Periphytic Diatoms Research Articles

Use of diatom assemblages as biomonitor of the impact of treated uranium mining effluent discharge on a stream: case study of the Ritord watershed (Center-West France)

The rehabilitation of French former uranium mining sites has not prevented the contamination of the surrounding aquatic ecosystems with metal elements. This study assesses the impact of the discharge of treated uranium mining effluents on periphytic diatom communities to evaluate their potential of bioindication. A 7-month survey was conducted on the Ritord watercourse to measure the environmental conditions of microalgae, the non-taxonomic attributes of periphyton (photosynthesis and biomass) and to determine the specific composition of diatom assemblages grown on artificial substrates. The environmental conditions were altered by the mine waters, that contaminate the watercourse with uranium and with chemicals used in the pit-water treatment plants (BaCl2 and Al2(SO4)3). The biomass and photosynthetic activity of periphyton seemed not to respond to the stress induced by the treated mining effluents whereas the altered environmental conditions clearly impacted the composition of diatom communities. Downstream the discharges, the communities tended to be characterized by indicator species belonging to the genera Fragilaria, Eunotia and Brachysira and were highly similar to assemblages at acid mine drainage sites. The species Eunotia pectinalis var. undulata, Psammothidium rechtensis, Gomphonema lagenula and Pinnularia major were found to be sensitive to uranium effluents whereas Neidium alpinum and several species of Gomphonema tolerated this contamination. The relevance of diatoms as ecological indicator was illustrated through the changes in structure of communities induced by the discharge of uranium mining effluents and creates prospects for development of a bioindicator tool for this kind of impairment of water quality.

Cavinula lilandae (Bacillariophyta), a new diatom species from the Congo Basin, Central Africa

Cavinula lilandae, a small new diatom from the Congo Basin in Central Africa, was observed in acid riverine habitats in an almost pristine tropical rain forest. It occurred in a periphytic diatom community dominated by Eunotia spp. and Fragilariforma strangulata (Zanon) Williams & Round. Beside the type locality in the Baomba Stream, and the closely located Lilanda River, in the Democratic Republic of Congo, this taxon was also observed in a small river in Zambia, north of the Bangweulu swamps. Cavinula lilandae is distinguished from other taxa within the genus Cavinula D.G. Mann & A.J. Stickle by the following characteristics: uniseriate striae becoming irregularly biseriate near the poles; irregularly formed areolae; and irregular depressions in the valve face close to the axial area which are not perforating the valve face.

Coherence of phytoplankton and attached diatom-based ecological status assessment in Lake Balaton

Coherence between ecological status assessment by phytoplankton and attached diatoms was analyzed in the littoral zone of Lake Balaton. Sampling of periphytic diatoms, phytoplankton, and water were carried out at ten different littoral sites in the northern and southern shores of the lake for a year. Phytoplankton species were sorted into functional groups and ecological status was assessed by means of the phytoplankton assemblage Q index. The index TDIL was calculated using quantitative attached diatom data. Significant differences were found between the ecological assessments based on phytoplankton and phytobenthos metrics, both seasonally and spatially. The Q index indicated ecological states varying from bad to good, while the average of diatom indices varied from moderate to high conditions. The Q index provided more realistic ecological status of Lake Balaton, compared with trophic status based on TP values, especially in the summer period. Differences in the response-time indication of phytoplankton and attached diatoms suggest that lack of coherence should also be expected between the responses of other BQEs.

