the WA model was good (r = 0.91; RMSEP 13.9 μg P/l) in the training set. The weighted averaging also performed well in the independent test set (r = 0.87; RMSEP 15.6 μg P/l). The correlations were only slightly lower and predictive errors larger than in the training set. The weighted averaging gives a tool to evaluate trophic conditions in different ecoregions with the species optima list suitable for prevailing conditions and water quality.
Atmospheric deposition of reactive nitrogen (Nr) has enriched oligotrophic lakes with nitrogen (N) in many regions of the world and elicited dramatic changes in diatom community structure. The lakewater concentrations of nitrate that cause these community changes remain unclear, raising interest in the development of diatom-based transfer functions to infer nitrate. We developed a diatom calibration set using surface sediment samples from 46 high-elevation lakes across the Rocky Mountains of the western US, a region spanning an N deposition gradient from very low to moderate levels (<1 to 3.2 kg Nr ha−1 year−1 in wet deposition). Out of the fourteen measured environmental variables for these 46 lakes, ordination analysis identified that nitrate, specific conductance, total phosphorus, and hypolimnetic water temperature were related to diatom distributions. A transfer function was developed for nitrate and applied to a sedimentary diatom profile from Heart Lake in the central Rockies. The model coefficient of determination (bootstrapping validation) of 0.61 suggested potential for diatom-inferred reconstructions of lakewater nitrate concentrations over time, but a comparison of observed versus diatom-inferred nitrate values revealed the poor performance of this model at low nitrate concentrations. Resource physiology experiments revealed that nitrogen requirements of two key taxa were opposite to nitrate optima defined in the transfer function. Our data set reveals two underlying ecological constraints that impede the development of nitrate transfer functions in oligotrophic lakes: (1) even in lakes with nitrate concentrations below quantification (<1 μg L−1), diatom assemblages were already dominated by species indicative of moderate N enrichment; (2) N-limited oligotrophic lakes switch to P limitation after receiving only modest inputs of reactive N, shifting the controls on diatom species changes along the length of the nitrate gradient. These constraints suggest that quantitative inferences of nitrate from diatom assemblages will likely require experimental approaches.
Ecosystem services would be incorporated into decision making more often if researchers were to focus more on the demand for these services rather than the supply. This implies examining the economic, decision making and technological context of the end-user before trying to attribute economic values to well known biological processes. This paper provides an example of how this research approach for ecosystems services could unfold. In the Llobregat River in northeastern Spain, higher stream temperatures require water treatment managers to switch on costly water treatment equipment especially during warm months. This creates an opportunity to align the economic interests of downstream water users with the environmental goals of river managers. A restored riparian forest or an increase in stream flow could reduce the need for this expensive equipment by reducing stream temperatures below critical thresholds. We used the Stream Network Temperature Model (SNTEMP) to test the impact of increasing shading and discharge on stream temperature at the intake of the drinking water treatment plant. The value of the stream temperature ecosystem services provided by existing forests is €79,000 per year for the water treatment facility, while additional riparian forest restoration along the Llobregat River could generate economic savings for water treatment managers in the range of €57,000–€156,000 per year. Stream restoration at higher elevations would yield greater benefits than restoration in the lower reaches. Moderate increases in stream discharge (25%) could generate savings of €40,000 per year.
Benthic diatoms and water chemistry were sampled from 49 stream sites in the Mid-Atlantic Highlands region of the United States to evaluate the use of diatoms as indicators of environmental conditions in streams across varying geographic and ecoregional areas. Diatom samples were collected from depositional and erosional habitats in a randomly selected reach in each stream site. Patterns of diatom species distributions in relation to environmental variables were determined using canonical correspondence analysis. Diatom species in both habitats were highly correlated with a pH gradient. A second gradient was correlated with variables that were commonly associated with agricultural runoff such as turbidity and total phosphorus. The relationship between diatoms and major environmental variables was quantified with regression and calibration models. The correlation between diatom-inferred and observed pH was high (r(2) = 0.90). Cross-validation with jackknifing showed that pH models were reasonably robust (r(2) = 0.69 for depositional habitats, r(2) = 0.67 for erosional habitats). The regression and calibration models for the depositional habitats had only slightly higher predictive powers than those of erosional habitats. The relationship between diatoms and important environmental variables was robust and quantifiable, and the sensitivity of diatom assemblages to environmental conditions did not differ between erosional and depositional habitats. Therefore we concluded that diatoms can be used as quantitative indicators of environmental conditions in lotic systems.
