| Congresso Brasileiro de Microbiologia 2023 | Resumo: 667-1 | ||||
Resumo:Brazil's diverse marine ecosystems face threats from human-induced activities. While traditional assessment methods primarily concentrate on multicellular organisms, molecular methods are bringing microbial communities into the spotlight for environmental management. In this study, we compared the efficacy of metagenomics with classical ecological assessment methods. The research was conducted in the Marine Environmental Protection Areas of São Paulo. We collected sediment samples and documented both abiotic and biotic parameters in 29 sampling stations. The DNA extracted from these samples was sequenced and subsequently underwent bioinformatic analysis for taxonomic classification and functional comparison. We performed k-means clustering analysis for both abiotic and biotic metadata parameters. No discrepant area was identified using granulometry and ichthyofauna data. The areas of Queimada Grande Island (S59 and S61) and Bom Abrigo Island (S66) formed a cluster due to high carbonate content, while Castelhanos Island (S23), Búzios Island (S18), Baleia Island (S50), and Boiçucanga Rocky Shore (S40) clustered due to phosphorus and nitrogen levels. Toque-toque Island (S31) and Montão de Trigo Island (S52) were discrepant due to different heavy metals. Microbial community alpha diversity was measured based on the number of valid sequences, richness, rarefaction, and the indices of biodiversity, evenness, and inequality. Low richness numbers were noted for Castelhanos II (S22) and Itaçucê Island (S29) stations. However, S22 also displayed a low sequence number, with its discrepancy not persisting after richness normalization (rarefaction), indicating a sequencing artifact. S29, on the other hand, presented the lowest richness value tied to the highest sequence number, suggesting a consistent shift in the microbial community. This result was corroborated by the k- means analysis, which showed S29 as the only discrepant point in the study concerning microbial communities. Analysis of the most abundant taxa suggested an invasion in area S29, with organisms usually found abundant at other collection stations still present, but being superseded in numbers by four species from the Vibrionaceae family (including algae and sipunculid pathogens), along with Shewanella waksmanii, Alteromonas macleodii, Leisingera caerulea, and a Sandaracinaceae species. Functional profile analysis showed significantly increased genes related to iron transport, ribosome function, and glutamate metabolism in S29. We conclude that the sampling station at Itaçucê Island, at the time of sampling, was under the influence of a “Vibrio Bloom”, likely related to algae accumulation. These phenomena are generally routine and often dissipate naturally. The identification of this early sign, when no classic ecological assessment methods were able to do the same, demonstrates the sensitivity of microbial community-based analysis methods and highlights their promising application in environmental monitoring programs. Palavras-chave: Environmental Monitoring, Marine Ecosystems, Metagenomics, Microbial Communities, Vibrio Bloom Agência de fomento:Partnership: Petrobras - LNCC | |||||