A liquid chromatographic technique using ultrastable-Y (US-Y) molecular sieve as the stationary phase and n-pentane as the mobile phase has been developed to fractionate and enrich pentacyclic triterpanes from petroleum. The sieve provides a shape-selective window which distinguishes between the various pentacyclic components, thus fractionating them on the basis of molecular shape differences. This sieving technique has been applied to isolate various pentacyclic triterpanes from sedimentary organic matter to enable better analysis of these biomarkers to be carried out.Biodegraded crude oils from three Australian basins were analysed to assess the geochemistry of their rearranged hopanes. Enhanced abundances of 25-norhopanes, 18(alpha)-30-norneohopane and diahopanes relative to the regular hopanes were observed in the most severely biodegraded samples. Geochemical interpretation of these results suggests that the enhanced abundances are due to the greater resistance of rearranged hopanes to biodegradation compared to regular hopanes. These studies also indicate that enhanced relative abundances of 25-norhopanes in these samples is most likely due to selective bacterial demethylation of (alpha beta)-hopane precursors.A branched and cyclic alkane fraction from a higher plant-derived crude oil was subjected to the US-Y chromatography procedure and the fractions eluted from the column were analysed using GC-MS. The compositions of the first two eluted fractions were markedly different from the initial branched and cyclic alkane mixture in that they were enriched in higher plant-derived triterpanes, such as bicadinanes, spirotriterpane and the oleananes and other, previously unreported, C(subscript)29 and C(subscript)30 triterpanes. A comparison of mass spectral data, GC retention and molecular sieve sorption characteristics of these compounds with those of known ++ / triterpanes of known molecular structure was used to suggest structures for the unknown compounds.Isolation of crude oil fractions enriched in pentacyclic alkanes using the sieving procedure enabled lower concentrations of bicadinanes to be detected than was previously possible by applying selective ion detection GC-MS to branched and cyclic alkane fractions. Application of this technique to a higher-plant derived Jurassic crude oil and two Jurassic sediments from the Eromanga Basin, Australia has revealed the presence of bicadinanes. The occurrence of the cis-cis-trans and trans-trans-trans bicadinane biomarkers that have previously only been reported from angiosperms may indicate an early evolution of flowering plant like species in this basin.The molecular sieving technique has also been used to isolate three pentacyclic triterpanes from low rank coals in order to obtain unambiguous structural identification and to determine their geochemical significance. A major hopanoid component isolated from a Victorian brown coal was characterised by single crystal X-ray diffraction and (subscript)13C NMR spectroscopy as 22R 17(alpha),21(beta)(H)-homohopane. This compound was shown to correspond to the later eluting 17(alpha),21(beta)(H)-homohopane and hence, for the first time, confirmed the common practice of assigning the higher retention time peak in gas chromatograms of (alpha beta) homohopanes as the 22R diastereomer. Heating of the isolated 22R (alpha beta)-homohopane on anthracite produced a mixture of the 22S and 22R diastereomers which implied a product-reactant relationship between the two epimers. Furthermore, a C(subscript)29 and a C(subscript)30 triterpane present in the hydrous pyrolysate of a Bremer Basin coal were also isolated using the molecular sieving procedure. 28 Nor-18(alpha)-oleanane was characterised by single crystal X-ray analysis while lupane was ++ / characterised by (subscript)13C NMR spectroscopy and by co-chromatography with an authentic standard on four different GC phase columns. The unusual occurrence of these triterpanes was attributed to the high sulphur content of the coal.Finally, laboratory isomerisation and reduction of an isomeric mixture of oleanenes was carried out to investigate the origin of oleanane (18(beta)-oleanane) and 18(alpha)-oleanane. Laboratory results indicated that oleanane was mainly derived from olean-18-ene, while 18(alpha)-oleanane was derived from 18(alpha)-olean-12-ene. Analysis of oleanene/oleanane abundances in a sedimentary sequence from Indonesia provided results consistent with laboratory evidence showing that 18(alpha)- olean-12-ene, rather than oleanane, is the main sedimentary precursor of 18(alpha)- oleanane.