Thesis advisor: Noah Snyder / Rivers impounded by dams experience morphological changes that provide an opportunity to calculate reservoir sedimentation rates and relate them to watershed land-use history. In April 2023, 10 sediment cores were collected from 5 locations in Lake Seminole, Georgia. Analysis of loss on ignition (LOI), bulk density, elemental concentrations, and short-lived radionuclide geochronology aided in completing the following research objectives: correlating short and long sediment cores, determining whether the pre-dam sediment surface was reached at each location, measuring the sedimentation rates in the Chattahoochee and Flint arms of the reservoir, and evaluating the characteristics of each core in the context of its location and the history of Lake Seminole. This research explores how differences in river management, land use, and upstream geology in the watersheds have contributed to sedimentation differences in the Chattahoochee and Flint Rivers. / Thesis (BS) — Boston College, 2024. / Submitted to: Boston College. Morrissey School of Arts and Sciences. / Discipline: Earth and Environmental Sciences. / Discipline: Departmental Honors.

Annually and subannually laminated lacustrine sediments potentially contain a wide range of information that can be interpreted for paleoenvironmental reconstructions. These laminae are produced by the physical and biological processes that operate in the lake and in the surrounding terrestrial environment. However, identification of the influences that control laminae production may not be straightforward, and other processes may subtly influence the overall depositional sequence. This thesis examines two different depositional environments on Colin Archer Peninsula, Devon Island, Canada, with the objective of identifying the factors that influence subannual sediment deposition and how the resultant sedimentary structures can be used as indicators of paleoenvironmental conditions. In proglacial Lake R, clastic sediment deposition is controlled primarily by subannual meteorological conditions. Periods of positive air temperature or large rainfall events produce discernable laminae that, when combined, form a varve sequence. However, overarching geomorphic controls influence the delivery of sediment to the lake and may reduce or enhance the hydrometeorological signal contained in the varves. An additional influence for calibration of the varve record to meteorological observations is the role that melt season thermal inversions have on temperature extrapolation in the High Arctic. Meteorological stations at sea level may not be representative of the surrounding region, thereby reducing the accuracy of vertical temperature estimation. Investigation of the inversions in the central Canadian High Arctic demonstrated that melt season inversions are common and increased inversion frequency may potentially have influenced enhanced glacial melt since the late 1980s, with implications for proglacial lake sediment transport and deposition. In coastal Lake J, late Holocene sediments record a relatively unusual accumulation of microbially induced sedimentary structures (MISS). Such a record has not been previously described in the circum-Arctic, although they are known to exist elsewhere. These sediments are produced by the interaction between clastic sedimentation and cyanobacterial growth and production. Although chronological constraint could not be assigned with certainty to the record, statistical study of the laminated sequence suggested a dominant pattern that is plausibly annual. A heuristic model of annual sediment accumulation was developed in order to explore the potential for quasi-annual paleoenvironmental interpretations. / Thesis (Ph.D, Geography) -- Queen's University, 2008-05-22 09:55:12.184

O presente estudo visou reconstruir o histórico de impactos antrópicos na bacia de drenagem do Lago das Garças durante o século XX por meio da deposição de contaminantes no compartimento sedimentar. O Lago das Garças está localizado em uma unidade de conservação, Parque Estadual das Fontes do Ipiranga (PEFI), inserida em área altamente povoada e urbanizada da cidade de São Paulo. Dois testemunhos de sedimento (LG05-03 e LG05-04, com 70 cm e 65 cm, respectivamente) foram amostrados mediante auxílio de mergulhadores no ponto mais profundo do reservatório, sendo, posteriormente, fatiados a cada 1 cm. Em LG05-03 foram quantificadas as distribuições verticais de carbono orgânico total (COT), nutrientes totais (NT e PT), hidrocarbonetos policíclicos aromáticos (HPA), hidrocarbonetos alifáticos (n-alcanos), bem como foi feita a classificação granulométrica. Em LG05-04 foi determinada a deposição de metais pesados (Co, Cr, Cu, Fe, Mn, Ni, Pb e Zn) e a geocronologia através do isótopo radioativo \'ANTPOT. 