Phytoplankton composition and metabolomic profiles in aquaculture systems: A case study in Brazil's natural lakes

Author(s)

Almeida, Eryka Costa ; Jacinavicius, Fernanda Rios ; Passos, Larissa Souza ; Medice, Rhuana Valdetario ; Marques, Lucas Gregorio ; Crnkovic, Camila Manoel ; Marinho, Marcelo Manzi ; Gomes, Levy de Carvalho ; Pinto, Ernani

• Document type: Journal article
• Source: Aquaculture; v. 599, p. 13-pg., 2025-01-17.

Abstract

Cyanobacteria are highly adaptable organisms that produce a wide range of secondary metabolites, many of which remain poorly understood. This study explores the cyanobacterial communities and their metabolomic profiles in Palmas and Palminhas Lakes, two of Brazil's deepest natural lakes, focusing on the impacts of tilapia aquaculture. Using liquid chromatography coupled with mass spectrometry (LC-MS) and phytoplankton assessments, areas with and without floating cage fish farms were compared. Cyanobacteria dominated the phytoplankton, with Raphidiopsis raciborskii (61.04 % of total cell count) being the most abundant species, followed by Aphanocapsa incerta (24.58 %) and others. Both R. raciborskii and A. incerta exceeded Brazil's regulatory density limit of 2.0 x 104 cells mL-1, raising concerns about risks to aquatic life and public health. R. raciborskii is particularly concerning due to its potential to produce toxins like saxitoxin and cylindrospermopsin. Although traditional cyanotoxins were not detected at the time of sampling, several metabolites were identified, including the cyanopeptide namalide B and other compounds with biological activities. Increased ammonia levels and nutrient dynamics suggest that aquaculture is subtly altering the lakes' chemical and biological compositions, posing risks to ecosystems and public health even without detectable cyanotoxins. The findings emphasize the need for ongoing monitoring of cyanobacterial metabolites beyond traditional cyanotoxins and water quality in aquaculture systems to mitigate ecological and health risks. (AU)

• FAPESP's process: 22/02872-4 - Integrated strategies for natural product discovery from Brazilian cyanobacteria
• Grantee: Camila Manoel Crnkovic
• Support Opportunities: Research Grants - Initial Project
• FAPESP's process: 21/14239-1 - Effects of interaction between synthetic and natural organophosphates on Oreochromis niloticus (Teleostei: Cichlidae)
• Grantee: Larissa Souza Passos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 24/02448-3 - Analysis of the impact of cyanobacteria inoculation on the maize rhizosphere community
• Grantee: Fernanda Rios Jacinavicius
• Support Opportunities: Scholarships in Brazil - Technical Training Program - Technical Training
• FAPESP's process: 13/07914-8 - FoRC - Food Research Center
• Grantee: Bernadette Dora Gombossy de Melo Franco
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 21/00149-0 - Treatment and selective fractionation of cyanobacteria in blooms for the production of value-added supplies
• Grantee: Ernani Pinto Junior
• Support Opportunities: Regular Research Grants