A diversidade específica para a análise das sucessões fitoplanctônicas. Aplicação ao ecossistema da ressurgência de Cabo Frio (RJ).

Extensive qualitative and quantitative data on phytoplankton collected in the Cabo Frio (Brazil) upwelling zone and analysed by Utermohl method were used for calculating Gleason-Margalef, Menhinick, Shannon, Margalef, Simpson inverse and Mac Intosh absolute diversity indices, and the relative indices of Redundancy and Evenness. The relationships between Margalef index and the other indices were studied. Shannon index, mathematically similar to the Margalef index showed the best agreement (r = 0,959); Gleason index is simpler to calculate and is quite satisfactory for a superficial analysis (r = 0,880). The Redundancy calculation is recommended for the interpretation of a single sample. In general, at Cabo Frio, phytoplankton diversity index is rarely less than 1.00 bit.cel“1 even after the enrichment by deep water. The planktonic ecosystem in Cabo Frio maintains a certain level of maturity which may explain the relatively mild nature of the blooms which follow upwelling.A partir de dados quantitativos e qualitativos sobre o fitoplâncton da ressurgência de Cabo Frio (RJ) foram calculados os índices absolutos de diversidade específica de Gleason-Margalef, Menhinick, Shannon, Margalef, inverso de Simpson, Mac Intosh e os índices relativos de Redundância e Uniformidade. Foi realizado um estudo de correlações entre o índice de Margalef e os demais. O índice de Shannon apresentou a melhor correlação (r = 0,959) e o de Gleason, de cálculo bem simples, pode ser considerado satisfatório para uma análise superficial (r = 0,880). O cálculo da Redundância é aconselhado para a análise de uma amostra isolada. Nas águas costeiras de Cabo Frio, o índice de diversidade específica do fitoplâncton é raramente inferior a 1,00 bit.cel'1, mesmo após a fertilização pelas águas profundas. O ecossistema planctônico de Cabo Frio mantém um certo nível de maturidade que pode explicar a fraca intensidade dos florescimentos fitoplanctônicos consecutivos aos efeitos da ressurgência

Environmental and sanitary conditions of guanabara bay, Rio de Janeiro

Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km2. In its surroundings live circa 16 million inhabitants, out of which 6 million live in Rio de Janeiro city, one of the largest cities of the country, and the host of the 2016 Olympic Games. Anthropogenic interference in Guanabara Bay area started early in the XVI century, but environmental impacts escalated from 1930, when this region underwent an industrialization process. Herein we present an overview of the current environmental and sanitary conditions of Guanabara Bay, a consequence of all these decades of impacts. We will focus on microbial communities, how they may affect higher trophic levels of the aquatic community and also human health. The anthropogenic impacts in the bay are flagged by heavy eutrophication and by the emergence of pathogenic microorganisms that are either carried by domestic and/or hospital waste (e.g., virus, KPC-producing bacteria, and fecal coliforms), or that proliferate in such conditions (e.g., vibrios). Antibiotic resistance genes are commonly found in metagenomes of Guanabara Bay planktonic microorganisms. Furthermore, eutrophication results in recurrent algal blooms, with signs of a shift toward flagellated, mixotrophic groups, including several potentially harmful species. A recent large-scale fish kill episode, and a long trend decrease in fish stocks also reflects the bay’s degraded water quality. Although pollution of Guanabara Bay is not a recent problem, the hosting of the 2016 Olympic Games propelled the government to launch a series of plans to restore the bay’s water quality. If all plans are fully implemented, the restoration of Guanabara Bay and its shores may be one of the best legacies of the Olympic Games in Rio de Janeiro

Massive Blooms of Chattonella subsalsa Biecheler (Raphidophyceae) in a Hypereutrophic, Tropical Estuary—Guanabara Bay, Brazil

Cell concentrations of the potentially harmful raphidophyte Chattonella subsalsa Biecheler were quantified in surface waters of Guanabara Bay, a heavily eutrophicated estuarine system in tropical Brazil, from February 2014 to January 2018. Cells were imaged and quantified in live samples by means of an automated imaging system (FlowCam®). Bloom episodes (>0.1 × 106 cells L−1) were observed in 37 samples, mostly in a shallow (<10 m) area with extremely high nutrient and organic matter loads (average total P = 19 μM and total N = 344 μM), intermediate salinity (average 24.5), and low water transparency (average Secchi depth = 0.54 m) due to continental runoff. Blooms in this area reached up to 13.3 × 106 cells L−1. C. subsalsa cell concentration was correlated with parameters linked to eutrophication of the bay. On a monthly basis, C. subsalsa abundance was correlated with a period of positive Multivariated El Niño/Southern Oscilation Index (MEI) that lasted from the beginning of 2015 to mid-2016 (known as Godzilla El Niño), indicating a potential influence of regional climate on the occurrence of C. subsalsa. Notably, at least six fish kill episodes were reported in the Bay during this period which, added to the toxicity of C. subsalsa strains isolated from the bay to Artemia nauplia (48h-LC50 = 7.3 × 106 cells L−1), highlights the threat that this HAB species poses to the environment. This is the first report of recurrent, massive C. subsalsa blooms in Guanabara Bay. Regardless of the influence of climatic forcing in favoring C. subsalsa development, reducing nutrient loads would be the best strategy to mitigate blooms of this and other potentially harmful algae in Guanabara Bay

Environmental and sanitary conditions of Guanabara Bay, Rio de Janeiro

Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km2. In its surroundings live circa 16 million inhabitants, out of which 6 million live in Rio de Janeiro city, one of the largest cities of the country, and the host of the 2016 Olympic Games. Anthropogenic interference in Guanabara Bay area started early in the XVI century, but environmental impacts escalated from 1930, when this region underwent an industrialization process. Herein we present an overview of the current environmental and sanitary conditions of Guanabara Bay, a consequence of all these decades of impacts. We will focus on microbial communities, how they may affect higher trophic levels of the aquatic community and also human health. The anthropogenic impacts in the bay are flagged by heavy eutrophication and by the emergence of pathogenic microorganisms that are either carried by domestic and/or hospital waste (e.g. virus, KPC-producing bacteria, and fecal coliforms), or that proliferate in such conditions (e.g. vibrios). Antibiotic resistance genes are commonly found in metagenomes of Guanabara Bay planktonic microorganisms. Furthermore, eutrophication results in recurrent algal blooms, with signs of a shift towards flagellated, mixotrophic groups, including several potentially harmful species. A recent large-scale fish kill episode, and a long trend decrease in fish stocks also reflects the bay’s degraded water quality. Although pollution of Guanabara Bay is not a recent problem, the hosting of the 2016 Olympic Games propelled the government to launch a series plans to restore the bay’s water quality. If all plans are fully implemented, the restoration of Guanabara Bay and its shores may be one of the best legacies of the Olympic Games in Rio de Janeiro