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-21T14:29:51Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO - RESENDE 2015.pdf: 1812905 bytes, checksum: a279042ee00914f24aa6181c3e1baafe (MD5) / Made available in DSpace on 2016-07-21T14:29:51Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO - RESENDE 2015.pdf: 1812905 bytes, checksum: a279042ee00914f24aa6181c3e1baafe (MD5) Previous issue date: 2015-09-27 / CNPq / Os estuários são ambientes importantes tanto do ponto de vista ecológico quanto econômico, estando frequentemente sob ação antrópica. A matéria orgânica (MO) depositada no sedimento estuarino pode ser de origem alóctone ou autóctone. O objetivo deste trabalho foi investigar a origem e a distribuição da MO no sedimento coletado no estuário do Rio Capibaribe (Recife – PE). Para tanto foram empregados marcadores geoquímicos elementares, isotópicos e moleculares. As amostras de sedimento foram coletadas em 18 estações ao longo do canal principal do estuário do Rio Capibaribe. Os resultados da análise granulométrica mostraram que houve predominância da fração lamosa no sedimento do estuário. A composição elementar mostrou que mais da metade das estações apresentaram predomínio de mistura de fontes marinha e terrestre. O percentual médio de carbono e nitrogênio reportados neste estudo apresentaram valores acima dos encontrados em estudos feitos em outros ambientes impactados. Os valores de δ13C ao longo do estuário apresentaram média de -24,45‰, com mais da metade deles dentro da faixa tipicamente encontrada em fontes de origem continental (oriunda de plantas C3). O valor médio de δ15N foi 8,34‰, indicando uma mistura de fontes com contribuição de efluentes. A concentração de hidrocarbonetos alifáticos (HAs) totais nas amostras de sedimento apresentou mediana de 178,89 μg g-1 peso seco, indicando que o estuário em questão se encontra contaminado por petróleo e seus derivados. As concentrações de hidrocarbonetos policíclicos aromáticos (HPAs) totais apresentaram mediana de 424,83 ng g-1 peso seco, indicando contaminação moderada desses compostos no sedimento do estuário, que são oriundos principalmente de fontes pirolíticas. Os resultados obtidos permitem deduzir que o ambiente estuarino do Rio Capibaribe está impactado pela ação antrópica e sua MO sedimentar recebe contribuições de fontes mistas oriunda de fontes marinhas e terrestres, incluindo descarga de esgotos. Além disso, há contaminação moderada de HAs e HPAs, respectivamente. Este último grupo é reconhecidamente tóxico para organismos e os níveis de diversos HPAs no sedimento do Capibaribe estão acima daqueles permitidos para sedimentos sujeitos a operações de dragagem (segundo a resolução 454/2012 do Conselho Nacional do Meio Ambiente). / Estuaries are key environments that are often under anthropogenic pressure. Organic matter (OM) of estuarine sediments may be from either allochthonous or autochthonous sources. This study investigated sources and fate of OM in sediments from the Capibaribe estuary (Recife, northeastern Brazil). Eighteen samples were collected along the main channel of the estuary. Analyses of grain size, elemental composition, stable isotopes and hydrocarbons were carried out in the samples. Grain size analysis showed that sediments are mainly comprised of mud (i.e., silt and clay particles). In over half of the samples, organic carbon and total nitrogen percentages evidenced a mixture of marine and terrigenous sources. The average percent composition of organic carbon and total nitrogen in the Capibaribe estuary is higher than in other impacted areas. The δ13C values in sediment averaged -24,45‰, with more than half of samples ranging within the C3 plants isotopic signature. The average δ15N value was 8,34‰, suggesting high input of anthropogenic effluents. Total concentration of aliphatic hydrocarbons (AHs) in sediment samples exhibited a median value of 178,89 μg g-1 dry weight, indicating moderate petroleum contamination. Total concentration of polycyclic aromatic hydrocarbons (PAHs) exhibited a median value of 424,83 ng g-1 dry weight. These levels indicate a moderate input of PAHs to the estuary. The data sets evidenced that the Capibaribe estuary is under significant anthropogenic pressure. The sedimentary OM is comprised of several sources, including sewage. PAHs are acknowledged to be toxic for organisms and some of them were detected in estuarine sediments at levels above those permitted by Brazilian regulations.

No description available.

The goal of this thesis was to characterize and quantify changes to Canadian Arctic organic matter (OM) induced by a physical disruption to the permafrost active layer by employing molecular-level techniques such as biomarker extraction and NMR to help elucidate its contribution to carbon turnover and global climate change. The initial biomarker characterization study determined that the extractable plant lipids were unaltered originating from the deposition of new vascular material or permafrost melt where a high alteration of lignin-derived OM was observed suggesting a long residence time in the ecosystem. Analysis of samples where there was a new and historical physical disruption to the permafrost landscape showed an initial increase in bacterial biomass biomarkers, and was corroborated with increased bacterial protein contributions and peptidoglycan signals in the NMR spectra. It is hypothesized that this increase in bacterial biomass resulted in a faster rate of degradation, possibly leading to OM priming.

