Banca de QUALIFICAÇÃO: MARIA APARECIDA PEREIRA SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : MARIA APARECIDA PEREIRA SANTOS
DATA : 05/05/2021
HORA: 09:00
LOCAL: PLATAFORMA GOOGLE MEET
TÍTULO:

DYNAMICS OF HYDROCHEMICAL PARAMETERS IN THE CONTINENT-OCEAN INTERFACE
IN THE DELTA DO RIO PARNAÍBA REGION

PALAVRAS-CHAVES:

Estuaries, nutrients, Eulerian and Lagrangian approaches.

 

PÁGINAS: 55
GRANDE ÁREA: Outra
ÁREA: Ciências Ambientais
RESUMO:

Estuarine ecosystems are open systems, in which there is a constant flow of matter and energy, responsible for a range of physical, chemical and biological processes that are essential for the maintenance and balance of the environment. This study aimed to analyze the distribution (temporal and spatial) of the hydrochemical parameters (pH, temperature, dissolved oxygen (OD), turbidity, salinity, total nitrogen (NT) and total phosphorus (PT) in the estuarine zone of the Parnaíba Delta in function of the dynamics of the ecosystem, in order to examine the behavior of these compounds and the main interactions pertinent to these systems. For this, 1 (one) surface and bottom sampling campaign was carried out, contemplating flood and ebb tide in the main channel of the estuary (Rio Parnaíba), in September 2019, corresponding to the quadrature tide. The physical-chemical parameters were measured in situ with a portable multisort and the nutrient fractions (NT and PT) followed the procedures proposed by Valderrama, 1981. The data were subjected to statistical analysis in the Past program (version 4.03) for the elaboration of the graphs , descriptive statistics and statistical tests. Initially, the Shapiro - Wilk normality test was applied, with 95% confidence, for the variables in each approach (Eulerian and Lagrangian), and later to identify the most important variables in determining the variability of the data obtained, an Analysis of Main Components (ACP). The hydrochemical parameters were found to be similar for the two tide regimes analyzed. The nutrients compared to the tides, showed maximum values of NT and PT 7.42 µmol / and 1.08 (µmol / L) respectively, corroborating with similar studies of Brazilian estuaries. From the perspective of limiting nutrients, N: P ratio, considering the points from P1 to P6, it was observed that 57.69% of the analyzed samples had NT as a limiting factor. In the temporal approach, considering points P2 and P5, it presented values of 63.63% and 59.72%, respectively. This behavior demonstrates that, in general, the limiting element for the analyzed area would be the NT. The results of the ACP demonstrated that the Parameters behaved differently in the two approaches, in the Langrangean approach it was found that the elements NT, turbidity and PT are positively correlated with each other, which means that water samples with a high concentration of nutrients, tend to also present high concentrations of turbidity. For the Eulerian approach at P2, it is clear that turbidity, NT, and PT have a negative relationship with OD and pH and salinity negatively opposes temperature. In P5, a negative correlation was observed between the parameters turbidity, NT and OD, implying that higher concentrations of turbidity result in lower concentrations of NT and OD. These behavioral patterns will guide and support the assessment of nutrient input at the estuary's continent-ocean interface.

 

MEMBROS DA BANCA:
Presidente - 1239724 - ANA CELIA MAIA MEIRELES
Interno - 1513585 - FRANCISCO JOSE DE PAULA FILHO
Externo à Instituição - JOSÉ RIBEIRO DE ARAÚJO NETO - IFCE
Externo à Instituição - TEOBALDO GABRIEL DE SOUZA JÚNIOR - IFPB