A Baía da Guanabara vem sofrendo alterações na sua bacia de drenagem desde o início do século XIX que resultaram em acentuada degradação ambiental. O presente trabalho discute a influência da implantação de um Terminal Aquaviário de Gás Natural Liquefeito (GNL) na Baía, e suas possíveis influências nos processos de sedimentação local e/ou re-disponibilização de sedimentos de fundo, e possíveis contaminantes associados. Os resultados dos modelos matemáticos mostram que as maiores velocidades das plumas termicas que atingem o fundo são em média 0,46 m3/s para as simulações de verão e 0,47 m3/s para as simulações de inverno, sendo que são necessários pelo menos de 0,50 m3/s para uma corrente erodir o fundo, porem velocidades na faixa de 20 a 50 m3/s são suficientes para causar erosão de sedimentos finos inconsolidados. Sendo assim, a influência das plumas térmicas geradas no processo de re-gaseificação do GNL é de pequena magnitude, e suas correntes só conseguem exportar estes sedimentos para distancias inferiores a 1000 m. Em relação a re-disponibilização de contaminantes associados aos sedimentos de fundo se mostrou pouco provável, dado o fato da qualidade dos sedimentos apresentarem, diferente da água, baixa concentração de contaminantes e da baixa competência de erosão, que eles tenham competência para erodir sedimentos consolidados. / Since the beginning of the XIX century, interventions on the Guanabara\'s Bay drainage basin result in severe environmental degradation. This work aimed to analyze the implementation of an Aquaviary Terminal of Liquefied Natural Gas (LNG), and its putative consequences on the local sedimentation processes, and the availability and possible associated contaminants of the bottom sediments. According to the mathematical models developed, the means of the greatest speeds of the thermal plumes that reach the bottom are 0.46m3/s for the summer simulations and 0.47m3/s for the winter. However, for a current to be able to erode the bottom it must be of at least 50m3/s. Currents with speeds ranging from 20 to 50m3/s are sufficient only to cause the erosion of fine and non-consolidated sediment. Therefore, the thermal plumes generated in the process of re-gasification of the LNG are of little magnitude, and will not be able to export these sediments to any distance greater than 1000 meters. The re-availability of the contaminants associated with the bottom sediments is not likely, once these sediments, differently from the water, showed little concentration of contaminants. In addition, with the low erosion capacity of the currents generated, the consolidated sediments are not likely to be eroded.

Aquatic sediments are, by surface, the largest habitat on Earth. A wide diversity of organisms inhabit these sediments and by their actions they have a large influence on and also mediate many ecosystem processes. Several of these processes, such as decomposition and remineralisation of organic matter are important on a global scale and are essential to sustain life on Earth. The main aim of this thesis was to use an experimental ecosystem ecology approach in order to study some of these ecosystem processes in marine sediments and how they are linked to biodiversity. Paper I and II found that an increased species richness of sediment deposit feeders increases the processing of organic matter from phytoplankton settled on the sea-floor, and that species-rich communities have a more efficient resource utilization of deposited organic matter. The results in paper IV and V also suggest that there is a link between microbial diversity in sediments and the degradation of organic contaminants. Paper V also shows that antibiotic pollution is a potential threat to natural microbial diversity and microbially mediated ecosystem services. The introduction of invasive species to ecosystems is another major threat to biodiversity and was studied in Paper II and III, by investigating the ecology of Marenzelleria arctia, a polychaete worm recently introduced in the Baltic Sea. Paper II suggests that M. arctia mainly utilize food resources not used by native deposit feeders, thus potentially increasing the benthic production in the Baltic Sea by increasing resource use efficiency. Paper III, however, show that M. arctia is protected from predation by the native benthic invertebrate predators, due to its ability to burrow deep in the sediment, suggesting that predation on M. arctia by higher trophic levels is restricted, thereby limiting trophic transfer. In conclusion, this thesis gives some examples of the importance of marine biodiversity for the generation of a few key ecosystem processes, such as organic matter processing and the degradation of harmful contaminants. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: In press.

