Please use this identifier to cite or link to this item: https://app.uff.br/riuff/handle/1/6956
Title: Composição da matéria orgânica nos estuários de Cairu e Camamu, BA
Authors: Mello, Tatiana Baptista Martinez
metadata.dc.contributor.advisor: Bernardes, Marcelo Corrêa
metadata.dc.contributor.members: Rezende, Carlos Eduardo
Knoppers, Bastiaan Adriaan
Albuquerque, Ana Luíza Spadano
Ometto, Jean Pierre Henry Balbaud
Issue Date: 2011
Abstract: O estu´ario de Cairu e a ba´ıa de Camamu est˜ao localizados no sul da Bahia, nordeste do Brasil. O objetivo deste estudo ´e determinar as principais fontes e processos que atuam nessas duas ´areas atrav´es da an´alise elementar e isot´opica do carbono e nitrog ˆenio de amostras de sedimentos superficiais como tamb´em sua composi¸c˜ao molecular, ester´ois e produtos da oxida¸c˜ao alcalina com CuO. A composi¸c˜ao isot´opica do carbono e nitrogˆenio apresentaram uma varia¸c˜ao maior no estu´ario de Cairu do que na ba´ıa de Camamu. Essa maior varia¸c˜ao em Cairu foi em fun¸c˜ao a sua geomorfologia particular, com ´areas que criam regi˜oes hidrodinˆamicamente distintas. Nos canais de contato com o mar a mat´eria orgˆanica (MO) ´e altamente influˆenciada pela mar´e, ent˜ao o 13C apresentou valores mais positivos, baixas concentra¸c˜oes de carbono orgˆanico (CO) e 8 (somat´orio dos grupos vanilil (V), siringil (S) e cinamil dos produtos da oxida¸c˜ao alcalina com CuO). Nas regi˜oes internas do estu´ario esse comportamento se inverte em fun¸c˜ao da alta contribui ¸c˜ao da MO da vegeta¸c˜ao de mangue e baixa hidrodinˆamica. Atrav´es da raz˜ao ´acido 3,5 dihidroxi benz´oico / V foi poss´ıvel identificar em Camamu ´areas onde a MO lixiviada da bacia de drenagem imprime seu sinal nos sedimentos. Nos setores Nilo Pe¸canha, Cairu e Valen¸ca, houve predominˆancia dos ester´ois que indicam plantas terrestres, como o estigmasterol. No setor Barra dos Carvalhos, os ester´ois colesterol, colestanol e colestanona predominaram, indicando a contribui¸c˜ao do fito e do zooplˆancton na MO sedimentar. No setor Boipeba, o estigmastanol - a forma degradada do estigmasterol - foi o composto mais abundante. Atrav´es da aplica¸c˜ao da t´ecnica de agrupamento Fuzzy C-Means, foi poss´ıvel identificar regi˜oes distintas em cada ´area de estudo. Na ba´ıa de Camamu, trˆes regi˜oes biogeoquimicamente diferentes foram identificadas em fun¸c˜ao da concentra¸c˜ao de V e S: ´areas de deposi¸c˜ao de MO oriunda de solos e mangue; ´area de mistura de fontes (manguezal e marinha), e a regi˜ao que recebe maior influˆencia fluvial. No estu´ario de Cairu, quatro regi˜oes distintas foram identificadas em fun¸c˜ao do teor de CO: ´area de alta deposi¸c˜ao de MO (solos e mangue); ´area de deposi¸c˜ao (mangue); ´area com mistura de fontes, por´em com predominˆancia do sinal do manguezal; e regi˜ao com diferentes massas d’´agua (fluvial e marinha).
metadata.dc.description.abstractother: The Cairu estuary and Camamu bay are located in southern Bahia, in the northeast of Brazil. The objective of this study is to determine the main sources and processes operating in these two areas by analyzing the elemental and isotopic composition of carbon and nitrogen of the superficial sediments samples, as well as its molecular composition, sterols and alkaline CuO oxidation products. The isotopic composition of carbon and nitrogen showed a greater variation in the estuary of Cairu than in Camamu. This greater variation in Cairu is due to its particular geomorphology, which creates distinct hydrodynamic regions. In the channels of contact with the sea, organic matter (OM) is highly influenced by the tide, so the 13C showed more positive values, and there were lower concentrations of organic carbon (OC) and 8 (sum of vanilil groups (V), syringyl (S) and cinnamyl alkaline CuO oxidation products). In the inner regions of the estuary this behavior is reversed due to the higher contribution of mangrove vegetation OM and slower hydrodynamic. Through the acid 3,5 dihydroxy benzoic/V ratio it was possible to identify in Camamu, OM leached areas where the drainage basin print their sign in sediments. In sectors Nilo Pe¸canha, Cairu and Valen¸ca, there was a predominance of sterols indicating terrestrial plants, like stigmasterol. In Barra dos Carvalhos sector, the sterols cholesterol, cholestanol and colestanona predominated, indicating the contribution of phytoplankton and zooplankton in the sedimentary OM. In Boipeba sector, the stigmastanol - which is a degraded form of stigmasterol - was the most abundant compound. By applying the Fuzzy C-Means (FCM) clustering method, it was possible to identify distinct regions in each study area. In Camamu Bay, three biogeochemically different areas were identified as a function V and S content: a soil and mangrove OM deposition area; a mixing area (mangrove and marine sources), and the region that received the greatest river influence. In Cairu estuary, four distinct regions were identified as a function OC content: the area of high OM deposition (soils and mangroves); depositional area (mangrove); an area with mixed sources, but with a predominance of mangrove signal; and the region with different water masses (river and sea water)
URI: https://app.uff.br/riuff/handle/1/6956
Appears in Collections:PPG-GEO - Teses e Dissertações

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