Biological responses to permafrost thaw slumping in Canadian Arctic lakes

Summary1. Rapid environmental change occurring in high‐latitude regions has the potential to cause extensive thawing of permafrost. Retrogressive thaw slumps are a particularly spectacular form of permafrost degradation that can significantly impact lake–water chemistry; however, to date, the effects on aquatic biota have received little attention.2. We used a diatom‐based palaeolimnological approach featuring a paired lake study design to examine the impact of thaw slumping on freshwater ecosystems in the low Arctic of western Canada. We compared biological responses in six lakes affected by permafrost degradation with six undisturbed, reference lakes.3. Slump‐affected lakes exhibited greater biological change than the paired reference systems, although all systems have undergone ecologically significant changes over the last 200 years. Four of the six reference systems showed an increase in the relative abundance of planktonic algal taxa (diatoms and scaled chrysophytes), the earliest beginning about 1900, consistent with increased temperature trends in this region.4. The response of sedimentary diatoms to thaw slumping was understandably variable, but primarily related to the intensity of disturbance and associated changes in aquatic habitat. Five of the slump‐affected lakes recorded increases in the abundance and diversity of periphytic diatoms at the presumed time of slump initiation, consistent with increased water clarity and subsequent development of aquatic macrophyte communities. Slump‐affected lakes generally displayed lower nutrient levels; however, in one system, thaw slumping, induced by an intense fire at the site in 1968, ostensibly led to pronounced nutrient enrichment that persists today.5. Our results demonstrate that retrogressive thaw slumping represents an important stressor to the biological communities of lakes in the western Canadian Arctic and can result in a number of limnological changes. We also show that palaeolimnological methods are effective for inferring the timing and response of aquatic ecosystems to permafrost degradation. These findings provide the first long‐term perspective on the biological response to permafrost thaw, a stressor that will become increasingly important as northern landscapes respond to climate change.

Assessing the condition of the Missouri, Ohio, and Upper Mississippi rivers (USA) using diatom-based indicators

Diatom-based indicators were developed to assess environmental conditions in the Missouri, Ohio, and Upper Mississippi rivers. Disturbance gradients, comprising the first two principal components derived from a suite of stressor variables, included a trophic gradient (Trophic) and a gradient reflecting agriculture and other development activities (Ag/Dev). Diatom-based indicators were developed by creating models using weighted average calibration and regression-based transfer functions to relate planktonic and periphytic diatom species assemblages to each disturbance gradient. The most predictive disturbance models combined phytoplankton and periphyton assemblages into a single bioindicator model (observed versus inferred: Trophic \( r_{\text{boot}}^{2} = 0. 5 6 \); Ag/Dev \( r_{\text{boot}}^{2} = 0. 7 0 \)). The geographic applicability of bioindicators was assessed by limiting sample geographical range during model calibrations. Geographic scale was limited by creating bioindicators using samples from: (a) each river, and (b) combined Mississippi/Missouri samples excluding Ohio River sites which were chemically unique. Indicator performance decreased with geographically restrictive models, therefore river basin-wide models, developed across all three rivers, is recommended. The most effective diatom-based disturbance bioindicators for this great river ecosystem could be applied using phytoplankton, periphyton, or combined assemblages to infer both trophic and agriculture/development disturbances.

Linking spatial distributions of sediment diatom assemblages with hydrological depth profiles in a plateau deep-water lake system of subtropical China.

The spatial distributions of approximately 160 diatom taxa from surface sediments of the plateau deep-water Lugu Lake were investigated. The results exhibited a change in the sediment diatom composition with increasing water depth. The main patterns of variation, derived from a principal component analysis (PCA) and detrended correspondence analysis (DCA), showed that diatom community composition was divided into three depth gradients (near-shore zone; mid-depth zone; profundal deep zone). With increasing depth, the pattern of predominantly periphytic taxa in the shallow waters changed to planktonic assemblages dominated by Cyclotella ocellata, Asterionella formosa and Cyclostephanos dubius. Diatom species diversity decreased from the shallow near-shore zone to the deeper open waters. In addition, there was an increase in the ratio of planktonic to periphytic diatoms at depths >30 m. These distinct spatial patterns in diatom distribution are clear markers of current water levels within Lake Lugu and represent a benchmark for evaluating paleolimnological changes in water levels, which can be an indirect proxy of regional climate in this monsoon region of southern Asia.