Low molecular weight organic acids (LMWOAs) are important nutrients for microbes. However, most LMWOAs do not exist freely in the environment but are bound to macromolecular organic matter, e.g. kerogen, lignite and coal. During burial and geological maturation of sedimentary macromolecular organic matter biological and abiological processes promote the liberation of LMWOAs into the surrounding sediment. Through this process, microbes in sedimentary subsurface environments are supplied with essential nutrients. To estimate the feedstock potential of buried macromolecular organic matter to many environments it is important to determine the amount of LMWOAs that are bound to such a matrix. However, high-pressure and high temperature are a key feature of deep subsurface environments, and these physical parameters have a profound influence on chemical reaction kinetics. Therefore it is essential for the estimation of the feedstock potential to generate high-pressure and high temperature for the liberation of LMWOAs to recreate true in-situ conditions. This work presents a newly developed, inexpensive incubation system for biological and geological samples. It allows the application of high-pressure and high temperature as well as a subsampling of the liquid phase without loss of pressure, thereby not disturbing the on-going processes. When simulating the liberation of LMWOAs from sedimentary organic matter, the newly developed incubation system produces more realistic results than other extraction systems like Soxhlet. The extraction products remain in the extraction medium throughout the extraction, influencing the chemical conditions of the extraction medium. Sub-bituminous coal samples from New Zealand as well as lignite samples from Germany were extracted at elevated temperature (90˚C) and pressure (5 MPa). The main LMWOAs released from these low rank coals were formate, acetate and oxalate. Extraction efficiency was increased by two to four times for formate, acetate and oxalate in comparison to existing extraction methods without pressurisation and with demineralised water. This shows the importance of pressure for the simulation of true in-situ conditions and suggests that the amount of bioavailable LMWOAs is higher than previously thought. With the increase in carbon capture and storage (CCS) and the enhanced recovery of oil and gas (EOR/EGR), more and more CO2 becomes injected into the underground. However, the effects of elevated concentrations of carbon dioxide on sedimentary organic matter are rarely investigated. As the incuabtion system allows the manipulation of the composition and partial pressure of dissolved gasses, the effect of highly gas-enriched (CO2, CO2/SO2, CO2/NO2; to simulate flue gas conditions) waters on the extraction yield of LMWOAs from macromolecular organic matter was evaluated. For sub-bituminous coal the concentrations of all LMWAOs decreased upon the addition of gas, irrespective of its composition, whereas for lignite formate always and acetate mostly increased, while oxalate decreased. This suggests an positive effect on the nutrient supply for the subsurface microbiota of lignite layers, as formate and acetate are the most common LMWOAs used for microbial metabolism. In terrestrial mud volcanoes (TMVs), sedimentary material is rapidly ascending from great depth to the surface. Therefore LMWOAs that were produced from buried macromolecular organic matter at depth are also brought up to the surface, and fuel heterotrophic microbial ecosystems at the surface. TMVs represent geochemically and microbiologically diverse habitats, which are supplied with organic substrates and electron acceptors from deep-seated hydrocarbon-generating systems and intersected shallow aquifers, respectively. The main electron donor in TMVs in Azerbaijan is sulphate, and microbial sulphate reduction leads to the production of a wide range of reduced sulphur species that are key players in several biological processes. In our study we estimated the effect of LMWOAs on the sulphur metabolising activity of microorganims in TMVs from Azerbaijan. The addition of a mixture of volatile fatty acids containing acetate and other LMWOAs showed significant positive response to the sulphate reduction rate (SRR) of samples of several mud volcanoes. Further investigations on the temperature dependency of the SRR and the characterisation of thermophilic sulphate-reducing bacteria (SRB) showed a connection between the deep hot subsurface and the surface. / Niedermolekulare organische Säuren (nachfolgend als LMWOAs - low molecular weight organic acids - bezeichnet) stellen wichtige mikrobielle Substrate dar. Jedoch liegen die meisten LMWOAs nicht in freier, bioverfügbarer Form vor, sondern