Influence of environmental variables on saxitoxin yields by Cylindrospermopsis raciborskii in a mesotrophic subtropical reservoir

Autor(es)

Casali, Simone Pereira ; Alves Dos Santos, Andre Cordeiro ; de Falco, Patricia Bortoletto ; Calijuri, Maria do Carmo

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF WATER AND HEALTH; v. 15, n. 4, p. 509-518, AUG 2017.
• Citações Web of Science: 3

Resumo

Saxitoxins are a class of toxins produced by at least two groups of evolutionarily distant organisms (cyanobacteria and dinoflagellates). While the toxicity of these toxins is relatively well characterized, to date little is known about their drivers and ecological functions, especially in lower latitude tropical and subtropical freshwater ecosystems. In the present study, we aimed to obtain a better understanding of the main drivers of saxitoxin concentrations in aquatic environments. We investigated the relationships among saxitoxin concentrations in a mesotrophic subtropical reservoir dominated by the cyanobacteria Cylindrospermopsis raciborskii with physical, chemical and biological water variables. The highest saxitoxin concentrations were 0.20 mu g.L-1, which occurred in the samples with the highest densities of C. raciborskii (maximum of 4.3 x 10(4) org.mL(-1)) and the highest concentration of dissolved nutrients (nitrate from 0.2 to 0.8 mu g.L-1, ortophosphate from 0.3 to 8.5 mu g.L-1). These correlations were confirmed by statistical analyses. However, the highest saxitoxin relative concentrations (per trichome) were associated with lower C. raciborskii densities, suggesting that saxitoxin production or the selection of saxitoxin-producing strains was associated with the adaptation of this species to conditions of stress. Our results indicate that C. raciborskii toxin yields vary depending on the enrichment conditions having potential implications for reservoir management. (AU)

• Processo FAPESP: 08/55636-9 - Contribuição ao conhecimento do ciclo do carbono no reservatório de Itupararanga como subsídio para a sustentabilidade da Bacia Hidrográfica do Rio Sorocaba (SP)
• Beneficiário: Maria do Carmo Calijuri
• Modalidade de apoio: Auxílio à Pesquisa - Temático