Priscila Izabel Tremarin

Diatomáceas perifíticas em um sistema eutrófico brasileiro (Reservatório do Iraí, estado do Paraná)

O estudo sobre a diversidade das diatomaceas do reservatorio do Irai ampliou o conhecimento da flora diatomologica perifitica de ambientes eutroficos do estado do Parana e contribuiu para subsidiar futuros trabalhos que utilizem diatomaceas como bioindicadoras das condicoes troficas da agua. Coletas trimestrais foram realizadas no reservatorio durante um ano. As amostras perifiticas foram obtidas pela remocao do biofilme aderido a caules da macrofita Polygonum sp. e a lâminas de vidro. Estas foram colocadas em complexos de madeira e deixadas submersas durante 30 dias para colonizacao. O estudo taxonomico resultou na identificacao de 11 citacoes pioneiras para o estado do Parana entre as 96 especies de diatomaceas determinadas. Maior diversidade de especies foi registrada para o substrato macrofita. Achnanthidium minutissimum foi dominante na maior parte das amostras analisadas, sendo considerada tolerante as condicoes eutroficas do reservatorio do Irai. Fragilaria rumpens, Fragilaria vaucheriae var. capitellata e Gomphonema gracile foram abundantes. Informacoes ecologicas sobre as especies foram obtidas em literatura, sendo 35% caracteristicas de sistemas aquaticos em processo avancado de eutrofizacao, 18% de ambientes mesotroficos e 19% classificadas como tolerantes e indiferentes ao estado trofico dos ambientes.

Eunotia Ehrenberg (Bacillariophyceae) do rio Guaraguaçu, litoral do Paraná, Brasil

The survey is a inventory floristic of Eunotiaceae family from Guaraguacu river, one of the important lotic ecosystems of Litoranea watershed, State of Parana, South Brazil. Samples were collected on April and October of 2003 from plankton and periphyton at six localities along the river. Forty species were identified and 16 taxa were registered for first time to State of Parana: Eunotia anamargaritae,E. auriculata, E. batavica, E. convexa var. convexa f. impressa, E. dacostae,E. denticulata,E. fallax var. groenlandica, E. herzogii,E. meridiana, E. muscicola var. tridentula,E. nymanniana, E. pseudoindica, E. trinacria, Eunotia sp. 2, Eunotia sp. 3 and Eunotia sp. 4.

Diatoms (Bacillariophyceae) of Iguaçu National Park, Foz do Iguaçu, Brazil

This study represents a taxonomic survey of class Bacillariophyceae diatoms found in samples collected in the Iguacu River (Iguacu National Park, municipality of Foz do Iguacu, in the state of Parana, Brazil) between August 2007 and July 2008. Two sampling stations were utilized, the first located upstream of Iguacu Falls (Cais Bananeiras Station) and second downstream of the falls (Cais Macuco Safari Station). The study resulted in the identification of 86 taxa, including 74 at the specific level and seven taxonomic varieties. Two of these had never before been documented in the state of Parana: Gomphonema gibberum Hustedt and Pinnularia meridiana Metzeltin & Krammer. Nine are first-time records for Brazil: Cymbella charrua Metzeltin, Lange-Bertalot & Garcia-Rodriguez, Placoneis ovillus Metzeltin, Lange-Bertalot & Garcia-Rodriguez, Gomphonema affinopsis Metzeltin, Lange-Bertalot & Garcia-Rodriguez, , Gomphosphenia lingulatiformis (Lange-Bertalot & Reichardt) Lange-Bertalot, Luticola aequatorialis (Heiden) Lange-Bertalot & Ohtsuka, Sellaphora garciarodriguezii Metzeltin & Lange-Bertalot, Eolimna submuralis (Hustedt) Lange-Bertalot Kulikovskiy, Geissleria neosubtropica Metzeltin, Lange-Bertalot & Garcia-Rodriguez and Stauroneis cf. sylviabonillae Metzeltin, Lange-Bertalot & Garcia-Rodriguez.

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

Periphytic diatoms on Potamogeton polygonus Cham. & Schltdl.: first records from Parana State. A taxonomic study of periphytic diatoms associated to aquatic macrophyte Potamogeton polygonus was carried out. Specimens were collected on February, May and November/2005 and March/2006, in an artificial lagoon and in the Salto Amazonas river, located at General Carneiro, Parana State. Based on the analysis of permanent slides with cleaned periphytic samples, one hundred and forty-seven taxa had been registered, 55 diatoms were exclusive of the lentic environment, 34 of the lotic environment and 58 occurred on both ones. The most representative families were Eunotiaceae (13.6%), Pinnulariaceae (11.6%) and Naviculaceae (9.6%). The genera with greater number of species and varieties were Eunotia with 20 taxa and Pinnularia with 17. The study contributed with 18 new registers to the state, and was pioneer to document forms of diatom attachment on aquatic macrophyte of systems lotic and lentic in the Parana state.

