TY - JOUR AU - Souza, Vitor Ricardo de AU - Alves Amorim, Cihelio AU - do Nascimento Moura, Ariadne PY - 2021/10/26 Y2 - 2024/03/28 TI - Effects of a submerged macrophyte, Ceratophyllum demersum (Ceratophyllaceae) and a cladoceran, Moina micrura (Cladocera: Moinidae) on microalgal interactions JF - Revista de Biología Tropical JA - Rev. Biol. Trop. VL - 69 IS - 4 SE - Articles DO - 10.15517/rbt.v69i4.42589 UR - https://revistas.ucr.ac.cr/index.php/rbt/article/view/42589 SP - 1276–1288 AB - <p><strong>Introduction: </strong>Cyanobacterial blooms in tropical water bodies are increasingly common, because of eutrophication and rising temperatures. Consequently, many freshwater systems are affected, by reducing water quality, biodiversity, and ecosystem services. With the increased frequency of harmful algal blooms, the development of biological tools to improve water quality is an urgent issue. <strong>Objective:</strong>&nbsp;To evaluate the effects of a submerged macrophyte and a cladoceran on the microcystin-producing cyanobacteria <em>Microcystis aeruginosa </em>(NPLJ-4) and the chlorophyte <em>Raphidocelis subcapitata</em>&nbsp;(BMIUFRPE-02) in mixed cultures. <strong>Methods: </strong>Two parallel experiments were carried out for ten days to evaluate the effects of the submerged macrophyte <em>Ceratophyllum demersum </em>and the cladoceran <em>Moina micrura</em>&nbsp;on microalgal interactions. Microalgal strains were cultivated in the ASM1 culture medium, under controlled laboratory conditions. The first experiment presented four treatments: M (<em>C. demersum</em>), Z (<em>M. micrura</em>), MZ (<em>C. demersum</em>&nbsp;and <em>M. micrura</em>), and C (control). Meanwhile, the second experiment consisted of five treatments, in which the microalgae were cultivated together at different <em>Microcystis</em>:<em>Raphidocelis</em>&nbsp;ratios: 1:0, 3:1, 1:1, 1:3, and 0:1. Biomass and growth rates of the strains were evaluated every two days, which were statistically treated with three-way or two-way repeated-measures ANOVA. <strong>Results: </strong>In the first experiment, <em>M. aeruginosa </em>was significantly inhibited in M and MZ<em>&nbsp;</em>treatments from the second day, and Z from the fourth, while<em>&nbsp;R. subcapitata </em>showed no reduction in its biomass in any treatment. On the other hand, <em>R. subcapitata </em>was stimulated from the eighth and tenth days in M treatment and only on the eighth day in Z treatment. In the second experiment,<em>&nbsp;M. aeruginosa</em>&nbsp;was significantly inhibited when cultivated with <em>R. subcapitata</em>&nbsp;in low ratios (<em>Microcystis</em>:<em>Raphidocelis</em>&nbsp;ratio of 1:3) throughout the experiment, while the chlorophyte was stimulated in that treatment. <strong>Conclusions: </strong>The coexistence of a cyanobacterium with a green alga did not alter the main negative response of <em>M. aeruginosa </em>to the submerged macrophyte and zooplankton but stimulated the green alga. Accordingly, the introduction of submerged macrophytes and cladocerans already adapted to eutrophic conditions, both isolated and combined, proved to be a good method to control cyanobacterial blooms without negatively affecting other coexisting phytoplankton species.</p> ER -