Navegando por Assunto "Antropoceno e Holoceno"

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A aplicação da cromatografia gasosa acoplada (GC-FID), isótopos estáveis, palinologia e razão C:N na reconstituição paleoambiental de manguezais do Estado da Bahia e Espírito Santo.
(Universidade Federal do Pará, 2024-07-30) SILVA, Fernando Augusto Borges da; ALBERGARIA-BARBOSA, Ana Cecília Rizzatti de; http://lattes.cnpq.br/2666263256585897; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790; https://orcid.org/0000-0002-3784-7702
Mangroves depend on ideal geomorphological, geochemical, and climatic factors to develop. Brazil, with its highly indented coastline under tropical and sub-tropical climate regimes, presents suitable conditions for the establishment of these ecosystems and distribution. The dynamics of these mangroves can be influenced by factors related to climatic variations and changes in hydrodynamic flow, resulting in modifications in sediment input and the origin of organic matter. These changes can be observed throughout the Holocene in different regions in of the country. On the northeast and southeast coast, the evolution of these ecosystems is associated with fluctuations in relative sea level (RSL) and sedimentary dynamics, while in the southern region, the change in the distribution of mangroves is a reflection of fluctuations in the RSL and climate changes caused by warming global. Recent studies seek to describe the evolution of these environments based on the elemental and isotopic characterization of organic matter. These constitute important tools in paleoenvironmental reconstruction. However, it is necessary to remember that the comparative analysis of the largest possible number of independent parameters is relevant as it adds value to the research and increases the reliability of the data to be analyzed, generating more precise information. Therefore, aiming to unravel the dynamics of organic matter in mangrove environments, as well as understanding movements of expansion and/or contraction of these ecosystems, analyzes of nalkanes were carried out using chromatography (GC-FID), associated with the sedimentary study, pollen data, isotopic and elemental analyses, synchronized with 14C and 210Pb dating, which allowed obtaining information about past biogeochemical processes and environmental changes during the Holocene and Anthropocene in the coastal plain at the mouth of the Itapicuru river (BA) and at the mouth of the Barra Seca and Jucu rivers (ES). Thus, the results of this research are presented in five scientific articles. The first, see chapter III, deals with the expansion of mangroves at the mouth of the Itapecuru river (BA) during the Anthropocene. The second scientific article (chapter IV) deals with the dynamics of mangroves at the mouth of the Barra Seca River, on the northern littoral of the State of Espírito Santo. The third article (chapter V) discusses the palynology tool used to understand the dynamics of coastal vegetation.The fourth article (chapter VI) presents the environmental changes that occurred at the mouth of the Jucu River, on the central coast of the State of Espírito Santo. Finally, the fifth article presents the results of n-alkanes analyses, compared with isotopic, elemental, palynological data, and 14C dating on the coastal plain of the Barra Seca River.