Banca de DEFESA: NATALIANA DA SILVA SOUZA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : NATALIANA DA SILVA SOUZA
DATE: 24/08/2021
TIME: 14:00
LOCAL: Videoconferência - Google meet
TITLE:

Bacterial community and accumulation of nutrients and heavy metals in mangrove sediments from the North Coast of Alagoas State

KEY WORDS:

Bioindicators, chemical composition, microbiota, environmental quality, productivity

PAGES: 60
BIG AREA: Ciências Biológicas
AREA: Botânica
SUBÁREA: Fisiologia Vegetal
SUMMARY:

Mangroves are ecosystems with high productivity and diversity of microorganisms, which are essential factors for maintaining the environmental quality of these ecosystems. Several characteristics of the soil biological component, such as microbial biomass, metabolic activity, presence of thermotolerant coliforms, and the microbial community are good bioindicators to assess environmental changes. Thus, this study aimed to evaluate the quality of the soil from two mangroves in Northeastern Brazil with different preservation histories, Tatuamunha (relatively preserved) and Santo Antônio (impacted by human action). In each area, three points were sampled, where water and soil samples were collected and used to quantify total and thermotolerant coliforms, nutritional composition, enzyme activity, microbial biomass, and DNA extraction from the sediment. As for their chemical compositions, Tatuamunha had a higher accumulation of K, S, Fe, Na, Ni, and Cr while Santo Antônio accumulated higher amounts of P, Cu, and Pb. High coliform counts indicated the presence of fecal contamination in both environments, mainly in Santo Antônio. The high enzymatic activity is an evidence of high rates of nutrient mineralization in the sediments, especially for Santo Antônio. Santo Antônio had higher β-glucosidase activity, which may suggest a greater input of organic matter into this mangrove swamp. Organisms belonging to 49 phyla, 119 classes, and 354 families were identified from the sequencing of 16S rRNA gene amplicons. The eleven most abundant phyla were Proteobacteria, Desulfobacterota, Bacteroidota, Chloroflexi, Acidobacteriota, Campylobacterota, Verrucomicrobiota, Planctomycetota, Nitrospirota, Myxococcota, and the candidate group MBNT15. Shannon’s and observed diversity indices did not vary between mangroves, however, a NMDS analysis showed a slight separation in the bacterial communities of the two mangroves. Among the nutrients assessed, P accumulation was the most important factor to shape the bacterial community of Santo Antônio, while Tatuamunha was more influenced by the accumulation of other elements such as Na, Cr, Ni, and Fe. Functional prediction by FAPROTAX showed that the bacteria from the Santo Antônio mangrove had a greater association with the metabolism of methane to obtain energy, while the functional groups in Tatuamunha indicate higher photosynthetic rates. Among the sampling points, Tatuamunha had a greater variation of taxonomic groups, well above Santo Antônio. It shows that the bacterial community of Santo Antônio is more homogeneous and less affected by physicochemical variations along the river, probably due to greater environmental disturbance.

BANKING MEMBERS:
Externo à Instituição - FERNANDO DINI ANDREOTE - USP
Presidente - 1916144 - GILBERTO COSTA JUSTINO
Externo à Instituição - LUCAS ANJOS DE SOUZA - IF Goiano
Externo à Instituição - LUIZ FERNANDO WURDIG ROESCH - UFP