Diatom and water samples were collected from 145 river sampling stations in Finland. The relationship between benthic diatom taxa and measured environmental variables was explored using canonical correspondence analysis (CCA). A weighted averaging (WA) regression model was developed to infer phosphorus concentrations of river water. The optima and tolerances of the diatom species were obtained from the WA regression. The performance of the WA model was assessed using correlation coefficients and the root mean squared error of prediction (RMSEP) between the observed and inferred phosphorus concentrations. The model was cross-validated using an independent test set. The predictive power of the WA model was good (r = 0.91; RMSEP 13.9 μg P/l) in the training set. The weighted averaging also performed well in the independent test set (r = 0.87; RMSEP 15.6 μg P/l). The correlations were only slightly lower and predictive errors larger than in the training set. The weighted averaging gives a tool to evaluate trophic conditions in different ecoregions with the species optima list suitable for prevailing conditions and water quality.
In many countries, the degree of sewage water purification is steadily increasing at present. Consequently, the pollution of running waters by organic oxygen consuming substances is decreasing significantly, too. But neither the classical saprobiological system nor more recently developed pollution indices based on chemical data as well as on diatom communities of the stream benthon reflect the loading (pollution) with inorganic nutrients from diverged purified sewage waters. Therefore, there is additionally a great need for an indication of the trophic status of streams and rivers. Photolithoautotrophic organisms react more or less directly upon nutrient content and nutrient supplies, respectively, and should be taken into account as bioindicators of trophy. Consequently, the universally distributed benthic diatoms of streams and rivers are used as trophic bioindicators. Because there exists a useful approach of diatom indications towards pollution, we improved this method in two ways. (1) The pollution differentiating diatom species have been devided into five instead of three groups. (2) Two new groups of nutrient differentiating or indicating diatoms are introduced: oligo- and eutraphent species. Based on the relative frequencies of these seven groups, we propose a scheme, which classifies from unpolluted, nutrient poor sites (trophic state I) to heavily polluted sites (pollution state 3). The application of this proposal as well as its advantages towards traditional classifications are demonstrated with studies of River Amper, which starts as outflow of Lake Ammersee, Upper Bavaria, Fed. Rep. of Germany.
Many methods for using diatoms for routine monitoring of water quality have been developed in Europe and, in some countries,
these are being used to enforce environmental legislation. In order to facilitate their wider use, particularly with respect
to European Union legislation, steps are being taken to harmonize methodology. In this paper, the principles and practice
of sampling are described in relation to the main habitat types encountered in Europe. Although details of methods and sampling
programmes have to be tailored to particular circumstances and the overall objectives of the monitoring, a number of generalizations
can be made. Where available, rocks and other hard surfaces are the preferred substrates and methods for sampling these are
described. If such substrata are not available, then introduced ('artificial') substrata have many applications. Various types
of introduced substrata can be used successfully, so long as some basic precautions are described. Other types of substrata
such as macrophytes and macroalgae may also be useful under certain circumstances, although there is less consensus in the
literature on the most appropriate methods, and of the validity of comparisons between indices computed from epiphytic and
epilithic communities. When designing surveys, it is recommended that as far as possible, extremes of non-water quality factors
(e.g. shade, current speed, etc) are avoided, unless these are characteristic of the system under investigation. Detailed
guidelines for sampling epilithon are described. Along with the recommendations for sampling other substrata, it is hoped
that these provide a framework that can be adapted to most river types in Europe.
