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This study analyzes the abundance, diversity, species richness, and evenness of phytoplankton in the Esteros del Iberá (Argentina) under two contrasting climatic conditions, encompassing both lentic and lotic environments. Analyses revealed that phytoplankton abundance in most of the Iberá system environments is unaffected by climatic variability; however, diversity, species richness, and evenness of phytoplankton were modified. In the large shallow lakes, Cyanobacteria predominated as components of the phytoplankton, with the highest density values in lagoon Iberá during the dry period. Two of the cyanobacteria species identified (Raphidiopsis raciborskii y Microcystis aeruginosa) are bloom-forming and potential producers of cyanotoxins, thus early detection of harmful species and sustainable management actions are recommended for tourist and conservation activities. [ABSTRACT FROM AUTHOR]

Knowing the biodiversity is extremely important in the application of conservation and management plans. Thus, the occurrence of continental cyanobacteria and micro and macroscopic algae was recorded in Ceará (northeast of Brazil), a state that is among the ones with the least knowledge of the phycological flora in the country. A bibliographic survey was carried out in specialized literature and in consultations on species distribution databases in Ceará. A total of 605 taxa were recorded for the phycological flora of Ceará, with Bacillariophyceae, Cyanophyceae and Chlorophyceae being the most representative classes. The cyanobacteria Microcystis aeruginosa (Kützing) Kützing was the species with the highest occurrence in publications and the diatom Cyclotella meneghiniana Kützing the species with the highest distribution record among the ecosystems studied. The genera with the highest number of recorded species were the diatoms Eunotia, Gomphonema and Nitzschia. It was observed that the predominance of the analyzed studies focused on phytoplanktonic algae, predominantly in studies with an ecological approach, conducted in reservoirs and published in greater numbers in the last decade. This study will contribute to the addition of information about the Brazilian phycological diversity and becomes a starting point for works that seek a greater taxonomic refinement of the species that occur in the state of Ceará. [ABSTRACT FROM AUTHOR]

Lead is a heavy metal that, due to its physicochemical properties, defines it as a bioaccumulative, persistent and toxic contaminant in soil and water bodies. Bioremediation is a sustainable and ecological alternative for the removal of this contaminant. Microorganisms such as Spirulina platensis and Pseudomonas aeruginosa are widely used for their ability to bioadsorb lead, therefore, the objective of this research was to evaluate the bioremoval potential of lead in a photobioreactor by both microorganisms in a free state and immobilized with calcium alginate. Three different concentrations of 10, 20 and 30 mg/L of lead nitrate were used, Hoagland medium was used with Spirulina platensis and CASO broth with Pseudomonas aeruginosa. The ANOVA statistical test showed that there is no significant difference in the concentration of chlorophyll “a” between the different treatments with Spirulina platensis, however, there is a significant difference in the percentage of elimination between both microorganisms, but, the Tukey test, It stands out that there is no difference in the media between the treatments with Spirulina platensis, Pseudomonas aeruginosa and Spirulina consortium with Pseudomonas, therefore, the difference lies in the bioadsorption capacity in different concentrations of lead nitrate. The authors infer that both microorganisms are exceptional for the removal of this contaminant, however, it is necessary to perform more tests under different conditions. [ABSTRACT FROM AUTHOR]

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A Microcystis aeruginosa bloom occurred in the Planetario Lake (Parque Tres de Febrero, Ciudad Autónoma de Buenos Aires, Argentina) that led to the restoration of the lake. Before and after the restoration (since October 1999 to September 2000), samples were collected to assess changes in the phytoplankton structure. The genus Interfilum (Chlorococcales, Chlorophyta) was recorded in the samples for February and May 2000 for the first time in America. Furthermore, it is a new variety for science: I. paradoxum var regulare var. nov. [ABSTRACT FROM AUTHOR]

Between July of 1992 and August of 1993 and with the purpose of studying the hydrologic characteristics of two water columns in the Peñol-Guatapé Reservoir, monthly sampling in the reservoir's tail were carried out and in open water (Isla del sol). In each station and at five depths, some physical and chemical variables were analyzed; and in the fotic zone, the phytoplankton community was studied, excluding the Diatomophyceae group. Thermal and chemical gradients were found in the two stations and from the hydro-biological point of view, the quality of water was oligomesotrofic. The primary production was low during the entire period of sampling, and just as the other variables, it was deeply influenced by the variation in the reservoir levels at the time of study. [ABSTRACT FROM AUTHOR]