Ecological preferences and distribution of Aulacoseira species in southeastern Brazilian reservoirs with varying trophic states were studied. One hundred and fourteen plankton samples (winter and summer) from 57 sites located in 16 reservoirs were analysed. Ten water quality parameters were measured. Ten Aulacoseira species were identified using light, scanning and transmission electron microscopy, and new information on their ecological preferences is provided here. Our results indicate that trophic gradient is the main driver of species distribution. Principal components analysis and calculation of weighted average nutrient optima revealed three indicator taxa, Aulacoseira tenella characteristic for oligotrophic waters and two varieties of Aulacoseira granulata (nominate and var. angustissima) typical for eutrophic reservoirs. This is the first ecological study of Aulacoseira in Brazil, adding information on the distribution of this genus in the tropics, and highlighting the need for species-level identification and regional studies to improve the use of diatoms in water quality assessment.
Th is study represents a taxonomic survey of class Bacillariophyceae diatoms found in samples collected in the Iguaçu River (Iguaçu National Park, municipality of Foz do Iguaçu, in the state of Paraná, Brazil) between August 2007 and July 2008. Two sampling stations were utilized, the fi rst located upstream of Iguaçu Falls (Cais Bananeiras Station) and second downstream of the falls (Cais Macuco Safari Station). Th e study resulted in the identifi cation of 86 taxa, including 74 at the specifi c level and seven taxonomic varieties.
Levantamento dos representantes da família Pinnulariaceae (Naviculales, Bacillariophyceae) do Parque Estadual das Fontes do Ipiranga, São Paulo, Brasil. Foram identificados dois gêneros (Caloneis com 1 e Pinnularia com 12 espécies) e 20 táxons no total, distribuídos em 13 espécies e sete variedades não típicas de suas respectivas espécies. Uma variedade, Pinnularia brauniana (Grunow) Mills var. sanctipaulensis Rocha, é descrita como nova para a ciência. Pinnularia brauniana (Grunow) Mills var. sanctipaulensis Rocha e P. subgibba Krammer var. lanceolata Gaiser & Johanser são, geograficamente, as espécies mais bem distribuídas no PEFI por ocorrerem em 5 localidades cada; e Caloneis hyalina Hustedt, Pinnularia biceps Gregory var. biceps, P. grunowii Krammer, P. joculata (Manguin) Krammer, P. schoenfelderi Krammer, P. subanglica Krammer, P. tabellaria Ehrenberg e P. viridis (Nitzsch) Ehrenberg var. viridis as menos bem representadas, por ocorrerem em uma localidade apenas cada uma.
The diatom flora of the shallow lakes in the Pantanal of Nhecolândia is poorly known. Thus, our aim was to know the diatom biodiversity in three types of shallow lakes called "baías, salitradas and salinas", characterized by differences in pH, electrical conductivity, contact with the coalescent system and the presence of macrophytes. The samples were collected in dry and rainy seasons, from 2004 to 2007. For taxonomic identification, the material was cleaned with H 2 O 2 and analyzed using light microscopy. A total of 23 diatom species were identified and each lake presented a unique species richness and composition. The greatest species richness was found in the Baía da Sede Nhumirim (21 species), followed by the Salitrada Campo Dora (8 species) and finally the lowest species richness was observed in the Salina do Meio (3 species). Only Anomoeoneis sphaerophora Pfitzer var. sphaerophora and Craticula cf. buderi (Hustedt) Lange-Bertalot occurred in the three studied systems. Except for Eunotia binularis (Ehrenberg) Souza and Aulacoseira ambigua (Grunow) Simonsen, all the others are new records to the Brazilian Pantanal. Keywords: biodiversity; brackish water; freshwater; tropical wetland. RESUMODIATOMÁCEAS DE LAGOS RASOS DO PANTANAL DA NHECOLÂNDIA, ÁREA ÚMIDA BRASILEIRA. A flora de diatomáceas dos lagos rasos do Pantanal da Nhecolândia é pouco conhecida. Portanto, nosso objetivo foi conhecer a biodiversidade de diatomáceas que ocorrem em três diferentes tipos de lagoas denominadas de "baías, salitradas e salinas", caracterizadas por diferenças de pH, condutividade elétrica, contato com o sistema coalescente e presença de macrófitas. As amostras foram coletadas nos períodos de cheia e de seca, durante os anos 2004 a 2007. O material foi submetido à limpeza com água oxigenada (H 2 O 2 ) e analisado ao microscópio óptico para se proceder à identificação taxonômica. No total foram identificadas 23 espécies de diatomáceas e cada lagoa apresentou riqueza e composição de espécies distintas. A maior riqueza de espécies foi encontrada na Baía da Sede Nhumirim (21), seguida da Salitrada Campo Dora (8) e a Salina do Meio apresentou a menor riqueza de espécies (3). Somente Anomoeoneis sphaerophora Pfitzer var. sphaerophora e Craticula cf. buderi (Hustedt) Lange-Bertalot foram comuns aos três sistemas estudados. Com exceção de Eunotia binularis (Ehrenberg) Souza e Aulacoseira ambigua (Grunow) Simonsen, as demais espécies são citadas pela primeira vez para o Pantanal brasileiro. Palavras-chave: biodiversidade; água doce; água salobra; áreas úmidas tropicais. RESUMEN DIATOMÁCEAS DE LOS LAGOS RASOS DEL PANTANAL DENHECOLÂNDIA, ÁREA HÚMEDA BRASILERA. La flora de diatomeas de los lagos rasos del Pantal de Nhecolândia es poco conocida. Por lo tanto, nuestro objetivo fue conocer la biodiversidad de diatomáceas que ocurren en tres diferentes tipos de lagos rasos denominados de "baías, salitradas e salinas" caracterizadas por diferencias en el pH, la conductividad eléctrica, contacto con el sistema coalescente y la presencia ...
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