Can small-bodied Daphnia control Raphidiopsis raciborskii in eutrophic tropical lakes? A mesocosm experiment
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RESEARCH ARTICLE
Can small-bodied Daphnia control Raphidiopsis raciborskii in eutrophic tropical lakes? A mesocosm experiment Aloysio S. Ferrão-Filho 1
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& Uanderson J. Pereira & Mauro C.P. Vilar & Leonardo de Magalhães & Marcelo M. Marinho
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Received: 1 November 2019 / Accepted: 15 June 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Raphidiopsis raciborskii is being considered an expanding, invasive species all over the world. It is a potentially toxin producer cyanobacterium and form blooms specially in (sub)tropical lakes, causing concern to public health. Thus, controlling such phenomena are of vital importance. To test the hypothesis that a tropical clone of Daphnia laevis is able to reduce the biomass of R. raciborskii, we performed a mesocosm experiment simulating a bloom of this cyanobacterium in field conditions and exposing it to ecologically relevant densities of daphniids. In addition, we tested the hypothesis that omnivorous fish would be able to exert a top-down effect on Daphnia, decreasing the effectiveness of this control. We used treatments with (10 and 20 Daphnia L-1) or without Daphnia and fish (3 per mesocosm). Daphnia was able to significantly reduce the biomass of R. raciborskii only at the highest density tested. Fish had low effect on Daphnia biomass, but it is suggested that nutrient recycling by fish might have contributed to the higher R. raciborskii biomass in fish treatments. This is the first evidence of Daphnia control over saxitoxin-producing cyanobacteria in a tropical ecosystem. Keywords Cyanobacteria . Zooplankton . Toxins . Top-down control . Biomanipulation
Introduction Cyanobacterial blooms have been a matter of concern worldwide as they can cause harmful effects to animals and humans (Azevedo et al. 2002; Ferrão-Filho and Kozlowsky-Suzuki 2011). These organisms produce a series of metabolites with
toxic properties, among the most known are hepatotoxins (microcystins and nodularin), neurotoxins (anatoxins, saxitoxins, and the amino acid β-methylamino-L-alanine— BMAA), cytotoxins (cylindrospermopsins), dermatotoxins (aplysiatoxins and lyngbyatoxins), and skin-irritant extra-cellular lipopolysaccharides (Chorus and Bartram 1999; Buratti
Responsible Editor: Vitor Manuel Oliveira Vasconcelos Highlights Effects of Daphnia laevis and fish on cyanobacterial biomass were tested in mesocosms. Daphnia significantly reduced the biomass of R. raciborskii only at 20 individuals/L. Fish had low effect on Daphnia biomass and likely affected cyanobacteria by N/P. This is the first evidence of Daphnia control over saxitoxin-producing cyanobacteria. * Aloysio S. Ferrão-Filho [email protected] Uanderson J. Pereira [email protected] Mauro C.P. Vilar [email protected] Leonardo de Magalhães [email protected] Marcelo M. Marinho [email protected]
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Laboratory of Evaluation and Promotion of Environmental Health, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ 21040-360, Brazil
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Postgraduate Program in Biological Sciences, Departme
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