sind vielmehr an hochmolekulare organische Substanzen gebunden, z.B. Kerogen, Lignit und Kohle. Während der geologischen Verbringung in tiefe Erdschichten und der geologischen Reifung von sedimentären hochmolekularen organischen Substanzen, führen biologische und abiologische Prozesse zu einer Freisetzung von LMWOAs in die umgebenden Sedimente. Durch diesen Prozess werden Mikroorganismen in unterirdischen sedimentären Ökosystemen mit essentiellen Nährstoffen versorgt. Um das Nährstoffpotential tief liegender hochmolekularer organischer Substanzen für diverse Ökosystemen abschätzen zu können, ist es notwendig, die Menge an LMWOAs, die an solch eine hochmolekulare Matrix gebunden ist, zu bestimmen. Dabei stellen hoher Druck sowie hohe Temperatur entscheidende Faktoren in tiefen unterirdischen Ökosystemen dar, welche einen signifikanten Einfluss auf chemische Reaktionen haben. Daher ist es für die Abschätzung des Nährstoffpotentials entscheidend, hohen Druck und hohe Temperatur bei der Freisetzung von LMWOAs zu erzeugen, um wahre in situ Bedingungen zu schaffen. In der vorliegenden Arbeit wird ein neu entwickeltes, preiswertes Inkubationssystem für biologische und geologische Proben präsentiert. Es erlaubt die Verwendung von hohem Druck als auch hoher Temperatur sowie eine Unterprobennahme der flüssigen Phase ohne Druckverlust, um den fortlaufende Prozess nicht zu unterbrechen. Bei der Simulierung der Freisetzung von LMWOAs aus sedimentären organischen Substanzen erhält man mit dem neu entwickelten Inkubationssystem realistischere Resultate als mit anderen Extraktionssystemen, wie z.B. eine Soxhlet-Apparatur. Die Extraktionsprodukte verbleiben während der Extraktion im Extraktionsmedium, wodurch die chemischen Bedingungen verändert werden. Kohleproben aus Neuseeland sowie aus Deutschland wurden mittels erhöhter Temperatur (90°C) und Druck (5 MPa) extrahiert. Die wichtigsten LMWOAs, die aus diesen Kohlen freigesetzt wurden, waren Formiat, Acetat und Oxalat. Die Extraktionseffizienz für diese LMWOAs konnte im Vergleich zu existierenden Extraktionsmethoden ohne Druck um den Faktor 2 bis 4 gesteigert werden. Dies zeigt die Bedeutung von Druck bei der Simulation von in situ Bedingungen und legt nahe, dass die Menge an bioverfügbaren LMWOAs größer ist als bisher angenommen. Durch die Zunahme der CO2-Speicherung im Untergrund (carbon capture and storage, CCS) sowie der erweiterten Förderung von Öl und Gas (enhanced recovery of oil and gas, EOR/EGR) wird immer mehr CO2 in den Untergrund gepresst. Jedoch sind die Auswirkungen von erhöhten CO2-Konzentrationen auf sedimentäre organische Materie noch unerforscht. Da mit dem Inkubationssystem die Veränderung der Zusammensetzung und des Partialdruckes von gelösten Gasen möglich ist, wurde der Effekt von hoch mit Gasen (CO2, CO2/SO2, CO2/NO2; um Kraftwerksabgase zu simulieren) angereicherten Wässern auf die Extraktionsausbeute von LMWOAs untersucht. Bei der subbituminösen Kohle zeigte sich eine Abnahme aller LMWOAs-Konzentrationen durch die Lösung von Gas im Extraktionsmedium, wobei die Art des Gases keine Rolle spielte. Bei Lignit konnte hingegen festgestellt werden, dass die Extraktionsausbeute an Formiat immer und an Acetat meistens erhöht wurde, während sie sich bei Oxalat verringerte. Dies deutet auf einen positiven Effekt für die Nährstoffversorgung von Mikroorganismen um Lignit-Lagerstätten an, da Formiat und Acetat die am häufigsten verwendeten LMWOAs im mikrobiellen Stoffwechsel darstellen. In terrestrischen Schlammvulkanen (terrestrial mud volcanoes, TMVs) steigt sedimentäres Material aus großen Tiefen an die Erdoberfläche. Somit werden auch LMWOAs, welche aus hochmolekularen organischen Substanzen freigesetzt werden, an die Oberfläche verbracht, und ermöglichen dort heterotrophe Ökosysteme. TMVs stellen dabei geochemisch und mikrobiell unterschiedliche Habitate dar, welche mit organischen Substraten und Elektronenakzeptoren aus tief liegenden, Kohlenwasserstoffe erzeugenden Systemen versorgt werden. In TMVs in Aserbaidschan stellt Sulfat den Hauptelektronenakzeptor dar, wobei mikrobielle Sulfatreduktion zu einer Vielzahl an reduzierten Schwefelspezies führt. In der vorliegenden Arbeit wurde der Effekt von LMWOAs auf die Aktivität von Mikroorganismen bei der Umsetzung von Schwefel in TMVs in Aserbaidschan untersucht. Die Zugabe einer Mischung verschiedener kurzkettiger Fettsäuren zu Schlammproben verschiedener TMVs erzeugte eine signifikant positive Reaktion in Bezug auf die Sulfat-Reduktionsraten. Weiterführende Untersuchungen zur Temperaturabhängigkeit der Sulfat-Reduktionsraten und die Charakterisierung thermophiler, Sulfat-Reduzierender Bakterien zeigte eine Verbindung zwischen der tiefen, heißen Biosphäre und der Erdoberfläche auf.