Canonical correspondence analysis (CCA) is a multivariate method to elucidate the relationships between biological assemblages of species and their environment. The method is designed to extract synthetic environmental gradients from ecological data-sets. The gradients are the basis for succinctly describing and visualizing the differential habitat preferences (niches) of taxavia an ordination diagram. Linear multivariate methods for relating two set of variables, such as two-block Partial Least Squares (PLS2), canonical correlation analysis and redundancy analysis, are less suited for this purpose because habitat preferences are often unimodal functions of habitat variables. After pointing out the key assumptions underlying CCA, the paper focuses on the interpretation of CCA ordination diagrams. Subsequently, some advanced uses, such as ranking environmental variables in importance and the statistical testing of effects are illustrated on a typical macroinvertebrate data-set. The paper closes with comparisons with correspondence analysis, discriminant analysis, PLS2 and co-inertia analysis. In an appendix a new method, named CCA-PLS, is proposed that combines the strong features of CCA and PLS2.
The applicability of some diatom methods to quality assessment of differenttypes of Finnish rivers was compared using dominant taxa of diatomcommunities and nutrient level estimations using Trophic Diatom Index(TDI) and a new Phosphorus Diatom Equation (PDE) [Tot. Pcalc (g l-1) = 39 – 0.278 ol-% – 0.117 olme-% – 0.346me-% – 0.006 meeu-% + 1.193 eu-%; n = 97; r2 = 0.742;SE = 17.4]. The overall quality estimations were done by Index ofPollution Sensitivity (IPS) and by Generic Diatom Index (GDI); limit valuesfor quality classes are proposed.
Software for calculation of 6 diatom indices and diversity indices has been created for both Macintosh and IBM compatible computers. This software runs with the data base Omnis 5 under Windows 3.0. It includes three taxonomic files: families, genera and species, and an inventories file. Four types of data inputs are possible. It is always possible to operate simulations and to carry out investigations with simple or combined characters. All files and results of investigations can be listed in different ways. This data base is compatible with both word processing and spreadsheet systems.
This first comprehensive checklist of the diatoms from fresh and weakly brackish water in The Netherlands comprises 948 taxa,
belonging to 776 species in 56 genera. The generaNavicula, which has a very wide ecological amplitude, andNitzschia, which has many pollution tolerant species, are most numerous. Each taxon is identified with a unique eight-letter code,
to facilitate computer processing of data. Ecological indicator values for pH, salinity, nitrogen uptake metabolism, oxygen,
saprobity, trophic state and moisture are presented.
The performance of six diatom indices to evaluate water quality has been studied in the Artois-Picardie water basin. Results show that all of them satisfactorily assess organic pollution which is the main phenomenon responsible for the degradation of water quality throughout the year. However, only the Specific Pollution Sensitivity Index (SPI), the Generic Diatom Index (GDI) and the Commission of Economical Community Index (CEC) show significant correlations with the ionic strength (expressed by chlorides, sulphates and conductivity) and eutrophication (expressed by chlorophyll and nitrates). Diatom indices do not integrate chemical parameters in the same way. Best correlations are obtained through simultaneous or average chemical analyses whereas for other parameters, best correlations are noted with chemical analyses carried out just before diatom sampling. Tests performed on different chemical data sets show that it is possible to make a realistic estimation of water quality during the summer in the Artois-Picardie water basin by using SPI in September.
