Banca de DEFESA: ALANA JADE DE LIMA BEZERRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ALANA JADE DE LIMA BEZERRA
DATA : 13/04/2018
HORA: 14:30
LOCAL: Sala 212 do CTEC (Auditório do CCEA)
TÍTULO:

PHOSPHORUS RELEASE FROM SEDIMENTS AND THE ROLE OF OXYGEN AND TROPHIC STATE

PALAVRAS-CHAVES:

Sediment-water interface. Phosphorus release. Eutrophication. Internal loading.

PÁGINAS: 30
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Sanitária
RESUMO:

Phosphorous (P) is a limiting nutrient of algal growth. Reducing input of point P sources of surface waters, although essential, is not enough towards mitigating eutrophication due to the P internal loading. There are numerous factors that can interfere on P release characteristics, those includes oxygen presence and trophic state of overlying water. Hence, our study intended to analyze P fluxes concerning the oxygen presence and the phosphorus concentrations of overlying water utilizing several microcosms in order to simulate the proposed conditions. Overall, P fluxes were higher when a low P concentration overlying water situation was simulated under hypoxic conditions for both SRP and DOP fluxes. With natural overlying water, P release was greater also under hypoxic conditions, which is an indicative of higher inorganic P bonded to FeOOH. When the P fluxes are analyzed temporally, we could notice that P fluxes were positive at the first seven days, then, mostly negative for the rest of the experiment. This indicates that, although P release is significant throughout the experiment, phosphorus behavior is dynamic in time. SRP fluxes for the 0-7 day interval showed interaction only with variation of P concentration in overlying water, while DOP fluxes exhibit only interaction with both O2 and P concentrations. The 7-14 day interval indicates higher phosphorus retention in oxic conditions for both SRP and DOP fluxes. SRP fluxes were significantly changed with oxygen conditions, while DOP fluxes, with P concentration. Both SRP and DOP fluxes showed interaction between categorical factors. Thus, in semiarid regions such as Gargalheiras’, P release might continue being a serious problem due to its high temperature and pH, low depth and elevated evaporation rates, which contributes to concentrate P in overlying water and induce anoxic conditions in sediment. Also, even if the the rainy season come to dilute P in water, P release may be favored owing to P gradient concentration due to the large P pool in sediments.

MEMBROS DA BANCA:
Presidente - 052.716.174-83 - FABIANA OLIVEIRA DE ARAUJO SILVA - UFRN
Interno - 1362202 - JOSE LUIZ DE ATTAYDE
Interno - 1764855 - VANESSA BECKER
Externo à Instituição - NATÁLIA PESSOA NOYMA - UERJ