Seasonal variations of periphytic diatom community in artificial substrata in Huizhou section of the Dongjiang River, Guangdong Province, Southern China

Although diatom has been widely used in biological or ecological monitoring of rivers,there is little information on diatom communities in most of Chinese rivers.In this study,we reported periphytic diatoms on artificial substrata(tile)in the Huizhou section of the Dongjiang River.We analyzed seasonal variations of the species composition and the relationship between the relative abundance and seasonal environmental factors at five sampling stations in 2010.A total of 153 periphytic diatom species,belonging to 40 genera,were identified.Dominant genera included Achnanthidium,Gomphonema,Melosira,Navicula,Nitzschia and Synedra.Gomphonema parvulum and Nitzschia palea were the common species in all the sampling sites with relative abundance1%.However,the relative abundance of the two species varied largely in seasons.Chl.a concentrations of the periphytic algae were positively correlated with the temperature.Redundancy analysis showed that water temperature,DO,NH+4-N,PO3-4-P,conductivity and pH were the major factors influencing the community structure of periphytic diatoms.Furthermore,hydrographic condition was crucial to some mobile species such as Nitzschia palea,whose relative abundance was low in summer mainly due to flushing in flood season.

Periphytic diatom communities in the littoral zone of the urban lake Jeziorak Mały (Masurian lake district, Poland).

This study on plant periphyton (epilython, epiphyton, and periphyton communities on artificial substratum – separator pipes) was carried out in the littoral zone of lake Jeziorak Maly in 2002 and 2003. In addition to floristic analysis, changes in the abundance and biomass of periphytic diatoms with respect to physio-chemical water parameters in the season between April and October were analyzed. The highest number of periphytic diatoms was found in the pipes in June, and the highest biomass of epilython was established in September, in conditions of high contents of Ca and Si biogenes. Moreover, the indicator potential of diatoms was used to determine the trophy and saproby of the lakes waters. The largest participation of eutraphents in the biomass in all the diatom communities generally indicates the eutrophic character of the lakes waters, the dominance of meso-saprobes and amoderate content of organic matter. Moreover, alarge proportion of alpha-mesosaprobes (dominant Navicula gregaria) in the biomass of periphytic diatoms in the pipes indicates the highest degree of contamination by organic matter there in comparison to other substrates, while the epilython had the highest biomass of beta-alpha-meso-saprobes (dominant Diatoma vulgaris), an average degree of contamination with adominance of beta-meso-saprobes (subdominant Cocconeis placentula) and the least degree of contamination by organic matter.

Developing biomonitoring protocols for shallow Arctic lakes using diatoms and artificial substrate samplers

Growing concerns over effects of climate warming and other stressors on shallow Arctic lakes and ponds stimulate the need to develop and implement effective protocols to track changes in ecological integrity. This study assesses seasonal and spatial variability of periphytic diatom communities in a shallow Arctic lake in northern Yukon Territory to establish biomonitoring protocols. Artificial substrate samplers, which mimic macrophytes, allow direct measurement of biotic responses to shifting environmental conditions and control for possible confounding factors (e.g., accrual time and microhabitat type). Artificial substrate samplers were deployed at three locations and retrieved at three times (early, mid, and late) during the ice-free season. Analyses identified that diatom abundance increased exponentially and community composition changed significantly over the ice-free season, despite little variability in water chemistry, but did not differ among the three sampling locations within the lake. Patterns of seasonal succession in diatom community composition were characterized by first arrival of well-dispersed taxa, which included several planktonic taxa, followed by a transitional phase composed of planktonic and periphytic taxa, and culminated with dominance by periphytic species, mainly Achnanthes minutissima (Kutzing). Results highlight the role of seasonal succession on artificial substrate colonization and the need to deploy artificial substrate samplers for the duration of the ice-free season to capture peak periphytic algal abundance. Low spatial variability of shallow Arctic lakes allows for samplers to be deployed at one single location to characterize diatom community composition.