Made available in DSpace on 2014-12-17T14:08:43Z (GMT). No. of bitstreams: 1 MariaSMQ_DISSERT_1-36.pdf: 5283210 bytes, checksum: e75f1aa1d6f8e40607338226667f1b0d (MD5) Previous issue date: 2011-02-07 / Estuaries are environments prone to the input of chemical pollutants of various kinds and origins, including polycyclic aromatic hydrocarbons (PAHs). Anthropogenic PAHs may have two possible sources: pyrolytic (with four or more aromatic rings and low degree of alkylation) and petrogenic (with two and three aromatic rings and high degree of alkylation). This study aimed to evaluate the levels, distribution and possible sources of polycyclic aromatic hydrocarbons in the estuary of the Potengi river, Natal, Brazil. Samples of bottom sediments were collected in the final 12 km of the estuary until its mouth to the sea, where the urbanization of the Great Natal is more concentrated. Sampling was performed on 12 cross sections, with three stations each, totaling 36 samples, identified as T1 to T36. The non alkylated and alkylated PAHs were analyzed by gas chromatography coupled to mass spectrometry (GC / MS). PAHs were detected in all 36 stations with total concentration on each varying 174-109407 ng g-1. These values are comparable to those of several estuarine regions worldwide with high anthropogenic influence, suggesting the record of diffuse contamination installed in the estuary. PAHs profiles were similar for most stations. In 32 of the 36 stations, low molecular weight PAHs (with 2 and 3 ring: naphthalene, phenanthrene and their alkylated homologues) prevailed, which ranged from 54% to 100% of the total PAH, indicating that leaks, spills and combustion fuels are the dominant source of PAH pollution in the estuary. The level of contamination by PAHs in most stations suggests that there is potential risk of occasional adverse biological effects, but in some stations adverse impacts on the biota may occur frequently. The diagnostic ratios could differentiate sources of PAHs in sediments of the estuary, which were divided into three groups: petrogenic, pyrolytic and mixing of sources. The urban concentration of the Great Natal and the various industrial activities associated with it can be blamed as potential sources of PAHs in bottom sediments of the estuary studied. The data presented highlight the need to control the causes of existing pollution in the estuary / Os estu?rios s?o ambientes prop?cios ao aporte de poluentes qu?micos de diversas naturezas e origens, incluindo Hidrocarbonetos Polic?clicos Arom?ticos (HPA). Os HPA antr?picos s?o de duas fontes poss?veis: pirol?tica (com quatro ou mais an?is arom?ticos e baixo grau de alquila??o) e petrog?nica (com dois e tr?s an?is arom?ticos e alto grau de alquila??o). O presente trabalho teve como objetivo avaliar os n?veis, distribui??o e poss?veis fontes de Hidrocarbonetos Polic?clicos Arom?ticos no estu?rio do rio Potengi, Natal-RN. Amostras de sedimentos de fundo foram coletadas nos 12 km finais do estu?rio at? a sua foz, onde a urbaniza??o da Grande Natal ? mais concentrada. A amostragem foi realizada em 12 se??es transversais, com tr?s esta??es em cada uma, totalizando 36 amostras, identificadas de T1 a T36. Os HPA alquilados e n?o alquilados foram analisados por cromatografia gasosa acoplada a um detector seletivo de massas (CG/EM). Foram detectados HPA em todas as 36 esta??es, com concentra??o total em cada uma variando de 174 a 109407 ng g-1. Esses valores s?o compar?veis aos de v?rias regi?es estuarinas mundiais com grande influ?ncia antr?pica, o que sugere o registro de contamina??es difusas instaladas no estu?rio. O perfil de HPA foi similar para a maioria das esta??es. Em 32 das 36 esta??es predominaram HPA de baixo peso molecular (com 2 e 3 an?is: naftaleno, fenantreno e seus hom?logos alquilados), que variaram de 54% a 100% em rela??o ao total de HPA, indicando que vazamentos, derramamentos e queima de combust?veis s?o a fonte dominante de polui??o por HPA no estu?rio. O n?vel de contamina??o por HPA na maioria das esta??es sugere que h? risco potencial de ocasionais efeitos biol?gicos adversos serem observados, por?m em algumas esta??es se confirmam que impactos adversos sobre a biota ocorrem com freq??ncia. As raz?es diagn?sticas permitiram diferenciar as fontes de HPA nos sedimentos do estu?rio, que foram divididos em tr?s grupos: sedimentos com padr?es de introdu??o de hidrocarbonetos petrog?nicos, pirol?ticos e de mistura de fontes. A concentra??o urbana da Grande Natal e as atividades industriais diversas a ela associadas podem ser responsabilizadas como fontes potenciais dos HPA nos sedimentos de fundo do estu?rio estudado. Os dados apresentados evidenciam a necessidade de se controlar as causas da polui??o existente no estu?rio