The goal of this thesis was to characterize and quantify changes to Canadian Arctic organic matter (OM) induced by a physical disruption to the permafrost active layer by employing molecular-level techniques such as biomarker extraction and NMR to help elucidate its contribution to carbon turnover and global climate change. The initial biomarker characterization study determined that the extractable plant lipids were unaltered originating from the deposition of new vascular material or permafrost melt where a high alteration of lignin-derived OM was observed suggesting a long residence time in the ecosystem. Analysis of samples where there was a new and historical physical disruption to the permafrost landscape showed an initial increase in bacterial biomass biomarkers, and was corroborated with increased bacterial protein contributions and peptidoglycan signals in the NMR spectra. It is hypothesized that this increase in bacterial biomass resulted in a faster rate of degradation, possibly leading to OM priming.

Os ambientes costeiros marinhos são sítios de uma intensa produção, movimentação e enterramento de carbono orgânico, já que uma fração substancial do material orgânico produzido na zona eufótica deposita-se nos sedimentos e constitui a principal fonte de alimento para o bentos. O objetivo geral deste trabalho é estudar a influência da quantidade, origem e qualidade (composição bioquímica) da matéria orgânica sedimentar sobre a estrutura e distribuição vertical e horizontal da meiofauna e macrofauna bentônicas, em três ambientes com aportes diferenciados de matéria orgânica e submetidos a duas condições oceanográficas diferentes. Foram realizadas 2 campanhas de coleta em 6 estações localizadas no Canal de São Sebastião (CSS), Enseada de Caraguatatuba e Baía de Castelhanos. Em cada estação, foram analisadas as variáveis físico-químicas da água do mar, topografia do fundo, taxa de sedimentação atual. Coletaram-se amostras de sedimentos para análise das características granulométricas, concentração de pigmentos fotossintéticos, teores de matéria orgânica, carbono orgânico, nitrogênio e enxofre total, biopolímeros orgânicos (carboidratos, lipídios e proteínas), concentração e composição dos ácidos graxos, meiofauna e macrofauna, em sete horizontes da coluna sedimentar. As concentrações de pigmentos fotossintéticos, carbono orgânico, biopolímeros orgânicos, carbono biopolimérico e da razão PRT/CHO mostram que com exceção das estações 1 e 6, os sedimentos das demais áreas da região do CSS apresentam um certo grau de eutrofizacão e recebem um aporte importante de detritos orgânicos derivados da produção primária planctônica e bentônica, em diferentes estados de degradação. A composição dos ácidos graxos evidencia que a matéria orgânica particulada possui uma origem principalmente autóctone, e está constituída por uma combinação de material derivado do plâncton vivo ou detrítico, das microalgas bentônicas, da produção bacteriana e da fauna associada ao sedimento, havendo uma contribuição terrestre relativamente pequena. Nos locais estudados na região do CSS a quantidade do alimento não é um fator limitante; porém, a variação na sua qualidade em função de aportes esporádicos de matéria orgânica lábil, derivada da produção primária planctônica e bentônica, é um fator com importante influência na estruturação das comunidades bentônicas. / Coastal marine environments are places of intensive production, movement and burial of organic carbon, due to a considerable fraction of the organic material produced in the euphotic zone is deposited on sediments and represents the main food source for the benthos. The general aim of this work is to study the influence of sedimentary organic matter quantity, origin and quality (biochemical composition) on the structure, vertical and horizontal distribution of benthic meiofauna and macrofauna, in three environments with different organic inputs and under two different oceanographic conditions. Two sampling surveys were performed at 6 stations located in the São Sebastião Channel (SSC), Caraguatatuba Bight, and Castelhanos Bay. At each site the physico-chemical variables of marine water, bottom topography and the sedimentation rate were analyzed. Sediment samples were taken to analyze granulometric characteristics, photosynthetic pigment concentrations, organic matter, organic carbon, nitrogen and sulphur contents, organic biopolymers (carbohydrates, lipids and proteins), concentration and composition of fatty acids, meiofauna and macrofauna in seven sediment layers. Phytopigments, organic carbon, organic biopolymers and biopolymeric carbon concentrations and the PRT/CHO ratio show that excepting stations 1 and 6, the sediments of the other locations have a certain degree of eutrophication and receive a significant input of organic detritus derived from planktonic and benthic primary production at different stages of degradation. Fatty acids composition shows that the particulate organic matter has mainly an autochthonous origin and it is constituted by a mixture of material derived from live or dead plankton, benthic microalgae, bacterial production and from the resident fauna, having a relatively low terrestrial contribution. Food quantity is not a limiting factor at the studied sites in the SSC region; however, variability in food quality related to sporadic inputs of labile organic matter produced by planktonic and benthic primary producers, is an important structuring factor of benthic communities.

