Can the presence of green microalgae reverse the allelopathic effects of the submerged macrophyte Egeria densa on the toxin-producing cyanobacterium Raphidiopsis raciborskii?

• Published in: Hydrobiologia 2022-11, Vol.849 (19), p.4391-4406
• Main Authors: Barbosa, Vanessa Virginia, dos Santos Silva, Ranielle Daiana, dos Santos Severiano, Juliana, Chia, Mathias Ahii, de Lucena Barbosa, José Etham
• Format: Article
• Language: English
• Subjects: Algae; Allelopathy; Analysis; Aquatic microorganisms; Aquatic plants; Biomass; Biomedical and Life Sciences; Chlorella; Cyanobacteria; Ecology; Egeria densa; Experiments; Freshwater & Marine Ecology; Laboratories; Life Sciences; Macrophytes; Marine toxins; Microalgae; Phytoplankton; Plant extracts; Primary Research Paper; Raphidiopsis raciborskii; Saxitoxin; Toxins; Zoology
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-022-04997-4

Investigations on the influence of green microalgae associated with cyanobacteria exposure to macrophytes and the production of cyanotoxins have not been previously explored. The effects of the presence of live plants and extracts of the Egeria densa , on the growth and saxitoxin production of Raphidiopsis raciborskii were investigated in the presence and absence of Chlorella vulgaris . The physical presence of the macrophyte reduced the biovolume of the cyanobacterium and its production of saxitoxins, while cultures exposed to aqueous extract had elevated saxitoxin levels. The green microalgae also increased the amount of cyanotoxins, especially when the macrophyte biomass was low. These findings suggest that E. densa can inhibit the growth of R. raciborskii and the production of cyanotoxins and that the presence of C. vulgaris can alter these processes .