Patterns of diatom species distribution in relation to total N (TN), total P (TP), and other environmental variables from riffle sites on 2 streams in southern Ontario, Canada, were determined using canonical correspondence analysis (CCA). Relationships with TN and TP were sufficiently strong to develop weighted-averaging (WA) regression-calibration models for inferring stream water concentrations of these nutrients. The models were accurate within ±2.4 μg/L for TP (apparent r2 = 0.52) and ±2 mg/L for TN (apparent r2 = 0.53). An evaluation of the goodness of fit of these models with and without bootstrapping indicated that they performed better (bootstrapped r2 = 0.44 for TP and bootstrapped r2 = 0.42 for TN) than published TN and TP inference models for which similar assessments were made. Based on Organisation for Economic Cooperation and Development eutrophication ratings, the TP model predicted 76% of the mesotrophic and 57% of the eutrophic samples correctly. The model correctly predicted only 20% and 33%, respectively, of oligotrophic and hypereutrophic samples. WA inference models were improved when seasonal variation was removed by using mean summer water quality and diatom data (apparent r2 = 0.76 and bootstrapped r2 = 0.61 for TP; apparent r2 = 0.82 and bootstrapped r2 = 0.70 for TN). Overall, we conclude that epilithic diatoms can be related to TN and TP using these methods, and that WA inference models have utility for indicating eutrophication in southern Ontario lowland streams.
Periphytic communities were investigated using glass slide substrates at four sites downstream from the montane Hyalite Reservoir, Montana, USA. Comparison of the most upstream site with the three lower sites revealed that the discharges to Hyalite Creek stimulated periphytic productivity, increased periphytic proportions of chlorophyll @? in the organic accumulations, and increased diatom species diversity and evenness. As nitrogen concentration was the only stream physiochemical parameter which correlated with periphytic variations, it is probable that ammonia nitrogen discharged from the reservoir was the primary factor influencing periphytic growth. Cocconeis placentula var. lineata dominated generally @?70-80% of the diatom communities at the three downstream sites whereas only three individuals of this species were observed at the upper site. Data from two successional series following colonization of the slides suggested that species other than Cocconies had higher initial growth rates. It appears the Cocconies become dominant at the three downstream sites because of higher efficiencies for obtaining or incorporating limiting nitrogen resources: species other than Cocconeis dominated the diatom communities in which nitrogen concentrations were enriched,apparently because of higher potential growth rates which could be realized with the elevated nutrient conditions. A brief review of the literature and new data presented indicate that species diversity first increases and then decreases as a function of resource abundance.
Macroscopic red algae were sampled simultaneously with diatom sampling from 60 locations in central Finnish rivers and at some rivers in south coast rivers in the summers 1986, 1993 and 1994. In those samples 17 red algal taxa from 5 genera (Audouinella (3). Batrachospermum (7). Lemanea (4), Sirodotia (2) and Tuomeya (1)) were identified. Some of these taxa were new to Finland and two were new for Europe.
The performance of the trophic diatom index (TDI), a new index of trophic status in rivers, was evaluated at sites above and below major sewage works where nutrient removal is being considered. Some modifications to the index are proposed as a result. These include changing the scale from 1 (low nutrients) to 5 (high nutrients) to 0–100, the removal of taxa that are predominately planktonic from the index, and some minor adjustments to taxa sensitivities and indicator values. More detailed guidelines on the choice of sample site are also proposed. In particular, it is important that sites in the “recovery zone” downstream of sewage works are chosen so that the influence of the gross effects of organic pollution on the index is minimised. A “look-up” chart to aid data interpretation is also described. The revised TDI is now recommended to regulatory organisations as a tool for assessing eutrophication in rivers. © 1998 Elsevier Science Ltd. All rights reserved
New legislation has encouraged regulatory biologists in the UK to examine the impacts of eutrophication in rivers for the first time. The principal tools for this have been new indices based on macrophyte and diatom communities. The use of such indices is placed within an appropriate theoretical framework. The importance of recognizing the upper limit of sensitivity of such indices, as well as factors such as organic pollution, which can confuse interpretation, is discussed. Despite their limitations, community-based indices are valuable tools for reconnaissance studies and, in the long-term, as indicators of the extent to which nutrient reductions have led to an ecological response. Some general guidelines for monitoring eutrophication in rivers are proposed.
