Cosmarium Corda ex Ralfs (Desmidiaceae) em um lago artificial urbano, Paraná, Brasil

The aim of this work is the taxonomic survey of species of the genus Cosmarium from Lago Municipal de Cascavel, Paraná. Samples collections were carried out between 2002 to 2003, 2007 and 2008, in the lake littoral zone with phytoplankton net. Eighteen taxa were identified, described and illustrated, which three species, fifteen varieties and one forms a taxonomic. Nine taxa (50%) of total were first cited to the Paraná State: C. denticulatum Borge var.  ovale, C. depressum (Nägeli) Lundell var. elevatum Borge, C. galeritum Nordstedt var. galeritum, C. montrealense Croasdale, C. pseudopyramidatum P. Lundell var. pseudopyramidatum, C. pseudopyramidatum var. maximum Börgesen, C. quadrum Lundell var. minus Nordstedt, C. regnellii Wille var. regnellii e C. variolatum Raciborski var. cataractarum.O objetivo deste trabalho foi o levantamento taxonômico das espécies do gênero Cosmarium no Lago Municipal de Cascavel, Paraná. As coletas foram realizadas nos anos de 2002 a 2003 e 2007 a 2008, na região litorânea do lago, utilizando-se uma rede de plâncton. Foram identificados, descritos e ilustrados dezoito táxons, sendo três espécies, quinze variedades e uma forma taxonômica. Do total, nove táxons (50%) são citados pela primeira vez para o Estado do Paraná: C. denticulatum Borge var.  ovale, C. depressum (Nägeli) Lundell var. elevatum Borge, C. galeritum Nordstedt var. galeritum, C. montrealense Croasdale, C. pseudopyramidatum P. Lundell var. pseudopyramidatum, C. pseudopyramidatum var. maximum Börgesen, C. quadrum Lundell var. minus Nordstedt, C. regnellii Wille var. regnellii e C. variolatum Raciborski var. cataractarum

Chlorophyceae e Trebouxiophyceae (Chlorophyta) em ambientes lóticos na área de influência da Usina Hidrelétrica do Baixo Iguaçu, Estado do Paraná, Brasil

The presence of microscopic algae of the classes Chlorophyceae and Trebouxiophyceae in lotic environments stands out for its high morphologic diversity and its capacity to indicate the quality of the water. This study had the objective of accomplishing the taxonomic survey of rivers from the area of influence of Baixo Iguaçu’s hydroelectric power plant. The monthly samples were collected from january of 2019 to december of 2019 allowing the identification of 55 taxons, distributed in eight families Hydrodictyaceae, Scenedesmaceae, Selenastraceae, Sphaeropleaceae, Volvocaceae, Chlorellaceae, Oocystaceae and Trebouxiophyceae incertae sedis. Between the identified taxa, 12 are new citations for Paraná State: Monactinus simplex var. echinulatum (Wittrock) Pérez, Monactinus simplex var. sturmii (Reinsch) Pérez, Pseudopediastrum boryanum var. longicorne (Reinsch) Tsarenko, Desmodesmus lefevrei (Deflandre) S.S.An, T.Friedl & E.H.Hegewald, Desmodesmus opoliensis var. carinatus (Lemmermann) E.Hegewald, Desmodesmus perforatus (Lemmermann) E.Hegewald, Pectinodesmus javanensis (Chodat) E.Hegewald, Scenedesmus acunae Comas Gonzáles, Quadrigula closterioides (Bohlin) Printz, Volvox globator Linnaeus, Actinastrum aciculare f. minimum (Huber-Pestalozzi), Actinastrum hantazschii var. subtile Woloszynska.A presença de microalgas das classes Chlorophyceae e Trebouxiophyceae em ambientes lóticos se destaca por sua alta diversidade morfológica e sua capacidade de indicar a qualidade da água. Este trabalho objetivou realizar o levantamento taxonômico em rios da área de influência da Usina Hidrelétrica do Baixo Iguaçu. As amostragens mensais foram realizadas de janeiro de 2019 a dezembro de 2019 possibilitando a identificação de 55 táxons, distribuídos em oito famílias Hydrodictyaceae, Scenedesmaceae, Selenastraceae, Sphaeropleaceae, Volvocaceae, Chlorellaceae, Oocystaceae e Trebouxiophyceae incertae sedis. Dentre os táxons identificados, 12 são novas citações para o Estado do Paraná: Monactinus simplex var. echinulatum (Wittrock) Pérez, Monactinus simplex var. sturmii (Reinsch) Pérez, Pseudopediastrum boryanum var. longicorne (Reinsch) Tsarenko, Desmodesmus lefevrei (Deflandre) S.S.An, T.Friedl & E.H.Hegewald, Desmodesmus opoliensis var. carinatus (Lemmermann) E.Hegewald, Desmodesmus perforatus (Lemmermann) E.Hegewald, Pectinodesmus javanensis (Chodat) E.Hegewald, Scenedesmus acunae Comas Gonzáles, Quadrigula closterioides (Bohlin) Printz, Volvox globator Linnaeus, Actinastrum aciculare f. minimum (Huber-Pestalozzi), Actinastrum hantazschii var. subtile Woloszynska

The variability in the hydrosedimentological regime supports high phytoplankton diversity in floodplain: A 12-year survey of the Upper Paraná River

The alpha, beta, and gamma diversity are important tools for conservation studies, and the distribution of species in space and time is essential to provided insights regarding diversity patterns and processes that modify the ecosystem and the community responses to such changes. Thus, a long-term ecological date was used to evaluate in 12 biotopes the phytoplankton composition and diversity within selected habitats (alpha diversity), between habitats (beta diversity) and across the upper Paraná River floodplain (gamma diversity). We evaluate the environmental variability of the hydrosedimentological cycles (limnophase and potamophase) during 12 years, associated with the water level variability and with the environmental heterogeneity as drivers of the phytoplankton composition and diversity in the upper Paraná River floodplain. Remarkable gamma diversity was recorded especially in limnophase, however, years with intense flood presented high gamma diversity, and years with extreme drought presented low gamma diversity, although without significant differences. The alpha diversity was significantly different on spatial and temporal scales. The beta diversity showed high values, however with low temporal variability and without correlation with the hydrosedimentological regime of the Paraná River. Overall, these results indicate that the variability in the hydrosedimentological regime associated with the periodicity, duration, and amplitude of limnophase and potamophase, and the pattern of mosaic of habitats in this floodplain are essential for sustaining much of the diversity phytoplankton diversity and ecosystem integrity, and that this approach is relevant and proved be useful to understand floodplain systems and associated phytoplankton community.</p