210 Pb\', usando o modelo CIC (Constant Initial Concentration). Os dados foram analisados por meio de análises estatísticas multivariadas (ACP: Análise de Componentes Principais). Com base nas tendências dos dados e na ACP, foi possível estabelecer três fases principais: Fase I: 64-43 cm (~1894-1975): caracterizada por baixas concentrações de nutrientes e contaminantes, sendo possível recuperar níveis préindustriais destes compostos, propostos como valores de referência regionais. Ainda, com base na razão C/N e em razões entre n-alcanos, notou-se, nesta fase o predomínio de aporte de matéria orgânica de origem alóctone; Fase II: 43-26 cm (~1975-1990): aumento abrupto das concentrações de metais pesados e HPA traçadores de veículos automotores, marcando o aumento da poluição atmosférica devido ao grande crescimento econômico do município e maior circulação de veículos na região. Ainda, foi observado aumento gradual das concentrações de NT e PT, atribuídos aos despejos de esgotos não tratados oriundos da Secretaria de Agricultura e Abastecimento e da Fundação Parque Zoológico; Fase III: 26-0 cm (~1990-2005): aumento mais acentuado das concentrações de nutrientes devido aos despejos de esgotos, acarretando em maior eutrofia do sistema, registrada pelo perfil do n-\'C IND.17\'. Pico das concentrações de HPA traçadores do uso de carvão mineral associado às atividades de uma siderúrgica vizinha (Siderúrgica J.L. Alipeti), bem como queda das concentrações destes traçadores coincidindo com mudanças no processo industrial da empresa. Ainda nesta fase notaram-se aumentos expressivos dos teores e fluxos dos HPA traçadores de veículos automotores, corroborando o cenário de aumento vertiginoso da frota de veículos na última década. Desse modo, este estudo contribuiu com o cenário nacional em termos de manejo de bacias hidrográficas urbanas, incluindo registros desde a época pré-revolução industrial no Brasil (~1894) até os dias atuais, demonstrando o potencial do uso de testemunhos lacustres no resgate de informações relativas à contaminação de ecossistemas aquáticos associadas às atividades antropogênicas. / Present study aimed to reconstruct the human impact history on the Garças Lake Drainage Basin during the 20th Century based on contaminants deposition on the lacustrine sediment. Garças Lake is located in a preservation area, the Parque Estadual das Fontes do Ipiranga (PEFI), located in a highly populated urban area within the city of São Paulo. Two sediment cores (LG05-03 and LG05-04, 70 cm and 65 cm long) were sampled by divers at the deepest site of the lake, which were sliced at 1 cm intervals. Information for LG05-03 included total organic carbon (TOC), total nutrients (TN and TP), polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons (n-alkanes) and grain size vertical distributions. Deposition of heavy metals (Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and the geocronology by \'ANTPOT. 210 Pb\', using CIC model (Constant Initial Concentration), were determined in LG05-04. Data were analyzed by multivariate statistic analysis (PCA, principal components analysis). Based on data trends and PCA, it was possible to recognized three main phases: Phase I: 64-43 cm (~1894-1975) characterized by low nutrients and contaminants concentrations, allowing retrieving preindustrial levels of these compounds, which are proposed as regional reference values. Besides, C/N ratio and n-alkanes ratios demonstrated aloctonous organic matter predominance; Phase II: 43-26 cm (~1975-1990) characterized by the abrupt increase of heavy metals and vehicular PAHs concentration, indicating the atmospheric pollution increase, due to the great economic rise experienced by the city of São Paulo over that time and the higher vehicles circulation in the region. Yet, it was observed a gradual increase in nutrient concentration attributed to the untreated sewage inputs from the São Paulo State Department of Agriculture and Provisioning headquarters and the city Zoo; Phase III: 26-0 cm (~1990-2005) characterized by a marked increase in nutrient concentration related to the untreated sewage inputs, leading to the increase of eutrophication, as registered by the n-\'C IND.17\' distribution. A peak of coal PAHs concentration was also noticed, related to a neighbor steel mill (J.L. Aliperti), followed by a subsequent decrease of these compounds, coincident with industrial procedures changes. Besides, there was an expressive increase in vehicular PAHs concentrations, corroborating the scenery of a drastic raise of vehicles in the last decade. The present study contributed to the national scenario towards urban drainage basin management. It included records since preindustrial time (~1894) up to the present, highlighting the potential use of lacustrine sediment on the retrieval of historical environmental changes of aquatic ecosystems and associated anthropogenic impacts.

