Banca de DEFESA: RAFAEL CORRÊA MUNIZ

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RAFAEL CORRÊA MUNIZ
DATE: 05/08/2022
TIME: 09:00
LOCAL: Auditório NTB - Campus Tapajós
TITLE:

INTRA AND INTER-ANNUAL VARIATION OF DISSOLVED CATIONS AND TRACE ELEMENTS IN THE MAIN CHANNEL OF THE AMAZONAS RIVER, ÓBIDOS-PARÁ

KEY WORDS:

Cations. Elements Traces. Amazon river. Seasonality.

PAGES: 48
BIG AREA: Outra
AREA: Ciências Ambientais
SUMMARY:

The current work studies the concentrations and variations of cations (Na+, Mg2+, K+, Ca2+) and trace elements (Li+, Sr2+, Rb+, Ba2+, U) in the waters of the Amazon river, near the city of Óbidos during the years 2012 and. 2013. The sample point covers 69% of the entire basin, about 4.67 million km2 upstream. For cover all the heterogeneity of the river and its tributaries, the samples were collected in a transect of the river, in 3 different points and equally spaced at a depth of 0.5 meters. Sample analyzes were made at the WoodWell Climate Research Institute, using Plasma-Source Mass Spectrometry (ICP-MS). The results showed that during the study period there was an abundance of Ca2+ cation following an order of predominance Ca2+>Na+>Mg2+>K+. All concentrations of cations changed according to the flood pulse of the river presenting, in most cases, peaks of concentrations in the rising periods and lower values for the lowing period of the river. This hysteresis effect can be explained by the different contributions of other ion sources to the rivers. Most of the trace elements followed the trend of the cations, presenting their highest and lowest values in the transitional period of the river, between the flood and dry. Their order of dominance was for Sr2+> Ba2+> Li+> Rb+>U. The hydrograph phases (Rising, Flood, Lowing, Dry) showed significant differences for the concentrations of the compounds studied, showing that there is intra-annual variation in the concentrations of the compounds in the river, but the same result was not significant for the variation between the years of study kepping an interannual concentration stability. Therefore, the seasonality present in the Amazon river changes the concentration of compounds, making it important to understand the dynamics of these ions and model the flow of these elements to the river.

BANKING MEMBERS:
Externa ao Programa - 2386579 - DIANI FERNANDA DA SILVA LESS
Presidente - 1794276 - JOSE MAURO SOUSA DE MOURA
Externo ao Programa - 2195729 - RAONI AQUINO SILVA DE SANTANA
Interno - 1549120 - RODRIGO DA SILVA