-(Cyanobacteria from different types of lakes ("salina", "salitrada" and "baía") representative of the Pantanal da Nhecolândia, MS, Brazil). Considering the ecological importance of cyanobacteria and the scarcity of more precise information about these organisms in the different aquatic systems of the Brazilian Pantanal, our aim is the study of the cyanobacterial flora in three lakes in the Pantanal da Nhecolândia region. The studied lakes are natural water bodies and are shallow (maximum depth 1.1 m), rounded and present different limnological features mainly regardin to the pH and salinity. The samples were collected in the dry and rainy seasons, during 2004-2007. Twenty one species of cyanobacteria were identified. Oscillatoriales was the order with the highest species richness (24% of the total of the identified species), followed by Synechococcales, Pseudanabaenales, Chroococcales and Nostocales, each one contributing with 19%. The lake "Salina do Meio" presents extreme environmental conditions and was the highest species richness system for cyanobacterial (13 species-62%). In this lake, blooms of Anabaenopsis elenkinii Miller were observed, mainly during the dry season. The lakes "Salitrada Campo Dora" (9 species) and "Baía da Sede Nhumirim" (9) presented equals species richness, but the floristic composition was distinct probably due to their different limnological conditions. All the species were referred for the first time to the Brazilian Pantanal.
The taxonomy of four isolated strains of Anabaenopis elenkinii and A. arnoldii from North and South America were investigated using a polyphasic approach. The studied populations were collected from seven alkaline lakes of the Brazilian Pantanal and Nabor Carrillo Lake, Texcoco region (Mexico), between 2004 and 2012, where they frequently formed blooms during the dry season. The morphological plasticity of the populations, from natural and culture conditions, was described based on 200 individuals of each species. The 16S rRNA and the cpc-BA-IGS phylogenetic analyses show Anabaenopsis as a sister-taxon of Cyanospira. The Anabaenopsis clade has three strongly supported subclusters related to the origin of strains: Pantanal+Mexico, Kenya+Australia and one European clade. Although these data indicate that the currently known Anabaenopsis strains belong to more than one species, we are being conservative and not describing them as new species due to the lack of more molecular data. We highlight the need of a revision of the genus, considering also that Anabaenopsis sp. PCC 9215, the current reference strain used for the genus, is not identified as A. elenkinii and it is phylogenetically grouped with Anabaenopsis strains identified as A. circularis, A. arnoldii, A. nadsonii and A. elenkinii.
RESUMOAs lagoas alcalinas do Pantanal da Nhecolândia, denominadas "salinas", são exemplos típicos de ambientes extremos por apresentarem elevados valores de pH (˃9). Este estudo mostrou as particularidades da microflora das "salinas" que é composta por espécies alcalíficas tais como Anabaenopsis elenkinii, Anomoeoneis sphaerophora var. sphaerophora e Nitzschia intermedia. Além disso, foi observado que alterações naturais e/ou antrópicas, que permitem a entrada de água doce de sistemas adjacentes às "salinas", descaracterizam a flora típica desses ambientes. Assim, o presente estudo enfatiza que as características naturais de isolamento das "salinas" devem ser preservadas e que a composição da sua microflora é uma importante ferramenta para avaliar mudanças nestes sistemas. Palavras-chave: Pantanal; lagoas alcalinas; biodiversidade; microflora. ABSTRACTALGAE AND CYANOBACTERIA FROM EXTREME ENVIRONMENT OF THE BRAZILIAN PANTANAL. The alkaline lakes, known as "salinas", in Pantanal are typical examples of extreme environments due to their high pH (>9) values. The present study showed the particularities of the microflora in these alkaline lakes that is composed of alkaliphic species such as Anabaenopsis elenkinii, Anomoeoneis sphaerophora var. sphaerophora and Nitzschia intermedia. Besides, it was detected that natural or anthropogenic disturbances that allowed freshwater from adjacent lakes go into the "salinas", totally modified the typical flora of these systems. Thus, our study indicates that the natural condition of isolation of the alkaline lakes should be preserved and that the composition of its microflora is a very important tool to evaluate the changes in these systems. RESUMEN ALGAS Y CIANOBACTERIAS DE AMBIENTES EXTREMOS DEL PANTANAL BRASILEÑO.Los lagos alcalinos del Pantanal, conocidos como "salinas", son ejemplos típicos de ambientes extremos debido a sus elevados valores de pH (>9). El presente estudio mostró las particularidades de la microflora de estos lagos alcalinos que está compuesta por especies alcalófilas tales como Anabaenopsis elenkinii, Anomoeoneis sphaerophora var. sphaerophora y Nitzschia intermedia. Además, se observó que los disturbios naturales y/o antrópicos, que permiten el ingreso de agua dulce de los sistemas adyacentes a las "salinas", modifican totalmente la flora típica de los estos ambientes. De esta manera, este estudio enfatiza en que las condiciones naturales de aislamiento de las "salinas" debe ser preservado y que la composición de su microflora es una herramienta importante para evaluar los cambios en estos sistemas. Palabras-clave: Pantanal; lagos alcalinos; biodiversidad; microflora.
Anabaenopsis elenkiniiMiller forms bloom in the alkaline shallow lakes of the Brazilian Pantanal. The A. elenkinii CCIBT1059 strain was isolated from one of these alkaline lakes and the experiments were made in growth chamber during 30 days, under modified medium BG-11 (3 % NaNO 3 ), temperature 25 ºC, photoperiod 12-12 light-dark cycle and irradiance of 80-100 µmol photons m -2 s -1 at three different pH values: 7.0, 9.5 and 10.5. In relation to growth rate and cell yield the higher values were observed at pH 10.5. Morphologically, the longest trichomes were found at pH 7 (maximum 45 cells) in comparison with pH 9.5 (maximum 32 cells) and pH 10.5 (maximum 23 cells). The occurrence of heterocytes was observed in all treatments, but akinetes were never formed. The morphometric variability within each treatment between exponential and stationary growth was clearly higher than the variability among different treatments in most cases. Our results indicate that A. elenkinii is typical of alkaline systems and also that in lower pH values the growth limitation can occur in terms of number of cells and biomass. This study represents the first experimental evidence of the effects of pH on growth rate, cell yield and morphometric variability of A. elenkinii.
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