Cyanobacterial occurrence and detection of microcystins and saxitoxins in reservoirs of the Brazilian semi-arid

Fonseca, Jessica Roberts; Vieira, Pryscila Cynara Soares; Kujbida, Paula; Costa, Ivaneide Alves Soares da

doi:10.1590/s2179-975x2814

Cited by 31 publications

(23 citation statements)

References 64 publications

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“…High levels of total phosphorus and biomass of potentially toxic cyanobacteria were also found. In this condition of drastic reduction of water volume and high turbidity, our results evidenced the permanence and high eutrophic state and the dominance of cyanobacteria in the five reservoirs studied, reinforcing the results obtained in other studies carried out in the same reservoirs (Fonseca et al, 2015;Vieira et al, 2015;Panosso et al, 2007;Eskinazi Sant'Anna et al, 2013;Costa et al, 2009). In the same way, this same scenario is configured in studies carried out in other reservoirs located in the same basin (Freitas et al, 2011;Bezerra, 2011;Medeiros et al, 2015).…”

Section: Discussionsupporting

confidence: 91%

“…Further evidence of the influence of the hydrological regime of semi-arid region on the composition and dominance of cyanobacteria is shown by Medeiros et al (2015), Braga et al (2015) and Costa et al (2016). Other phytoplankton studies carried out in eutrophic reservoirs in the Brazilian Northeast, reveal the occurrence of potentially toxic species bloom-forming such as Cylindrospermopsis raciborskii, Microcystis aeruginosa and Planktothrix agardhii (Medeiros et al, 2015;Costa et al, 2006aCosta et al, , b, 2009 and the presence of their toxins (microcystins and saxitoxins) in these environments is reported by Fonseca et al (2015) and Costa et al (2006a). Such studies are important because they contribute to establish conditions and make predictions of future scenarios of the phytoplankton behavior in regions affected drastically by prolonged droughts, contributing to the management of water for the population.…”

Section: Introductionmentioning

confidence: 90%

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Phytoplankton scenario and microcystin in water during extreme drought in semiarid tropical water supplies, Northeastern Brazil

2020

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Abstract The objective of this study was to characterize the limnological, microystin and phytoplankton community of five tropical eutrophic reservoirs located in the Brazilian northeastern semi-arid region, used for domestic use at the time of extreme drought and reduction of water volume. The study was conducted in July and August 2015, and an integrated sample of the water column was collected at three points near the dam in each reservoir. Analysis of limnological parameters, identification and quantification of phytoplankton, with emphasis on cyanobacteria were performed, as well as detection of microcystin by means of immunoassay (ELISA). The reservoirs presented ~ 90% water volume reduction. High turbidity and concentrations of nitrogen and phosphorus, as well as high cyanobacterial densities, revealed an increase in the eutrophic state for hypereutrophy. The total biovolume of phytoplankton and cyanobacterial density is high, plus an average increase in relation to previous studies of 350% and 150%, respectively. The density of cyanobacteria and microcystin concentration presented values above acceptable levels for drinking water according to Brazilian legislation. A phytoplankton community was represented by 17 functional groups, including potentially toxic cyanobacteria species such as Planktothrix agardhii (S1), Microcystis aeruginosa (M), Anabaena planktonica e Anabaena spp. (H1), Cylindrospermopsis raciborskii (Sn). Our results confirm that conditions of extreme drought and reduction of the volume of the reservoirs influence the composition, biovolume of phytoplankton and water quality, but not the increase of total microcystin in the analysed, although above 1μg-1 registered a significant decrease of water quality in used for human consumption.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 90%

Phytoplankton scenario and microcystin in water during extreme drought in semiarid tropical water supplies, Northeastern Brazil

2020

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“…www.jlimnol.it cylindrospermopsin (Bittencourt-Oliveira et al, 2011, saxitoxins (Molica et al, 2002;Fonseca et al, 2015;Lopes et al, 2015), and anatoxin-a(S) (Molica et al, 2005).…”

Section: Accepted Articlementioning

confidence: 99%

Cyanobacterial blooms in freshwaters bodies in a semiarid region, northeastern Brazil: A review

