Banca de QUALIFICAÇÃO: NATALIANA DA SILVA SOUZA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : NATALIANA DA SILVA SOUZA
DATE: 05/04/2021
TIME: 14:00
LOCAL: Videoconferência
TITLE:

Bacterial community and maintenance of soil quality in relatively pristine and anthropogenically-influenced mangrove ecosystems in the Northeast of Brazil

KEY WORDS:

Organic matter; Nutrients; Bacterial diversity; 16S rRNA; Soil enzymes; Microbial biomass

PAGES: 34
BIG AREA: Ciências Biológicas
AREA: Botânica
SUBÁREA: Fisiologia Vegetal
SUMMARY:

Mangroves are highly productive and dynamic coastal ecosystems that have a high diversity of microorganisms, which play key roles in maintaining productivity and soil quality. As a result, several characteristics of the biological component of the soil, such as microbial biomass, metabolic activity, presence of thermotolerant coliforms, and the microbial community can be used as bioindicators to assess environmental changes. This study aimed to evaluate the possible environmental status of two mangroves using soil bioindicators, characterization of bacterial communities in the bulk soil and rhizosphere of Laguncularia racemosa, and their potential metabolic functions for the ecosystem using a culture-independent approach. Tatuamunha (relatively preserved) and Santo Antônio (impacted by shrimp farming) are located in the north of the state of Alagoas, in northeastern Brazil. In each area, three sample points were established along the river with a distance of 1.5 km from each other. In each point, soil and water were collected for analysis of thermotolerant coliforms, enzymatic activity, microbial biomass and 16S rRNA gene amplicon based metagenomic. The sequencing of the samples resulted in 19,425 ASVs and 768,828 sequences of the high-quality 16S rRNA gene. Organisms belonging to 49 phyla, 119 classes, and 354 families were identified. The eleven most abundant phyla were Proteobacteria, Desulfobacterota, Bacteroidota, Chloroflexi, Acidobacteriota, Campilobacterota, Verrucomicrobiota, Planctomycetota, Nitrospirota, Myxococcota, and the candidate group MBNT15. The Shannon index did not differ between the conditions evaluated, however, the analysis of an NMDS showed a slight separation of the two mangroves and a considerable separation of the sampling points. The increased activity of β-glucosidase and the low C: N-SMB ratio in Santo Antônio suggest higher rates of decomposition of organic matter in sediments. The functional prediction using FAPROTAX demonstrated that the bacteria from Santo Antônio mangrove had a greater association with methane metabolism for energy, while the functional groups in Tatuamunha indicate higher photosynthetic rates in the sediments of this mangrove. The natural variation of physicochemical conditions along the rivers has also been shown to have the capacity to influence the dominant processes by inhibiting taxa related to nitrogen metabolism and stimulating groups that metabolize methane. Our results showed the existence of homogeneous bacterial communities in both mangroves, with bacteria presenting natural variations due to the physical and chemical conditions of the rivers.

BANKING MEMBERS:
Interna - 1861153 - PATRICIA MUNIZ DE MEDEIROS
Interna - 2024367 - MELISSA FONTES LANDELL
Interno - 1916144 - GILBERTO COSTA JUSTINO
Externa à Instituição - LILIANE SANTOS DE CAMARGOS - UNESP
Externo à Instituição - FERNANDO DINI ANDREOTE - USP