Responses and structural recovery of periphytic diatom communities after short-term disturbance in some rivers (Hanoi, Vietnam)

Field transfer experiments of periphytic diatom assemblages developed on artificial substrates were set up to assess the responses of those communities to environmental disturbances. The glass slides were positioned for colonization at the relatively unpolluted site (Red, in the Red River) and at the heavily polluted site (TL, in the To Lich River) in the beginning of the experiment. After a period of 2 weeks, the colonized glass slides were concomitantly transferred from the unpolluted Red site to the heavily polluted TL site and to the moderate polluted site (NT2, in the Nhue River) and, conversely, from the TL site to the Red site, and then to the NT2 site. The responses and the adapting capacity of periphytic diatom communities to environmental changes were assessed through the cell density, diversity index, species richness, taxonomic composition, and diatom indices after 2 and 4 weeks of transfer periods. For all transfers except for the transfer from the Red to the TL site in which the growth inhibition of diatom cells was found, the diatom density significantly increased until the end of the experiment. Thus, the diatom communities have expressed their pollution tolerance or sensitivities by changing their composition to adapt themselves to environmental changes. Characteristic species of the Red site (Gyrosigma scalproides, Navicula recens) were replaced by Nitzschia palea, Nitzschia umbonata, Aulacoseira granulate typical species of the NT2 site, in the biofilm transferred from the Red site to the NT2 site. The relative abundances of typical diatom species of the Red site proliferated in the biofilm transferred from the TL site to the Red site. The replacement of periphytic diatom communities appeared after the transfer from the second week at the different sites. The slow shift of the species towards the typical species at the TL site could result from the organized structure of diatoms within biofilm before the transfer from the Red site to the TL site. The shifts in values of the Index of Specific Polluosensitivity and Diatom Assemblage Index to organic pollution throughout the experiment indicated the clear sensitivity of these indices to water quality changes.

THE INFLUENCE OF SUBMERGED MACROPHYTES ON SEDIMENTARY DIATOM ASSEMBLAGES(1).

Submerged macrophytes are a central component of lake ecosystems; however, little is known regarding their long-term response to environmental change. We have examined the potential of diatoms as indicators of past macrophyte biomass. We first sampled periphyton to determine whether habitat was a predictor of diatom assemblage. We then sampled 41 lakes in Quebec, Canada, to evaluate whether whole-lake submerged macrophyte biomass (BiomEpiV) influenced surface sediment diatom assemblages. A multivariate regression tree (MRT) was used to construct a semiquantitative model to reconstruct past macrophyte biomass. We determined that periphytic diatom assemblages on macrophytes were significantly different from those on wood and rocks (ANOSIM R = 0.63, P < 0.01). A redundancy analysis (RDA) of the 41-lake data set identified BiomEpiV as a significant (P < 0.05) variable in structuring sedimentary diatom assemblages. The MRT analysis classified the lakes into three groups. These groups were (A) high-macrophyte, nutrient-limited lakes (BiomEpiV ≥525 μg · L(-1) ; total phosphorus [TP] <35 μg · L(-1) ; 23 lakes); (B) low-macrophyte, nutrient-limited lakes (BiomEpiV <525 μg · L(-1) ; TP <35 μg · L(-1) ; 12 lakes); and (C) eutrophic lakes (TP ≥35 μg · L(-1) ; six lakes). A semiquantitative model correctly predicted the MRT group of the lake 71% of the time (P < 0.001). These results suggest that submerged macrophytes have a significant influence on diatom community structure and that sedimentary diatom assemblages can be used to infer past macrophyte abundance.

Diatomáceas perifíticas em Potamogeton polygonus Cham. &amp; Schltdl.: citações pioneiras para o estado do Paraná

Diatomáceas perifíticas em Potamogeton polygonus Cham. &amp; Schltdl.: citações pioneiras para o Estado do Paraná. Realizou-se o estudo taxonômico das diatomáceas perifíticas associadas à macrófita aquática Potamogeton polygonus. Espécimes da macrófita foram coletados em fevereiro, maio e novembro/2005 e março/2006, em uma lagoa artificial e no rio Salto Amazonas, ambos localizados em fazendas no município de General Carneiro, Paraná. Baseados na análise de lâminas permanentes com material perifítico oxidado registraram-se cento e quarenta e sete táxons, sendo 55 exclusivos do ambiente lêntico, 34 exclusivos do ambiente lótico e 58 observados em ambos locais. As famílias mais representativas foram Eunotiaceae (13,6%), Pinnulariaceae (11,6%) e Naviculaceae (9,6%). Os gêneros com maior número de espécies e variedades foram Eunotia com 20 táxons e Pinnularia com 17. O estudo contribuiu com 18 novas citações para o Estado do Paraná.

