Banca de DEFESA: BRENDA LORENA SOARES DA SILVA BRAGA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : BRENDA LORENA SOARES DA SILVA BRAGA
DATA : 19/07/2019
HORA: 09:00
LOCAL: Sala 104C - IGeo
TÍTULO:

δ13C DE CORAIS ESCLERACTÍNEOS UMA FERRAMENTA NA QUANTIFICAÇÃO DE 12CO2 ABSORVIDO PELO OCEANO SUPERFICIAL ATLÂNTICO SUL EQUATORIAL

PALAVRAS-CHAVES:

Paleoclimatology. Isotopic geochemistry. Anthropogenic CO2. Reef environments

PÁGINAS: 60
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Geologia
RESUMO:

The growing interest in palaeoclimatic reconstructions has promoted a quick advancement in studies that use geochemical records from natural archives (e.g. tree rings, ice cores, corals) to access past environmental conditions. Among these, the coral-based records stand out as an important tool in understanding climate variability in the tropics. During the precipitation of the exoskeleton of corals from sea water, isotope ratios and trace elements (e.g. δ18O, δ13C and Sr/Ca) are incorporated in this structure. The isotopic composition of coral skeleton (δ18O and δ13C) have often been used as an indicator in the estimate of various environmental factors (e.g. temperature, solar radiation, cloud cover, turbidity, dissolved inorganic carbon). The oxygen isotope has been used in the reconstruction of past temperature and carbon isotope has been used to estimate changes in the isotopic composition of dissolved inorganic carbon in the oceans because of changes in δ13C-CID related to increase of 12C derived from burning of fossil fuels known as the Suess Effect. Here we report the δ18O and δ13C isotopic data based in colonies of the species Mussismilia braziliensis and Siderastrea stellata, to the South Atlantic Ocean. Isotope cycles indicate ages of 15, 23 and 27 for colonies of M. braziliensis and 22, 32 and 41 for colonies of S. stellata. The average values of carbon and oxygen isotope were respectively of 0.13 ± 0.99 and 2,19 ± 0.23‰ (SS01G),-1,69 ± 0.55 e-2,39 ± 0.98‰ (SS02D), 0.22 ± 0.46‰ e-2,24 ± 0.33‰ (SS03D) and -0.71 ± 0.74 and-3 ± 1.21‰ (MB01_2C),-0.58 ± 3,09 e-2,67 ± 0.08‰ (MB02D),-1.44 ± 0.11 and-2.70 ± 1.28‰ (MB03B). Data from the SOI (Southern Oscillation Index) were used and compared with the oxygen isotope records. The species S. stellata exhibited a negative trend in the δ13C temporal series of the three colonies, similar to the impoverishment observed in other regions of the South Atlantic. The δ13C of the colonies of M. braziliensis presented short-term variation mainly related to physiology. Isotopic carbon record based on corals of the species S. stellata is an important tool to tell how the isotope change that has been occurring in CO2 from the Equatorial South Atlantic Ocean. The isotopic content of the species M. braziliensis needs to be better explored.

MEMBROS DA BANCA:
Externo à Instituição - BÁRBARA PINHEIRO RAMOS - UFBA
Externo ao Programa - 2349838 - MARIA DO ROSARIO ZUCCHI
Presidente - 1348177 - RUY KENJI PAPA DE KIKUCHI