Resposta isotópica em Siderastrea stellata à variabilidade climática no Atol das Rocas - RN, Brasil

• Ano de defesa: 2020
• Autor(a) principal: Agostinho, Paula Gabriela Fernandes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Rio Grande do Norte; Brasil; UFRN; PROGRAMA DE PÓS-GRADUAÇÃO EM CIÊNCIAS CLIMÁTICAS
• Palavras-chave em Português: Caracterização climática; Geoquímica de Coral; Ciclos Isotópicos; Paleotermômetro
• Link de acesso: https://repositorio.ufrn.br/handle/123456789/31397

In the current climate scenario, the need to provide accurate projections of future weather and climate evolution, demand for long-term historical environmental data. The historical record of climate events in Brazil is relatively short, rarely exceeding 100 years in duration, mainly with respect to data from oceanic regions. In many oceanic regions of the tropical zone, corals contribute to fill this lack of instrumental data, however, in Brazil, research based on endemic corals is limited. In this context, the objective of this research was to contribute to the validation of geochemical data obtained in the coral skeleton Siderastrea stellata as paleoclimatic indicators for the Rocas Atoll. This biological reserve has no climatic monitoring, and here, in a pioneering study, the characterization of the climatological behavior of the Sea Surface Temperature (SST) and Precipitation for 55 years of data was developed, in association with the variations caused by the influence of the main oceanic-atmospheric systems and phenomena responsible for the climatic variability of the Northeast of Brazil: the Intertropical Convergence Zone, the Interhemispheric Thermal Gradient, and El Niño – Southern Oscillation. After this initial study, changes in the stable Carbon Isotopes (δ13C), stable Oxygen Isotopes (δ18O) and Strontium/Calcium ratios (Sr/Ca) in response to the heating and precipitation caused by the aforementioned modes of variability were investigated. The comparison of geochemical data with environmental data, showed that the species Siderastrea stellata has a great potential to be used in paleoclimatic studies, mainly in those related to SST.