Diatomáceas perifíticas abundantes em três córregos com diferentes ações antrópicas em Maringá, PR, Brasil

Realizou-se o estudo taxonomico das diatomaceas perifiticas predominantes em tres corregos, Nazare, Guaiapo e Remo, influenciados por diferentes acoes antropicas. As coletas foram bimestrais, contemplando tres locais dos corregos, cabeceira, meio e foz, no periodo de julho de 2007 a agosto de 2008. Foram registradas 26 especies predominantes entre as 151 diatomaceas determinadas nas amostras. Sete especies foram abundantes ou dominantes nos tres corregos estudados: Eolimna minima (Grunow) Lange-Bertalot (dominante no Corrego Remo), Gomphonema lagenula Kutzing (dominante no Corrego Guaiapo), Gomphonema pumilum (Grunow) Reichardt & Lange-Bertalot e Nupela praecipua (Reichardt) Reichardt (dominantes no Corrego Nazare), Geissleria aikenensis (Patrick) Torgan & Oliveira, Nitzschia palea (Kutzing) Smith e Sellaphora seminulum (Grunow) Mann (abundantes nos tres corregos). Duas especies foram abundantes exclusivamente no Corrego Nazare urbano, 13 no Corrego Remo rural e quatro no Corrego Guaiapo que sofre influencia de ambos ambientes.

Planktonic and periphytic diatoms as indicators of stress on great rivers of the United States: Testing water quality and disturbance models

Planktonic and periphytic diatom assemblages were investigated as potential biological indicators of ecological conditions in the Ohio, Missouri and Upper Mississippi rivers. Diatoms were analyzed to determine which of the two assemblage types was most appropriate for monitoring environmental conditions. The comparative effectiveness of diatom data format was similarly evaluated, testing relative and absolute abundance data. Stressor gradients for the rivers were created using principal components analysis for suites of water quality variables, landscape disturbance variables, and combined variables. Diatom-based weighted averaging transfer functions were developed for these integrated stressor gradients using each habitat and data format. Representing the diatoms as relative abundance data provided optimal tracking of environmental stress, and both periphyton and phytoplankton showed potential as indicators of disturbance. These results reinforce the use of relative abundance data, often used for diatom water quality monitoring, over more labor intensive data formats. Diatom-based models were also created to infer water quality measures and to compare measured and diatom-inferred water quality to landscape stressors. In most instances, diatom-inferred water quality data were more strongly related to watershed-based stressors. This investigation supports the value of diatoms in assessing landscape stressors in large rivers as well as the more traditionally applied water quality conditions. The findings further suggest both planktonic and periphytic diatom assemblages may be used as bioindicators of river condition and may provide unique stressor response information.

Characteristics and colonizing processes of periphytic diatom communities downstream of dam sites along the Katsuuta River, Tokushima Prefecture

Characteristics and colonizing processes of periphytic diatom communities downstream of dam sites along the Katsuuta River, Tokushima Prefecture

Impact of the herbicide metolachlor on river periphytic diatoms: experimental comparison of descriptors at different biological organization levels

Impact of the herbicide metolachlor on river periphytic diatoms: experimental comparison of descriptors at different biological organization levels

Variations of periphytic diatom sensitivity to the herbicide diuron and relation to species distribution in a contamination gradient: implications for biomonitoring

Diatoms are commonly used as bioindicators of trophic and saprobic pollution in rivers. However, more knowledge is needed concerning their sensitivity to toxicants such as agricultural herbicides. In this study, seven species of periphytic diatoms were isolated from the Morcille River (Beaujolais area, France) which presents a streamward contamination gradient by pesticides and particularly diuron. The sensitivity of these species to diuron was assessed through ecotoxicological tests based on short-term growth inhibition of monospecific cultures. After application of an appropriate toxicological model, EC50 were determined and the species were ranked according to their tolerance. EC50 values ranged from 4.5 to 19 μg L(-1). Finally, the results were related to field periphyton samples from an upstream and a downstream site in order to check if variations in specific relative abundance between sites are consistent with differences in tolerance to diuron. Species distribution between sites was only partially in accordance with toxicological results suggesting that other factors (toxic or trophic) have an important influence on diatom communities in the river. Nevertheless, diatoms showed their potential to indicate water contamination by pesticides and toxic indices could be developed in complement to existing trophic indices.

