(25) Request for a binding decision on whether Geisleria Nitschke (Ascomycota: Strigulaceae) and Geissleria Lange-Bert. & Metzeltin (Bacillariophyceae: Naviculaceae) are sufficiently alike to be confused

P. 647Estudio sobre Diatomeas que se parecen mucho y pueden ser confundidasS

Looking back, looking forward: a review of the new literature on diatom teratological forms (2010–2020)

AbstractOver the last years, issues concerning diatom teratological forms and environmental stress have received growing interest within the scientific community. Publications on this topic dated back to 1890 and were summarized in a review published in 2009 by the journalHydrobiologia, accounting for high citation rates (i.e. 117 citations Scopus and 232 citations Google Scholar, October 2020). This wide interest stimulates the authors to further unravel teratological forms significance in the light of the most recent publications (2010–2020). Diatom teratological forms are one of the best individual-level biomarkers since they provide a rapid response to several environmental stressors, including new emerging pollutants. The mechanisms involved in teratological valve likely involve both cytoskeleton and silicon metabolic pathway impairments. However, teratologies do not seem to weaken the reproduction capacity and viability of the affected individuals. We recognized eight types of teratologies as involving different parts of the valve, depending on genus. In order to summarize the information obtained by several years of research, we suggest a four-step procedure aimed at providing a theoretical pathway that researchers should follow to better explain results obtained in next-future studies and representing a starting point for the development of an environmental index based on teratological forms

Fragilaria odeloucaensis sp. nov. (Bacillariophyta, Fragilariaceae) a diatom from temporary streams in southern Portugal

A new species of araphid diatom is described from a temporary stream in southern Portugal, Fragilaria odeloucaensis sp. nov., which belongs to the group of Fragilaria with widely linear to lanceolate valve outline, spaced striae, lacking spines, and with well-developed apical pore fields. The new taxon can be distinguished based on five unique features within this group, the lanceolate valves with capitate apices, the zig-zagged axial area, the central area with squared fascia, the apical pore fields clearly sunken into the valve apices and the heterovalvar frustules (with respect to striae distancing). Ecological features of the type locality and an additional sampling point where the new species was found are given, together with a discussion of the taxonomic position of the new species within Fragilaria, and the approach used herein for the identification of diagnostic features. This approach includes a detailed analysis of the internal and external characteristics of the axial areavirgae-striae complex, central area, apical pore fields and differences among valves of the same frustule, in addition to the traditional valve shape and morphometric features.This work was co-funded by the Science and Management of Intermittent Rivers & Ephemeral Streams (SMIRES) COST Action (CA 15113), http://www.smires.eu, the European Union through the European Regional Development Fund, framed within the Operational Programme Competitiveness and Internationalization, COMPETE 2020 through the ICT project (UID /GEO /04683/2013) with reference POCI -01-0145-FEDE R-007690, and the Agência Portuguesa do Ambiente, APA-000004DFIN .AA LP/2017 integrated within the Operational Program for Sustainability and Efficiency in the Use of Resources 2014-20, POSEUR-03-2013-FC-000001. Co-funding was also provided within the framework of the DIATOMS project (LIST - Luxembourg Institute of Science and Technology)

On some common and new cavum-bearing Planothidium (Bacillariophyta) species from freshwater

[EN] Thirteen Planothidium species are illustrated and discussed in a detailed morphological account based on light and scanning electron microscopy analysis of modern and historic materials related to the names Planothidium rostratum (Østrup) Lange–Bertalot and Planothidium frequentissimum (Lange–Bertalot) Lange–Bertalot. Eight species from freshwater environments in Europe, Asia and South America are proposed as new. All taxa here discussed and illustrated belong to the group of species characterized by the presence of a cavum in the rapheless valve. Additional information concerning their distribution and ecology is briefly commented based on a thorough literature revisionSIThis study was realized in the framework of the project DIATOMS of the Luxembourg Institute of Science and Technology (LIST). We gratefully acknowledge Denise C. Bicudo (Instituto de Botânica de São Paulo, Brazil), Friedel Hinz (Friedrich–Hustedt–Zentrum für Diatomeenforschung, Bremerhaven, Germany), Martin Kelly (Bowburn Consultancy, Durham, UK), Rémy Marcel (AQUABIO, Cournon d’Auvergne, France), Marina Potapova (The Academy of Natural Sciences, Diatom Herbarium, Philadelphia, PA, USA), Jeanne Rigaut (GREBE, Groupe de Recherche et d’Etudes Biologie et Environnement, Lyon, France), Francois Straub (PhycoEco, La Chaux–de–Fonds, Switzerland) and Frank Véry (DREAL Auvergne–Rhône–Alpes, France) for providing materials. The Vlaamse MilieuMaatschappij (VMM, Belgium) is also thanked for providing some of the analysed sample