Made available in DSpace on 2015-02-24T19:48:45Z (GMT). No. of bitstreams: 1 AdrianaBG_capa_ate_secao5.pdf: 3230514 bytes, checksum: e499db1cdb9c0ab6b161220ff77e224a (MD5) Previous issue date: 2006-10-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Curimata? estuary is located in the oriental coast of Rio Grande do Norte State in Brazil. Its importance resides in the fact that this region possesses one of the last portions of preserved mangrove in the Rio Grande do Norte State. Nevertheless, it has been severely affected by many anthropogenic activities, as sugarcane monoculture and shrimp farming. Former works demonstrated that an accumulation of heavy metals is occurring in oysters in this estuary, and perhaps it could be explained by the input of metals in this ecosystem deriving from the shrimp farming. To better understanding the origin of these metals, bottom sediment samples, cores and suspended particulate matter were collected for a characterization of metal concentrations (Al, Ba, Cd, Cu, Cr, Fe, Mn, Ni, Pb, Zn) and to determine the potentially bioavailable metals. Additionally, the enrichment ratio for each element analyzed was calculated. The mineralogical composition of sediment samples and cores were obtained by X-ray diffraction. Moreover, data of orbital remote sensing were used in order to detect and quantify suspended matter by applying a logarithmic algorithm. Geochemical data of bottom sediments and cores revealed that, excepting Ba and Pb, the elements analyzed presented concentrations characteristic of an unpolluted ecosystem (Al: 0,25 - 8,76 %; Ba: 3,03 - 870 ?g.g-1; Cd: < 0,25 ?g.g-1; Cr: 1,72 - 82,4 ?g.g-1; Cu: 0,12 -25,3 ?g.g-1; Pb: 0,38 - 23,7 ?g.g-1; Fe: 0,10 - 5,82 %; Mn: 15,1 - 815 ?g.g-1; Ni: 0,14 - 36,1 ?g.g-1; Zn: 1,37 - 113 ?g.g-1). During the dry season a distribution pattern was observed, with higher metal concentrations in the margins, decreasing toward the central portion of the channel. These metal concentrations were well correlated with mineralogical compositions, with clay minerals prevailing at the margins, and quartz and feldspar in the center. However, this pattern was not observed during the wet season, probably because of the high water flux that disturbed bottom sediments. But, as observed for the dry season, a good correlation between metal concentrations and mineralogical composition was also observed for the wet season, with high metal concentrations where there were high quantities of clay minerals. Low enrichment ratios were obtained for the majority of elements analyzed, excepting for Mn, Ba and Pb. Manganese presented the higher ratios downstream for both seasons, and it can be an evidence of anthropogenic impact by shrimp farming. As barium and lead concentrations in sediment samples presented analytical problems during the total sample digestion, one cannot be sure that the ratios obtained correspond to the reality. The highest metal concentrations in particulate matter were obtained in the portion dominated by fluvial transport for all metals analyzed, excepting for copper. Barium and zinc were the only elements that presented elevated concentrations that are not common of unpolluted ecosystems (Ba: 5730 - 8355 ?g.g-1; Zn: 3899 - 4348 ?g.g-1). However, these high concentrations could not be related to the shrimp farming and waste waters from the town of Canguaretama, once they were obtained from the fluvial particulate matter, that is upstream from the activities above mentioned. The application of the logarithmic algorithm to the processed LANDSAT image was well succeeded, although the acquired image does not correspond exactly to the field campaigns. The IKONOS image provided very detailed views of the suspended sediment concentration at the estuary, as the mixture of distinct water flows