Impact of the herbicide metolachlor on river periphytic diatoms: Experimental comparison of descriptors at different biological organization levels

A microcosm experiment was carried out in order to test the effect of the herbicide metolachlor on river periphytic diatoms and to find potential diatom bioindicators of contamination. Effects were investigated at different biological organization levels (biofilm, diatom community, population and individual levels). The colonization of glass substrates by natural biofilm in artificial streams did not vary quantitatively between control and contaminated conditions (5 and 30 μg.L− 1 ). However, non-parametric multivariate analysis of variance revealed a significant difference between contaminated and control diatom communities with regard to species composition. The difference was due to the greater development of probably tolerant species in the presence of the herbicide (e.g. , Planothidium frequentissimum, Planothidium lanceolatum, Amphora montana, Surirella brebissonii and Nitzschia gracilis ). An increase in the occurrence of abnormal forms was observed in relation to metolachlor concentration. In particular, up to 8% of the frustules of the species Surirella angusta exhibited prominent deformities. Monospecific acute toxicity tests were then performed on two species to estimate toxicity parameters based on growth inhibition. These tests also confirmed the teratogenic effect of the herbicide on S. angusta . This study shows that low concentrations of metolachlor in natural streams may significantly alter diatom community structure and that abnormal diatom forms should be taken into account in water contamination assessment.

Diatomáceas perifíticas em Polygonum hydropiperoides Michaux, reservatório do Passaúna, Região Metropolitana de Curitiba, Paraná, Brasil

A diatomoflórula perifítica aderida a Polygonum hydropiperoides Michaux foi estudada em um plano amostral trimestral, no reservatório do rio Passaúna, estado do Paraná, Brasil. Partes da macrófita foram raspadas para a retirada do perifíton, que foi oxidado para a confecção de lâminas permanentes. Cento e seis táxons foram observados e suas dimensões e ilustrações foram apresentadas. Fragilariaceae foi a família mais representativa, com oito gêneros. Entre os 39 gêneros observados Navicula Bory, Gomphonema Ehrenberg e Nitzschia Hassall apresentaram as maiores riquezas taxonômicas. Quinze novos registros para o estado do Paraná foram descritos.

Diatomáceas perifíticas da represa Itaqui, São José dos Pinhais, Paraná: Fragilariales, Eunotiales, Achnanthales e Gomphonema Ehrenberg

Realizou-se o levantamento florístico das espécies de diatomáceas perifíticas incluídas em Fragilariales, Eunotiales, Achnanthales e Gomphonema Ehrenberg, em uma represa do Rio Itaqui, localizada no município de São José dos Pinhais, PR. Lâminas de vidro foram utilizadas como substrato, as quais permaneceram submersas durante 30 dias no ambiente. Quatro coletas trimestrais, de maio de 2008 a fevereiro de 2009, foram realizadas para análise qualitativa. Amostras foram coletadas para estimar o estado trófico da represa, a qual foi classificada como hipereutrófica. Determinaram-se 49 táxons, sendo 44 em nível infragenérico. Doze novos registros foram adicionados à diatomoflórula paranaense: Fragilaria socia, Eunotia rabenhorstiana var. elongata, E. soleirolii, E. ventricosa var. brevis, Gomphonema parvulum f. saprophilum, G. pumilum, Achnanthes minuscula, Nupela wellneri, Planothidium frequentissimum, Ulnaria sp., Eunotia sp.2 e Gomphonema sp.2. Os táxons determinados em nível genérico, Ulnaria sp., Eunotia sp.1, Eunotia sp.2, Gomphonema sp.1 e Gomphonema sp.2 devem ser alvo de estudos posteriores, pois nenhuma forma semelhante foi registrada na literatura consultada.