A study on biological assessment of water pollution using diatom community structure and species distribution was carried out in the Linggi River Basin, Malaysia which was polluted by various urban, industrial and agricultural wastes. A total of 86 diatom taxa belonging to 21 genera were recorded from all eight sampling stations located in the basin, of which 70 species were found on artificial substrates; the remaining 16 species were recorded exclusively on natural substrates. The number of diatom species observed between the stations varied from 22-47 species. The dominant diatom species in decreasing order of abundance were Eunotia vanheurckii, Nitzschia palea, Achnanthes saxonica, Gomphonema parvulum and Achnanthes minutissima. The most common clean water species were Achnanthes minutissima, A. linearis and Synedra rumpens. The most tolerant species were Nitzschia palea followed by Gomphonema parvulum and Pinnularia braunii. Eunotia vanheurckii and Navicula cryptocephala occurred in high densities at both unpolluted and polluted stations and can be considered as the common facultative or indifferent species. Although a large number of species were recorded at the unpolluted stations, equivalent number of species were also found at the moderately polluted stations. However, the number of species was reduced at grossly polluted stations. Nevertheless, a marked variation in species association exists between the unpolluted and polluted stations, but not among the polluted stations to distinguish the type and degree of pollution.
1. The relationship between epilithic algal communities and 17 environmental variables from 17 oligo- to eutrophic lakes in the English Lake District was explored using canonical correspondence analysis (CCA). Total phosphorus (TP) and calcium (Ca) concentration were the most important variables accounting for species distribution.
2. Weighted-averaging regression and calibration models with tolerance downweighting and classical deshrinking were developed to infer TP, Ca, dissolved inorganic carbon (DIC) and conductivity from the relative abundance of 138 epilithic algal taxa.
3. The ranges of the environmental variables covered by the models are 0.8-49.2 μg L−1 for TP, 2.2–13.0 mg L−1 for Ca, 0.5–8.6 mg L−1 for DIC and 38–124 μS cm−1 for conductivity. Within these limits the models can be used to infer chemical properties of lakes from epilithic communities in the English Lake District.
4. The major advantages of using transfer functions based on epilithic communities are the low logistic requirements and the integrative character of algal samples compared to direct point measurements of chemical parameters of the lakes.
Benthic diatom assemblages have been used to evaluate the water quality of two rivers subjected to marked human influences. These rivers, the Llobregat and the Ter, are located in N.E. Spain, and supply water for industrial, agricultural and urban requirements of roughly three million people. The diatom communities in the headwaters are similar in both rivers (Achnanthes minutissima, Cymbella ventricosa, Gomphonema anguslatum). Species of Navicula, Nitzschia and Gomphonema develop in the middle reaches of both rivers when not disrupted by extraneous factors. In the river Ter significant pollution modifies this community and Nitzschia palea, Nitzschia gandersheimiensis and Gomphonema parvulum appear as the most tolerant species. In the Llobregat, the pollution from the salt mine operations also modifies the diatom assemblage and Nitzschia frustulum, Surirella ovata, Navicula atomus are the most abundant species. Reservoirs in the river Ter improve the quality of water and a community of Fragilaria sp. pl. becomes dominant downstream.
1. The relationship between surficial sediment diatom taxa (Bacillariophyceae) and measured limnological variables in forty-six British Columbia lakes was explored using canonical correspondence analysis (CCA). Lake-water total phosphorus concentration (TP), maximum lake depth, conductivity, and calcium concentration each accounted for independent and statistically significant directions of variation in the distribution of diatom taxa.
2. Weighted-averaging (WA) models were developed to infer lake-water TP from the relative abundances of 131 diatom taxa in the surficial sediments of thirty-seven lakes. WA regression and calibration with classical deshrinking provided the best model for TP reconstructions.
3. Our quantitative inference model has two major advantages over existing multiple linear-regression models: (i) inferences are based on the responses of individual taxa to TP, and do not involve grouping the taxa into a small number of ecological categories; and (ii) the model assumes that diatoms respond to TP in a unimodal, rather than a linear, fashion.
4. The WA model can now be used to infer past lake-water TP, within the range 5–28νgr1−1, from diatoms preserved in the sediments of British Columbia lakes. The model can provide quantitative estimates of the onset, rate, and magnitude of lake eutrophication in response to natural processes and human disturbances.