at the confluence of Cunha? and Curimata? rivers, with more turbid waters from Cunha? river, that is directly affected by effluents from shrimp farming and urban waste waters deriving from the town of Canguaretama / O estu?rio do rio Curimata? localiza-se na por??o sul do litoral oriental do Estado do Rio Grande do Norte, apresentando uma das ?ltimas por??es de manguezais no Estado. Este ecossistema tem sido fortemente afetado por diversas atividades antropog?nicas, como o cultivo de cana-de-a??car, a carcinicultura, al?m da urbaniza??o. Trabalhos anteriores neste local revelaram que ostras Crassostrea rhizophorae apresentaram concentra??es de alguns metais acima dos limites permitidos para consumo, e que talvez a entrada destes metais no estu?rio estivesse relacionada aos efluentes de carcinicultura. Para uma melhor compreens?o da origem destes metais, foram coletadas amostras de sedimento de fundo, testemunhos e material particulado em suspens?o para uma caracteriza??o das concentra??es de dez elementos maiores e tra?os (Al, Ba, Cd, Cu, Cr, Fe, Mn, Ni, Pb, Zn), bem como para a determina??o dos elementos potencialmente biodispon?veis. Al?m disso, tamb?m foi realizado o c?lculo da raz?o de enriquecimento para cada elemento analisado. A composi??o mineral?gica das amostras de sedimento de fundo e dos testemunhos foi obtida atrav?s de difratometria de raios-X. Adicionalmente, dados de sensoriamento remoto orbital foram usados a fim de se detectar e semiquantificar o material particulado em suspens?o atrav?s da aplica??o de um algoritmo logar?tmico. As an?lises geoqu?micas das amostras de sedimento de fundo revelaram que os elementos analisados apresentaram concentra??es caracter?sticas de um estu?rio n?o polu?do (Al: 0,25 a 8,76%; Ba: 3,03 a 870 ?g.g-1; Cd: < 0,25 ?g.g-1; Cr: 1,72 a 82,4 ?g.g-1; Cu: 0,12 a 25,3 ?g.g-1; Pb: 0,38 a 23,7 ?g.g-1; Fe: 0,10 a 5,82 %; Mn: 15,1 a 815 ?g.g-1; Ni: 0,14 a 36,1 ?g.g-1; Zn: 1,37 a 113 ?g.g-1). Um padr?o de distribui??o dos metais foi observado durante a esta??o seca, com maiores concentra??es nas margens, diminuindo em dire??o ao centro do canal. A concentra??o dos metais se mostrou bem correlacionada com as respectivas composi??es mineral?gicas das amostras de sedimento, com minerais de argila predominando nas margens, e quartzo e feldspato mais presentes no centro do canal. Contudo, este padr?o n?o foi observado durante a esta??o chuvosa, provavelmente devido ao fluxo de ?gua mais intenso que promoveu o dist?rbio dos sedimentos de fundo, com remo??o da fra??o fina das margens. Mas, da mesma forma que observado para a esta??o seca, nas amostras coletadas durante a esta??o chuvosa tamb?m se observou maiores concentra??es de metais nas amostras com predom?nio de minerais argilosos. Raz?es de enriquecimento sugestivas de aus?ncia de polui??o foram obtidas para a maioria dos elementos analisados, com exce??o de Mn. O mangan?s apresentou as maiores raz?es ? jusante da atividade de carcinicultura, as quais sugerem polui??o significativa neste trecho durante ambas as esta??es seca e chuvosa. Esta pode ser uma evid?ncia do impacto da carcinicultura no estu?rio, j? que a montante desta atividade a raz?o de enriquecimento foi baixa. No material particulado em suspens?o as maiores concentra??es de metais foram obtidas na por??o dominada pelo transporte fluvial para todos os elementos analisados, com exce??o do cobre. Os ?nicos elementos que apresentaram concentra??es elevadas, incomuns para ambientes livres de polui??o, foram b?rio (de 5730 a 8355 ?g.g-1) e zinco (de 3899 a 4348 ?g.g-1). Contudo, estas concentra??es anormais aparentam n?o estar relacionadas ? carcinicultura ou aos efluentes da cidade de Canguaretama, uma vez que foram encontrados ? montante destas atividades. A aplica??o do algoritmo logar?tmico ? imagem LANDSAT foi bem sucedida, embora a imagem adquirida n?o corresponda exatamente ?s datas de coleta do material em suspens?o. A imagem IKONOS forneceu vis?es muito detalhadas do estu?rio que permitiram observar a distribui??o do material particulado, com a mistura de fluxos de ?gua distintos na conflu?ncia dos rios Cunha? e Curimata?, sendo que o rio Cunha? apresenta ?guas mais turvas, e ? diretamente afetado pelos efluentes de carcinicultura e dejetos urbanos da cidade de Canguaretama