Pseudostaurosira cataractarum comb. nov. (Bacillariophyta): type analysis, ecology and world distribution of a former “centric” diatom

P. 53-63The transfer of Melosira cataractarum Hust. to the genus Pseudostaurosira D.M. Williams & Round is presented based on a detailed analysis of the type material from Java (Malay Archipelago) using light and scanning electron microscopy. The species was initially described as a “centric” diatom within the genus Melosira C. Agardh and was later transferred to the genus Aulacoseira Thwaites. Pseudostaurosira cataractarum (Hust.) C.E. Wetzel, E. Morales & Ector comb. nov. differs from other species of the genus by its smaller size, typical radiate striae arrangement and absence of apical pore fields. We additionally propose the transfer of Fragilaria sopotensis Witkowski & Lange-Bert. to the genus Pseudostaurosira, a species that is morphologically similar to P. cataractarum.S

Response of epilithic diatom communities to environmental gradients in subtropical temperate Brazilian rivers

This work aims to analyse the response of epilithic diatom communities to enviranmental gradients in subtropical temperate southern Brazilian rivers to contribute to the development of a widely applicable methodology for water-quality monitoring. Samples for physical, chemical and biological determination were collected monthly, fram December 2001 to November 2002 and fram March 2003 to February 2004, at 9 stations along the rivers Pardo and Pardinho in the hydrographical basin of Rio Pardo, State of Rio Grande do Sul (RS), Brazil. Physical and chemical variables (water temperature, pH, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, nitrates, nitrites, phosphates and total dissolved solids) and biological variables (epilithic diatom communities) were used as parameters for water-quality assessment. The data matrix was examined by means of a multivariate ordination using Detrended Correspondence Analysis (DCA). In total, 270 taxa were identified to specific or infra-specific levels. The results showed that of all the physical and chemical variables used, the main gradient along the DCA first axis was eutraphication, which was indicated by its significant correlation with phosphates (p < 0.00l). Hence, the species' scores on the DCA axis were used as an operational criterion for indicating their tolerance to eutrophication. From this analysis, the 10 taxa that were the most tolerant to eutrophication were: Cyclotella meneghiniana, Fallacia monoculata, Nitzschia acicularis, N. clausii, N. nana, N. palea, Nitzschia sp., Pinnularia sp., Sellaphora pupula sensu lato and Ulnaria acuso The present study showed that epilithic diatom assemblages reflect anthropogenic changes in hydrographic basins in subtropical temperate streams, especially pollution by organic enrichment and eutraphication. Key words: Diatoms, eutrophication, biomonitoring, southern Brazilian rivers.Este trabajo pretende analizar la respuesta de la comunidad de diatomeas epilíticas a gradientes ambientales en ríos brasileños templados subtropicales, con el objetivo de contribuir al desarrollo de una metodología ampliamente aplicable para la monitorización de la calidad del agua. Diversas muestras para determinaciones físicas, químicas y biológicas fueron recogidas mensualmente, de diciembre de 2001 a noviembre de 2002, y de marzo de 2003 afebrero de 2004, en nueve esta­ciones de muestre o distribuidas a lo largo de los ríos Pardo y Pardinho, localizados en la Cuenca Hidrográfica del Río Pardo, Estado del Río Grande del Sur; Brasil. Variables físicas y químicas (temperatura del agua, pH, oxígeno disuelto, demanda bioquímica de oxígeno, demanda química de oxígeno, nitratos, nitritos, fosfato y sólidos totales disueltos) y biológicas (co­munidad de diatomeas epilíticas) fueron usadas como parámetros para evaluar la calidad del agua. El conjunto de datos fue analizado por medio de una ordenación multivariante usando el Análisis de Correspondencias sin Tendencias (DCA). En total, 270 taxones fueron identificados a nivel especifico o infra-especifico. Los resultados indicaron que, entre todas las variables físicas y químicas usadas, el principal gradiente establecido a lo largo del primer eje DCA fue la eutrojización, señalada por su correlación significativa con la concentración de fosfatos (p < 0.001). De esta forma, los valores alcanzados por las especies en el primer eje DCA fueron usados como un criterio operativo para indicar su tolerancia a la eutrojización. Los 10 taxones más tolerantes a la eutrojizaciónfueron: Cyc10tella meneghiniana, Fallacia monoculata, Nitzschia acicularis, N. c1ausii, N. nana, N. palea, Nitzschia sp., Pinnularia sp., Sellaphora pupula sensu lato y Ulnaria acuso El presente estudio muestra que la comunidad de diatomeas epilíticas refleja cambios antropogénicos en ríos templados subtropicales de cuencas hidrográjicas, especialmente la contaminación por enriquecimiento orgánico y eutrofización

