Banca de DEFESA: MARIA APARECIDA PEREIRA SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : MARIA APARECIDA PEREIRA SANTOS
DATA : 08/09/2021
HORA: 14:30
LOCAL: PLATAFORMA VIRTUAL GOOGLE MEAT
TÍTULO:

NUTRIENT TRANSFER PROCESSES AT INTERFACECONTINENT-OCEAN IN THE DELTA OF THE RIVER PARNAÍBA

PALAVRAS-CHAVES:

Estuaries, nutrients, Eulerian and Lagrangian approach.

PÁGINAS: 64
GRANDE ÁREA: Outra
ÁREA: Ciências Ambientais
RESUMO:

Estuaries can be described as biogeochemical hotspots with high rates of primary productivity. Because these are open systems, there is a constant flow of matter and energy, responsible for a range of physical, chemical and biological, essential for the maintenance and balance of the environment. This study aimed estimate the fluxes of nutrients, Total Nitrogen (NT) and Total Phosphorus (PT) at the interface continent-ocean in the Parnaíba River Delta, in addition to evaluating the temporal distribution (Eulerian approach) and spatial (Lagrangian approach) of the parameters hydrochemicals (pH, temperature, dissolved oxygen (DO), turbidity, salinity, in function of ecosystem conditions (tide and flow), in order to examine the behavior of these compounds and the main interactions pertinent to these systems. For this, 1 (one) sampling campaign on surface and bottom was carried out, contemplating flood and ebb tide in the main channel of the estuary in September of 2019, corresponding to the quadrature tide. The physicochemical parameters were measured in situ with portable multiprobe and nutrient fractions (NT and PT) followed the procedures proposed by Valderrama (1981). Data resulting from the approach lagrangiana were evaluated to determine the distribution as a function of the tides. (Ebb and Flood), submitted to Principal Component Analysis (PCA) in the Past program (version 4.03) and analyzed for N:P ratio. Eulerian measurements in the estuary were carried out in order to cover the temporal variability of the area of study to estimate the inflow and outflow of nutrients. The patterns of behavior of the parameters as a function of the tide showed similarities, with few variations. The PCA evidenced that the NT, turbidity and PT elements are positively correlated with each other, which means that water samples with high nutrient concentration tend to also have high concentrations of turbidity. From the perspective of limiting nutrients, N:P ratio, it was observed that 62.5% of the analyzed samples had NT as a limiting factor. In the results of Eulerian approach, considering the net balance resulting from the total retained and total exported to NT and PT, it was estimated that the outflow of NT retained 20.43 ton. day and total exported 12.75 ton.day, so the outflow was lower 7.68 ton.day, checking to the estuary the characteristic of a total nitrogen retainer. The retained PT was 0.19 ton.day and exported 1.07 ton.day, estimating that the estuary behaves as an exporter of total phosphorus. Nutrients compared to tides showed values maximum NT and PT 7.42 μmol/ and 1.08 μmol/L respectively, corroborating with similar studies of Brazilian estuaries. And overall, these results provide improved insights into hydrochemical flows and patterns in the estuary, which expects them to be useful for programs to monitor and manage these systems.

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