2017

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Harmful cyanobacterial blooms have caused several problems in freshwater environments due to their prolific growth and the harmful cyanotoxins produced by some species. The occurrence of these organisms has increased in recent decades due to climate change and eutrophication, although most studies are from temperate regions in the Northern hemisphere. This review presents data about cyanobacteria occurrence, dominance, and toxicity events in freshwater bodies in a semiarid region of Northeast Brazil, in the tropical Southern hemisphere. We performed a literature survey of cyanobacteria publications from 1930 to 2016. We made a list of all the dominant species registered in each state, noted their distribution and occurrence of dominance events involving one or more species, and the registered records of toxic blooms, including information about the toxins involved and the range of values. We selected 102 publications that described cyanobacteria Accepted Article www.jlimnol.it occurrence from states in Northeast Brazil; these publications included relevant contributions regarding cyanobacteria distribution, richness, density, and biomass. Forty-nine dominant species were recorded, with the most representation found in the state of Pernambuco (30 spp.). The genera with the highest occurrences were Microcystis, Cylindrospermopsis, Planktothrix, Dolichospermum (=Anabaena), and Geitlerinema, especially the species Cylindrospermopsis raciborskii, Microcystis aeruginosa, and Planktothrix agardhii. Episodes of toxic blooms were observed in four states. Microcystins, cylindrospermopsin, saxitoxins, and anatoxin-a(S) were found to be associated with these blooms. In Northeast Brazil, harmful cyanobacterial blooms are common in urban and public reservoirs. However, in recent years, cyanobacterial blooms in this region have been more intense and perennial, with high biomass occurring throughout the year.

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“…The amount of STX usually found in reservoirs of the Brazilian semi-arid region varied between 0.003 and 0.766 μg/L, depending on the period of the year [21]. In 2000, during a toxic bloom at the northeast state of Rio Grande do Norte, R. raciborskii represented 90-100% of total phytoplankton species [22].…”

Section: Introductionmentioning

confidence: 99%

The cyanobacterial saxitoxin exacerbates neural cell death and brain malformations induced by Zika virus

et al. 2020

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The northeast (NE) region of Brazil commonly goes through drought periods, which favor cyanobacterial blooms, capable of producing neurotoxins with implications for human and animal health. The most severe dry spell in the history of Brazil occurred between 2012 and 2016. Coincidently, the highest incidence of microcephaly associated with the Zika virus (ZIKV) outbreak took place in the NE region of Brazil during the same years. In this work, we tested the hypothesis that saxitoxin (STX), a neurotoxin produced in South America by the freshwater cyanobacteria Raphidiopsis raciborskii, could have contributed to the most severe Congenital Zika Syndrome (CZS) profile described worldwide. Quality surveillance showed higher cyanobacteria amounts and STX occurrence in human drinking water supplies of NE compared to other regions of Brazil. Experimentally, we described that STX doubled the quantity of ZIKV-induced neural cell death in progenitor areas of human brain organoids, while the chronic ingestion of water contaminated with STX before and during gestation caused brain abnormalities in offspring of ZIKV-infected immunocompetent C57BL/6J mice. Our data indicate that saxitoxin-producing cyanobacteria is overspread in water reservoirs of the NE and might have acted as a co-insult to ZIKV infection in Brazil. These results raise a public health concern regarding the consequences of arbovirus outbreaks happening in areas with droughts and/or frequent freshwater cyanobacterial blooms.

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Cyanobacterial occurrence and detection of microcystins and saxitoxins in reservoirs of the Brazilian semi-arid

Cited by 31 publications

References 64 publications

Phytoplankton scenario and microcystin in water during extreme drought in semiarid tropical water supplies, Northeastern Brazil

Phytoplankton scenario and microcystin in water during extreme drought in semiarid tropical water supplies, Northeastern Brazil

Cyanobacterial blooms in freshwaters bodies in a semiarid region, northeastern Brazil: A review

The cyanobacterial saxitoxin exacerbates neural cell death and brain malformations induced by Zika virus

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