Este estudo constitui parte do Projeto Habitats Heterogeneidade Ambiental da Bacia de Campos coordenado pelo CENPES/Petrobras, um projeto multidisciplinar de caracterização ambiental que considera as diferentes feições e habitats da margem continental do sudeste brasileiro. O objetivo desta tese foi investigar os processos relacionados com a origem, o transporte e o acúmulo de matéria orgânica (MO) em sedimentos da margem continental da Bacia de Campos (RJ). Para isso, foram determinados a composição elementar da matéria orgânica (carbono e nitrogênio) por combustão a seco e os lipídios (esteróis, álcoois e ácidos graxos) por CG-MS e CG-DIC. Foram analisadas 215 amostras de sedimento superficial (0-2 cm de profundidade), coletadas em duas amostragens (períodos seco e chuvoso de 2008/2009), distribuídas sobre 12 isóbatas (de 25 a 3000 m) ao longo de 9 transectos de norte a sul da bacia. Além disto, foram ainda consideradas as isóbatas de 400 a 1900 m em dois cânions submarinos no norte da bacia (Almirante Câmara e Grussaí). Com base nos resultados obtidos, a MO sedimentar na plataforma e talude da bacia revelou-se essencialmente autóctone, derivada de produtores primários e secundários. Com isto, a MO contém uma fração reativa significativa e, portanto, é potencialmente biodisponível para os organismos bentônicos. No entanto, foram observados gradientes espaciais significativos na qualidade e na quantidade da MO sedimentar. Na plataforma continental (25 m a 150 m de profundidade) as concentrações de lipídios foram intermediárias e houve predomínio de MO sedimentar lábil. Exceções foram as áreas influenciadas por ressurgência costeira e/ou intrusão sub-superficial (próximo à Cabo Frio, Cabo de São Tomé e no limite norte da bacia), onde as concentrações foram altas. No talude superior e médio (400 a 1300 m) as concentrações de MO foram notadamente mais elevadas, mas com maior influência de processos bacterianos de alteração de sua composição original. E no talude inferior (1900 a 3000 m) as concentrações de MO estiveram muito baixas e apenas os lipídios mais resistentes à degradação bacteriana foram encontrados em concentrações mensuráveis. Isto sugeriu a exportação de materiais da plataforma ao longo do gradiente batimétrico, possivelmente decorrente da ação de meandros e vórtices da Corrente do Brasil e das correntes de fundo atuantes na região. Além disto, por ser lábil e biodisponível, a MO no sedimento apresenta uma fração biodisponível que pode ter uma influência na ecologia das comunidades bentônicas, particularmente aquelas localizadas no talude superior. Os cânions Grussaí e Almirante Câmara se revelaram regiões de acúmulo de MO e importantes no transporte da MO com valor nutritivo para comunidades bentônicas do talude médio e inferior. / This study is part of the Habitats Project - Campos Basin Environmental Heterogeneity - coordinated by CENPES/PETROBRAS, a multidisciplinary project that considers environmental characterization of the different features and habitats of the Brazilian South-Eastern continental margin. The aim of this thesis was to investigate the processes related to the origin, transport and accumulation of organic matter (OM) in sediments of the continental margin of the Campos Basin (RJ).To this end, the elemental composition of organic matter (carbon and nitrogen) - determined by dry combustion - and lipids (sterols, alcohols and fatty acids) - determined by GCMS and GC-FID - were considered. It was analyzed 215 samples of surface sediment (0-2 cm depth) collected in two samplings (dry and rainy seasons of 2008/2009), distributed over 12 isobaths (25 to 3000 m) along transects distributed from north to south of the basin. Moreover, it was also considered samples from the 400 to 1900 m isobaths in two submarine canyons (Almirante Câmara and Grussaí) in the northern basin. Based on the results, the sedimentary OM continental shelf and slope of Campos Basin was considered to be essentially autochthonous, derived from primary and secondary producers. As a consequence, a significant fraction of OM is reactive and therefore is potentially bioavailable to benthic organisms. However, significant spatial gradients in the quality and quantity of sedimentary OM were observed. In the continental shelf (25 m to 150 m depths), concentrations of lipids were intermediate and there was a predominance of labile sedimentary OM. Exceptions to this general feature were the areas influenced by coastal upwelling and/or sub-surface water intrusion (near Cabo Frio, Cabo de São Tomé and the northern boundary of the basin), where high concentrations of both total organic carbon and lipids were measured. In the upper and middle slope (400 to 1300 m) concentrations of OM were notably higher, but with greater influence of bacterial processes changing their original composition. And in the lower slope (1900 to 3000 m) concentrations of OM were very low and only the lipids more resistant to bacterial degradation were found in measurable concentrations. This suggested the export of materials from the continental shelf along the depth gradient, possibly due to the action of eddies and meanders of the Brazil Current and bottom currents operating in the region. Moreover, for its lability and bioavailability, the OM in the sediment can have a major influence on the ecology of benthic communities, particularly those located on the upper slope. The Almirante Câmara and Grussaí canyons revealed to be regions of OM accumulation and important features on the transport of OM with nutritional value for benthic communities of middle and lower slope.

