Diatom community biodiversity in an Alpine protected area: a study in the Maritime Alps Natural Park

As part of the "All Taxa Biodiversity Inventories" (ATBIs) coordinated by the European Distributed Institute of Taxonomy (EDIT), we analysed diatom communities colonizing different habitats of the Valasco Valley (Maritime Alps Natural Park). The aim of this research was to shed light on the diatom richness in an Alpine context through i) the collection of data concerning diatom communities inhabiting an unexplored watershed of the Maritime Alps Natural Park, including all of the most important aquatic habitats (comparison among river, springs and peat bogs) and assemblages (epilithic and epiphytic diatom communities); ii) analysis of the main environmental factors driving the development of diatom communities in different habitats. We completed a list of 174 diatom taxa. In general, river samples were poorer in terms of species richness than spring and peat bog ones, probably due to the selective role of the fast flow, while springs sheltered the highest biodiversity of the Valasco Valley. Peat bog communities were mainly composed of acidophilous taxa, sometimes planktonic and forming colonies. Epilithic and epiphytic samples did not show significant differences in terms of composition and biodiversity, even though it was statistically possible to identify indicator species for each assemblage. The study also highlighted the presence of several taxa included in the German Red List as endangered or decreasing, especially in the epiphytic samples. Since the water nutrient level and substrate geology were similar among habitats, the main environmental factors shaping Valasco diatom communities were water velocity and pH

Recent findings regarding non-native or poorly known diatom taxa in north-western Italian rivers

Diatoms of the major rivers of North-Western Italy were investigated to highlight the presence of species of particular ecological interest but not as yet recorded. The survey area included streams belonging to seven different hydroecoregions (HERs) with a wide range of physical characteristics. Between 2008 and 2010, 200 samples were taken for the study of the diatom community composition, while a larger set of samples was examined to determine the presence or absence of the nuisance diatom species Didymosphenia geminata (Lyngbye) Schmidt. A specific field study was performed in two rivers characterized by persistent blooms of this species to evaluate the effects of its proliferation on the benthic communities. D. geminata was present in almost 20% of the samples. From a comparison with published data, we can confirm that D. geminata has recently been expanding its ecological range, as it has been found also in mesotrophic lowlands water. In some instances the formation of massive proliferation has been recorded. The calculation of autecological values confirmed its preference for oligotrophic waters with low mineral content and organic loading, although with a wider ecological amplitude than recorded in the first studies on this species. Another four taxa of particular interest were detected: Achnanthidium subhudsonis (Hustedt) Kobayasi (in 15 sites), Cymbella tropica Krammer (11 sites), Mayamaea cahabaensis Morales and Manoylov (2 sites) and Reimeria uniseriata Sala, Guerrero and Ferrario (18 sites). The first three species must be considered new records for Northern Italy. A. subhudsonis and C. tropica reached up to 20% relative abundance. From the analysis of their distribution and autecological values, we can assert that A. subhudsonis and M. cahabaensis show a preference for high values of nitrogen, this latter preferring also quite high values of total phosphorus. C. tropica prefers intermediate values of nitrogen nutrients and R. uniseriata is the least demanding species in terms of water quality. All the taxa studied have a wide ecological range, confirming their potential invasive behaviour. Finally, considerations are provided with respect to Italian and European historical data in order to understand whether these species can be considered non-indigenous and/or bloom forming, in the study area. The results may help improve the process of ecological classification of water bodies in the seven HERs, and the water protection actions introduced by the Water Framework Directive (2000/60)

Suggestions for diatom-based monitoring in intermittent streams

Over the last decades, river lentification processes and droughts have been dramatically spreading worldwide, due to global and local drastic changes due to human activities. Under this scenario, the evaluation of physical disturbance caused by intermittency and droughts has become more and more relevant. In this research, we compare samples collected in Mediterranean streams following both traditional and experimental approaches with the aim of understanding if diatom indices calculated from a new sampling strategy could provide additional information for the physical disturbance assessment. Moreover, we also evaluated the response of functional metrics. Our results demonstrated that even though an enhanced sampling method better reflects hydrological disturbance than the traditional one, diatom indices do not detect it. Conversely, functional traits proved to be important metrics for the hydrological disturbance assessment. In particular, benthic diatom chlorophyll a showed significantly lower values in sections more subject to droughts. With respect to ecological guilds, the motile taxa proved to be linked to depositional areas, which resulted important microhabitats (MHs) to be explored in rivers affected by lentification. Including different MHs in the sampling process improves the information we can obtain from the analysis of the diatom community and presents important implications in documenting species distribution and autecology

Leitura em voz alta na sala de aula: a materialização do texto literário

Este artigo aborda um aspecto importante da didática da leitura literária – a leitura em voz alta. Relata situações de enfrentamento das dificuldades em leitura de alunos do Ensino Fundamental, observadas em pesquisas desenvolvidas em uma turma de 4º ano, de uma escola da Rede Municipal de Ensino de Curitiba, e em turmas de 6º e 7º ano, em uma escola estadual do município de Colombo, região metropolitana de Curitiba. A metodologia de pesquisa utilizada foi a de natureza etnográfica, com ênfase nas observações dos processos pedagógicos desenvolvidos pelas professoras e seus efeitos nos alunos, trazendo à tona o que tem sido e o que precisa ser feito na escola para a formação de leitores de literatura. Constatou-se que a leitura em voz alta em sala de aula mobiliza o imaginário dos alunos, aproxima professor e alunos e proporciona a comunicação entre texto e leitor

Leitura em voz alta na sala de aula: a materialização do texto literário

Este artigo aborda um aspecto importante da didática da leitura literária – a leitura em voz alta. Relata situações de enfrentamento das dificuldades em leitura de alunos do Ensino Fundamental, observadas em pesquisas desenvolvidas em uma turma de 4º ano, de uma escola da Rede Municipal de Ensino de Curitiba, e em turmas de 6º e 7º ano, em uma escola estadual do município de Colombo, região metropolitana de Curitiba. A metodologia de pesquisa utilizada foi a de natureza etnográfica, com ênfase nas observações dos processos pedagógicos desenvolvidos pelas professoras e seus efeitos nos alunos, trazendo à tona o que tem sido e o que precisa ser feito na escola para a formação de leitores de literatura. Constatou-se que a leitura em voz alta em sala de aula mobiliza o imaginário dos alunos, aproxima professor e alunos e proporciona a comunicação entre texto e leitor