Biological and chemical data were processed to estimate trophic stage and degree of pollution in several streams and rivers
in southern Poland. The majority were eutrophic and some of them heavily polluted; only a few were oligo-mesotrophic. The
differences in the water quality of the rivers were reflected by different types of diatom community and also by the values
for some diatom indices, which were calculated using the latest version of the 'Omnidia' database software. Except for the
Sládeček's index, all diatom indices correlated significantly with organic load (COD), oxygen concentration, conductivity
and most of the measured ions. Some indices showed a significant negative correlation with trophic level (expressed by NH4-N and PO4-P). In general, IPS (Specific Pollution Sensitivity Index) and GDI (Generic Diatom Index) indices gave the best results.
Among the investigated diatom communities, only a few taxa indicated oligo-mesotrophy and oligo-β-mesosaprobity. Most of the
sites were characterised by a greater relative contribution of eutraphent and tolerant ones as well as α-mesosaprobic and
polysaprobic diatoms. This study suggests that the structure of benthic diatom communities and diatom indices, especially
GDI, can be applied for monitoring rivers in Poland.
Use of algae for monitoring rivers III. Agen-ce de l Monitoring organic pollution and eutrophication in the Grand River
- J Prygiel
- B Artois-Picardie
- Douai
- E Rott
- H C Duthie
- E Pipp
PRYGIEL, J., B. A. WHITTON and J. BUKOWSKA (eds.), 1999: Use of algae for monitoring rivers III. Agen-ce de l'Eau Artois-Picardie, Douai. ROTT, E., H. C. DUTHIE and E. PIPP, 1998: Monitoring organic pollution and eutrophication in the Grand River, Ontario, by means of diatoms. – Can.
EC of the European Parliament and of the Coun-cil of 23 October 2000 establishing a framework for Community action in the field of water policy, 72 pp. ELORANTA, P., 1995: Type and quality of river waters in central Finland described using diatom indi-ces
- Corse
- Pierre
Corse, Pierre-Bénite, 218 pp. EC Parliament and Council, 2000: Directive 2000/60/EC of the European Parliament and of the Coun-cil of 23 October 2000 establishing a framework for Community action in the field of water policy, 72 pp. ELORANTA, P., 1995: Type and quality of river waters in central Finland described using diatom indi-ces. pp. 271–280.
Use of algae for monitoring rivers Institut für Botanik Use of algae for monitoring rivers II
- B A Whitton
- E Rott
- G Friedrich
- Innsbruck
- J G Winter
- H C Duthie
WHITTON, B. A., E. ROTT and G. FRIEDRICH (eds), 1991: Use of algae for monitoring rivers. Institut für Botanik, Universität Innsbruck, Innsbruck. WHITTON, B. A. and E. ROTT (eds), 1996: Use of algae for monitoring rivers II. Institut für Botanik, Universität Innsbruck, Innsbruck. WINTER, J. G. and H. C. DUTHIE, 2000: Epilithic diatoms as indicators of stream total N and total P con-centration. – J.
Type and quality of river waters in central Finland described using diatom indices
ELORANTA, P., 1995: Type and quality of river waters in central Finland described using diatom indices. pp. 271–280. – In: MARINO, D. and M. MONTRESOR (eds), Proceedings of the 13th International
Diatom Symposium, 1994. – Biopress, Bristol.
Etude des méthodes biologiques quantitatives d'appréciation de la qualité des eaux
CEMAGREF, 1982: Etude des méthodes biologiques quantitatives d'appréciation de la qualité des eaux.
Rapport Division Qualité des Eaux Lyon – Agence financière de Bassin Rhône – Méditerranée –
Corse, Pierre-Bénite, 218 pp.
Biological indication of trophy and pollution of running waters. – Z. Wasser-Abwasser Forsch
- S Schiefele
STEINBERG, C. and S. SCHIEFELE, 1988: Biological indication of trophy and pollution of running waters.
– Z. Wasser-Abwasser Forsch. 21: 227–234.