Os ambientes costeiros marinhos são sítios de uma intensa produção, movimentação e enterramento de carbono orgânico, já que uma fração substancial do material orgânico produzido na zona eufótica deposita-se nos sedimentos e constitui a principal fonte de alimento para o bentos. O objetivo geral deste trabalho é estudar a influência da quantidade, origem e qualidade (composição bioquímica) da matéria orgânica sedimentar sobre a estrutura e distribuição vertical e horizontal da meiofauna e macrofauna bentônicas, em três ambientes com aportes diferenciados de matéria orgânica e submetidos a duas condições oceanográficas diferentes. Foram realizadas 2 campanhas de coleta em 6 estações localizadas no Canal de São Sebastião (CSS), Enseada de Caraguatatuba e Baía de Castelhanos. Em cada estação, foram analisadas as variáveis físico-químicas da água do mar, topografia do fundo, taxa de sedimentação atual. Coletaram-se amostras de sedimentos para análise das características granulométricas, concentração de pigmentos fotossintéticos, teores de matéria orgânica, carbono orgânico, nitrogênio e enxofre total, biopolímeros orgânicos (carboidratos, lipídios e proteínas), concentração e composição dos ácidos graxos, meiofauna e macrofauna, em sete horizontes da coluna sedimentar. As concentrações de pigmentos fotossintéticos, carbono orgânico, biopolímeros orgânicos, carbono biopolimérico e da razão PRT/CHO mostram que com exceção das estações 1 e 6, os sedimentos das demais áreas da região do CSS apresentam um certo grau de eutrofizacão e recebem um aporte importante de detritos orgânicos derivados da produção primária planctônica e bentônica, em diferentes estados de degradação. A composição dos ácidos graxos evidencia que a matéria orgânica particulada possui uma origem principalmente autóctone, e está constituída por uma combinação de material derivado do plâncton vivo ou detrítico, das microalgas bentônicas, da produção bacteriana e da fauna associada ao sedimento, havendo uma contribuição terrestre relativamente pequena. Nos locais estudados na região do CSS a quantidade do alimento não é um fator limitante; porém, a variação na sua qualidade em função de aportes esporádicos de matéria orgânica lábil, derivada da produção primária planctônica e bentônica, é um fator com importante influência na estruturação das comunidades bentônicas. / Coastal marine environments are places of intensive production, movement and burial of organic carbon, due to a considerable fraction of the organic material produced in the euphotic zone is deposited on sediments and represents the main food source for the benthos. The general aim of this work is to study the influence of sedimentary organic matter quantity, origin and quality (biochemical composition) on the structure, vertical and horizontal distribution of benthic meiofauna and macrofauna, in three environments with different organic inputs and under two different oceanographic conditions. Two sampling surveys were performed at 6 stations located in the São Sebastião Channel (SSC), Caraguatatuba Bight, and Castelhanos Bay. At each site the physico-chemical variables of marine water, bottom topography and the sedimentation rate were analyzed. Sediment samples were taken to analyze granulometric characteristics, photosynthetic pigment concentrations, organic matter, organic carbon, nitrogen and sulphur contents, organic biopolymers (carbohydrates, lipids and proteins), concentration and composition of fatty acids, meiofauna and macrofauna in seven sediment layers. Phytopigments, organic carbon, organic biopolymers and biopolymeric carbon concentrations and the PRT/CHO ratio show that excepting stations 1 and 6, the sediments of the other locations have a certain degree of eutrophication and receive a significant input of organic detritus derived from planktonic and benthic primary production at different stages of degradation. Fatty acids composition shows that the particulate organic matter has mainly an autochthonous origin and it is constituted by a mixture of material derived from live or dead plankton, benthic microalgae, bacterial production and from the resident fauna, having a relatively low terrestrial contribution. Food quantity is not a limiting factor at the studied sites in the SSC region; however, variability in food quality related to sporadic inputs of labile organic matter produced by planktonic and benthic primary producers, is an important structuring factor of benthic communities.