Thalassiosirales (Diatomeae) do rio Guaraguaçu, Bacia Litorânea, PR, Brasil

The floristic inventory of Thalassiosirales from Guaraguacu river was based on planktonic and periphytic samples collected at six sampling stations throughout the river, considering a salinity gradient. A total of 28 species were identified with 19 included in Thalassiosiraceae family. Among the diatoms recorded, 85,7% were marine/estuarine and 14,3% were continental species. Cyclotella atomus Hustedt, C. choctawhatcheeana Prasad, Thalassiocyclus lucens (Hustedt) Hakansson & Mahood, Thalassiosira minima Gaarder, T. prochkinae Makarova, T. pseudonana Hasle & Heimdal, T. tealata Takano, T. tenera Proschkina-Lavrenko and Thalassiosira sp. were the nine new records for the State of the Parana. Identification keys, taxonomic descriptions, measurements, MO and MEV illustrations complement the study.

THALASSIOSIRA RUDIS SP. NOV. (COSCINODISCOPHYCEAE): A NEW FRESHWATER SPECIES

The centric diatom Thalassiosira rudis sp. nov. has been described by morphological and ultrastructural analyses of the frustules using light and scanning electron microscopy. The species was found in the freshwater ecosystems from Brazil. T. rudis is characterized by a convex valve face sunken in the middle and downturned at mantle, wider central areolae, internal opening of cribra branched in dichotomic rows, absence of central processes, 1–3 marginal rimoportulae, presence of marginal ring of fultoportulae with inward extension furnished with cowlings and very short external tube, cingulum composed of four or more open bands, singly and alternately septate, and valvocopulae with one row of larger poroids. The new species was compared morphologically with closely related species ofThalassiosirasuch as T. gracilis (Karsten) Hustedt, T. visurgis Hustedt and T. rudolfii (Bachman) Hasle. Comments about T. weissflogii (Grunow) Fryxell & Hasle and T. leptopus (Grunow) Hasle & Fryxell were presented.

Ecology and distribution of Aulacoseira species (Bacillariophyta) in tropical reservoirs from Brazil

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.

Ultrastructure and distribution of Aulacoseira gessneri

Aulacoseira gessneri (Hustedt) Simonsen has been mentioned rarely in the literature and its ultrastructure has not yet been investigated. The species was originally described from an Amazonian river, and its occurrence is still restricted to Brazilian environments. Specimens, found in Pantanal of Mato Grosso eutrophic lakes, were described and illustrated using optical and electron microscopy, and its morphology compared with similar species, A. distans (Ehrenberg) Simonsen and A. muzzanensis (Meister) Krammer. Aulacoseira gessneri presented the following diacritical characteristics: long filaments joined by small connection spines, elongated separation spines, valve mantle ornamented by straight striae composed of areolae usually round, ringleiste poorly developed, and row of sessile rimoportulae near the collum. The species reached high biomass (11–12 mg L−1) both during the high and low water periods in Pantanal lakes.

Aulacoseira calypsi sp. nov. (Coscinodiscophyceae) from an Amazonian lake, northern Brazil

This paper describes a new diatom species, Aulacoseira calypsi Tremarin, Torgan & Ludwig, from specimens in plankton samples from Água Preta lake. This Amazonian lake is a shallow mesotrophic environment situated in northern Brazil. The species is characterized by long filaments united by spatulate linking spines, obovate to conic separation spines, a valve surface variably ornamented, straight striae on the mantle, a narrow ringleist, and one row of sessile rimoportulae near the ringleist. Aulacoseira calypsis morphometric features are compared with the following similar species: Aulacoseira nygaardii (Camburn) Camburn & Charles, Aulacoseira lacustris (Grunow) Krammer, Aulacoseira coroniformis Pearce & Cremer, Aulacoseira occulta Siver & Hamilton, Aulacoseira lancea Siver & Hamilton, Aulacoseira gessneri (Hustedt) Simonsen, and Aulacoseira islandica (Müller) Simonsen. The species shares similarities as to frustule size, striation pattern, and narrowness of ringleist; but differs in the morphology of separation and linking spines, and the number and position of the rimoportulae.

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

A taxonomic study is presented of the predominant periphytic diatoms from three streams, Nazare, Guaiapo and Remo, influenced by different anthropogenic actions. Samples were taken bimonthly in three sites of the stream watercourse, headwater, middle and mouth, from July 2007 to August 2008. Twenty six predominant species was recorded, from a total of 151 identified diatoms in the analyzed samples. Seven species were abundant or dominant in the three studied streams: Eolimna minima (Grunow) Lange-Bertalot (dominant in Remo stream), Gomphonema lagenula Kutzing (dominant in Guaiapo stream), Gomphonema pumilum (Grunow) Reichardt & Lange-Bertalot and Nupela praecipua (Reichardt) Reichardt (both dominant in Nazare stream), Geissleria aikenensis (Patrick) Torgan & Oliveira, Nitzschia palea (Kutzing) Smith and Sellaphora seminulum (Grunow) Mann (abundant in three streams). Two species were abundant exclusively in Nazare urban stream, 13 in Remo rural streams and six in Guaiapo stream that is influenced by both environments.