Phytoplankton composition and metabolomic profiles in aquaculture systems: A case study in Brazil's natural lakes
Article
Almeida, ÉC, Jacinavicius, FR, Passos, LS et al. (2025). Phytoplankton composition and metabolomic profiles in aquaculture systems: A case study in Brazil's natural lakes
. AQUACULTURE, 599 10.1016/j.aquaculture.2025.742135
Almeida, ÉC, Jacinavicius, FR, Passos, LS et al. (2025). Phytoplankton composition and metabolomic profiles in aquaculture systems: A case study in Brazil's natural lakes
. AQUACULTURE, 599 10.1016/j.aquaculture.2025.742135
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 × 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.