Epilithic diatom assemblages and environmental quality of the Su Gologone karst spring (centraleastern Sardinia, Italy)

Karst springs are considered among the most vulnerable groundwater-dependent ecosystems. Despite their ecological value and importance as strategic water sources, Mediterranean karst springs are still poorly investigated. The aim of this study was to analyse the epilithic diatom assemblages and to test their usefulness as indicators of environmental quality on the Su Gologone spring (central-eastern Sardinia, Italy), a biotope of great natural value and a precious source of drinking water. A total of 89 diatom taxa were found with 25 new records for Sardinian running waters. Species richness, Shannon-Wiener and Pielou indices showed good biotic integrity. The dominant taxa were alkaliphilous, halophobous-oligohalobous exigent, xeno-oligosaprobic and characteristic of oligotrophic waters. The eutrophication/pollution index − diatom based (EPI-D) and the Navicula Nitzschia Surirella indices indicated respectively an excellent/good biological water quality and a low physical disturbance. However, the biological and chemical oxygen demand, and the microbiological variables (E. coli, fecal and total coliforms) revealed an organic contamination of the water, although moderate. The judgment provided by the EPI-D should be verified after updating of the index. In fact, 10 taxa found in this study are not currently considered by the EPI-D method

Response of epilithic diatom communities to environmental gradients in subtropical temperate Brazilian rivers

P. 323-340This work aims to analyse the response of epilithic diatom communities to environmental gradients in subtropical temperate southern Brazilian rivers to contribute to the development of a widely applicable methodology for water-quality monitoring. Samples for physical, chemical and biological determination were collected monthly, from December 2001 to November 2002 and from March 2003 to February 2004, at 9 stations along the rivers Pardo and Pardinho in the hydrographical basin of Rio Pardo, State of Rio Grande do Sul (RS), Brazil. Physical and chemical variables (water temperature, pH, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, nitrates, nitrites, phosphates and total dissolved solids) and biological variables (epilithic diatom communities) were used as parameters for water-quality assessment. The data matrix was examined by means of a multivariate ordination using Detrended Correspondence Analysis (DCA). In total, 270 taxa were identied to specic or infra-specic levels. The results showed that of all the physical and chemical variables used, the main gradient along the DCA rst axis was eutrophication, which was indicated by its signicant correlation with phosphates ( p < 0.001). Hence, the species’ scores on the DCA axis were used as an operational criterion for indicating their tolerance to eutrophication. From this analysis, the 10 taxa that were the most tolerant to eutrophication were: Cyclotella meneghiniana, Fallacia monoculata, Nitzschia acicularis, N. clausii, N. nana, N. palea, Nitzschia sp., Pinnularia sp., Sellaphora pupula sensu lato and Ulnaria acus. The present study showed that epilithic diatom assemblages reect anthropogenic changes in hydrographic basins in subtropical temperate streams, especially pollution by organic enrichment and eutrophicationS

Chamaepinnularia thermophila (Bacillariophyceae) : synonymy with Navicula tongatensis Hustedt and update of its geographic distribution and ecology

Abstract Chamaepinnularia thermophila is a small and poorly known diatom species. After the first description from a hot spring in Guadalupe in 1952, its presence appeared to be limited to a few other springs of the French Antilles. The objective of this study is to report new information on aspects of taxonomy, distribution and ecology of this species. Accurate analysis under light and scanning electron microscope of the material collected on different substrates (cobbles, macrophytes and fine sediments) from a thermo-mineral spring of Sardinia (Italy) allowed us to document the first record of the species in the Mediterranean area. Furthermore, the comparison with Navicula tongatensis from Hustedt's original material, carried out because of their similarity, revealed identical morphological characteristics suggesting their consequent synonymy. Based on the information available in the literature and our data, C. thermophila is a rare species present mainly in tropical areas, in thermal springs with alkaline pH, medium to high conductivity and low to moderate nutrient content. The occurrence of the species at sites with very different environmental characteristics seems unusual, but it could indicate a broader ecological range. This study contributes to the standardization of the nomenclature used for this species so far and provides the first framework on its global geographic distribution and ecology