Banca de DEFESA: JUCIELIA TENORIO JUSTINO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JUCIELIA TENORIO JUSTINO
DATE: 05/09/2023
TIME: 14:00
LOCAL: Remoto através de plataforma google meet
TITLE:

Nematode assemblages as an indicator of ecological quality in river springs

KEY WORDS:

fresh water; agriculture; rural impact; meiofauna; functional diversity; body size

PAGES: 81
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUBÁREA: Ecologia Aplicada
SUMMARY:

Springs are important in supplying water systems, and are subject to various human impacts, such as deforestation of riparian forests, pollution and erosion of banks. Nematoda are excellent bioindicators of environmental disturbances given their high density, persistence in impacted environments and rapid responses to stressors. We investigated the taxonomic and functional structure of Nematoda assemblages and responses to environmental conditions, in springs with different agricultural activities: pasture and sugarcane cultivation, and in springs without influence of these activities, as controls. For taxonomic and functional diversity, the questions were investigated: Do springs located in areas where sugarcane cultivation and pasture activities are carried out, do they have low ecological quality? Can low ecological quality be perceived through changes in the structure of Nematoda assemblages? Hypotheses were also tested regarding Nematoda morphometry: I) the size distribution of freshwater Nematoda is similar to that proposed in the literature for marine and estuarine environments, II) this ratio responds to changes in physical-chemical characteristics of the environment, represented by headwaters of a river and III) this ratio differs between headwaters with and without the influence of agricultural activities. A total of 16 springs were analysed, water and sediment samples were collected and environmental parameters measured. Nematoda were identified in genera, and their body sizes were measured. In the water, Total Coliforms and Escherichia coli, and concentration of inorganic nutrients were measured. And in the sediment, chlorophyll-a concentrations, organic matter content, mercury concentration and granulometry. Springs without influence of activities showed better ecological status with greater abundance and richness of genera, greater trophic diversity and persistent Nematoda dominance, while springs with pastures and sugarcane showed an indication of impact. The length/width ratio of Nematoda presents a bimodal distribution, in different size ranges of marine environments. With differences in response to animal grazing activities and sugarcane cultivation, and to environmental variables, proving to be useful in assessing environmental quality in a freshwater environment.

COMMITTEE MEMBERS:
Presidente - 1544255 - TACIANA KRAMER DE OLIVEIRA PINTO
Interno(a) - 1278133 - GUILHERME RAMOS DEMETRIO FERREIRA
Externo(a) à Instituição - GIOVANNI AMADEU PAIVA DOS SANTOS - UFPE
Externo(a) à Instituição - RODOLFO LEANDRO DO NASCIMENTO SILVA