Este estudo constitui parte do Projeto Habitats Heterogeneidade Ambiental da Bacia de Campos coordenado pelo CENPES/Petrobras, um projeto multidisciplinar de caracterização ambiental que considera as diferentes feições e habitats da margem continental do sudeste brasileiro. O objetivo desta tese foi investigar os processos relacionados com a origem, o transporte e o acúmulo de matéria orgânica (MO) em sedimentos da margem continental da Bacia de Campos (RJ). Para isso, foram determinados a composição elementar da matéria orgânica (carbono e nitrogênio) por combustão a seco e os lipídios (esteróis, álcoois e ácidos graxos) por CG-MS e CG-DIC. Foram analisadas 215 amostras de sedimento superficial (0-2 cm de profundidade), coletadas em duas amostragens (períodos seco e chuvoso de 2008/2009), distribuídas sobre 12 isóbatas (de 25 a 3000 m) ao longo de 9 transectos de norte a sul da bacia. Além disto, foram ainda consideradas as isóbatas de 400 a 1900 m em dois cânions submarinos no norte da bacia (Almirante Câmara e Grussaí). Com base nos resultados obtidos, a MO sedimentar na plataforma e talude da bacia revelou-se essencialmente autóctone, derivada de produtores primários e secundários. Com isto, a MO contém uma fração reativa significativa e, portanto, é potencialmente biodisponível para os organismos bentônicos. No entanto, foram observados gradientes espaciais significativos na qualidade e na quantidade da MO sedimentar. Na plataforma continental (25 m a 150 m de profundidade) as concentrações de lipídios foram intermediárias e houve predomínio de MO sedimentar lábil. Exceções foram as áreas influenciadas por ressurgência costeira e/ou intrusão sub-superficial (próximo à Cabo Frio, Cabo de São Tomé e no limite norte da bacia), onde as concentrações foram altas. No talude superior e médio (400 a 1300 m) as concentrações de MO foram notadamente mais elevadas, mas com maior influência de processos bacterianos de alteração de sua composição original. E no talude inferior (1900 a 3000 m) as concentrações de MO estiveram muito baixas e apenas os lipídios mais resistentes à degradação bacteriana foram encontrados em concentrações mensuráveis. Isto sugeriu a exportação de materiais da plataforma ao longo do gradiente batimétrico, possivelmente decorrente da ação de meandros e vórtices da Corrente do Brasil e das correntes de fundo atuantes na região. Além disto, por ser lábil e biodisponível, a MO no sedimento apresenta uma fração biodisponível que pode ter uma influência na ecologia das comunidades bentônicas, particularmente aquelas localizadas no talude superior. Os cânions Grussaí e Almirante Câmara se revelaram regiões de acúmulo de MO e importantes no transporte da MO com valor nutritivo para comunidades bentônicas do talude médio e inferior. / This study is part of the Habitats Project - Campos Basin Environmental Heterogeneity - coordinated by CENPES/PETROBRAS, a multidisciplinary project that considers environmental characterization of the different features and habitats of the Brazilian South-Eastern continental margin. The aim of this thesis was to investigate the processes related to the origin, transport and accumulation of organic matter (OM) in sediments of the continental margin of the Campos Basin (RJ).To this end, the elemental composition of organic matter (carbon and nitrogen) - determined by dry combustion - and lipids (sterols, alcohols and fatty acids) - determined by GCMS and GC-FID - were considered. It was analyzed 215 samples of surface sediment (0-2 cm depth) collected in two samplings (dry and rainy seasons of 2008/2009), distributed over 12 isobaths (25 to 3000 m) along transects distributed from north to south of the basin. Moreover, it was also considered samples from the 400 to 1900 m isobaths in two submarine canyons (Almirante Câmara and Grussaí) in the northern basin. Based on the results, the sedimentary OM continental shelf and slope of Campos Basin was considered to be essentially autochthonous, derived from primary and secondary producers. As a consequence, a significant fraction of OM is reactive and therefore is potentially bioavailable to benthic organisms. However, significant spatial gradients in the quality and quantity of sedimentary OM were observed. In the continental shelf (25 m to 150 m depths), concentrations of lipids were intermediate and there was a predominance of labile sedimentary OM. Exceptions to this general feature were the areas influenced by coastal upwelling and/or sub-surface water intrusion (near Cabo Frio, Cabo de São Tomé and the northern boundary of the basin), where high concentrations of both total organic carbon and lipids were measured. In the upper and middle slope (400 to 1300 m) concentrations of OM were notably higher, but with greater influence of bacterial processes changing their original composition. And in the lower slope (1900 to 3000 m) concentrations of OM were very low and only the lipids more resistant to bacterial degradation were found in measurable concentrations. This suggested the export of materials from the continental shelf along the depth gradient, possibly due to the action of eddies and meanders of the Brazil Current and bottom currents operating in the region. Moreover, for its lability and bioavailability, the OM in the sediment can have a major influence on the ecology of benthic communities, particularly those located on the upper slope. The Almirante Câmara and Grussaí canyons revealed to be regions of OM accumulation and important features on the transport of OM with nutritional value for benthic communities of middle and lower slope.