Cette étude propose une analyse intégrée de biomarqueurs moléculaires de sols, depuis leur site de production jusqu'à leur archivage sédimentaire lacustre. Un inventaire des lipides neutres est d'abord réalisé sur des sols d'usages contrastés : prairies/pâtures et forêts. Globalement, cette approche permet de distinguer (1) des composés linéaires ubiquistes, et (2) des composés (poly-)cycliques, généralement spécifiques. Parmi ces derniers figurent les acétates de triterpényle et les méthoxyserratènes, respectivement biomarqueurs d'Astéracées et de Pinacées. La persistance de l'empreinte moléculaire d'un ancien usage des sols est aussi démontrée. Ensuite, l'analyse multi-proxy d'une carotte sédimentaire couvrant les 6700 dernières années révèle l'impact prépondérant des activités humaines sur le fonctionnement hydrologique du lac, depuis l'époque gallo-romaine. Les assemblages moléculaires précédemment définis dans les sols sont globalement retrouvés, associés à un nouveau biomarqueur spécifique du chanvre, d'intérêt paléoenvironnemental. Une tentative de reconstitution des anciennes occupations des sols apparaît conforme aux données historiques et paléoenvironnementales antérieures. / This study proposes an integrated analysis of molecular biomarkers of landuse, from their genesis in soils to their archiving in the lacustrine sediment. An inventory of neutral lipids is realized on soils of two contrasted landuses: grassland/pasture and forest. This approach globally allows to distinguish (1) ubiquist linear compounds and (2) (poly-)cyclic compounds, generally specific. Among these ones, triterpenyl acetates and methoxyserratenes are detected and are respectively biomarkers of Asteraceae and Pinaceae. The persistence of a molecular imprint of an ancient landuse is also demonstrated. Then, the multi-proxy analysis of a sedimentary core, covering the last 6700 years, shows the prominent impact of human activities on the hydrologic functioning of the lake since the gallo-roman period. Molecular assemblages previously defined in soils are globally detected in sediments, associated with a new specific biomarker of hemp, of palaeoenvironmental interest. Hypotheses for the reconstitution of past landuses appear to be consistent with previous historical and palaeoenvironmental data.

Made available in DSpace on 2017-07-10T14:38:17Z (GMT). No. of bitstreams: 1 Marcelo.pdf: 2394563 bytes, checksum: 31237f2a32525b07bfe3366d157e642b (MD5) Previous issue date: 2013-02-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Objective: Investigate the temporal evolution of the supply of trace elements, identifying trends in the historical concentration of the drainage basin of the Upper Paraná River Floodplain. Material and Methods: The corers extracted of the Patos Pond and the Garças Pond were sliced into uniform intervals of 2.2 and 2.0 cm respectively. Later the geochronological analysis was performed by the method radiochemical of isotope 210Pb. The quantification of element Mercury was performed with the equipment LUMEX. While the others trace elements were quantified by flame atomic absorption spectrometry, opening following the Method USEPA 3050B. Results: The sedimentation rate of the Garças Pond is 7.7 mm year-1 (2.66 kg m-2 year-1) and of the Patos Pond is 6.0 mm year-1 (1.94 kg m-2 year-1). Conclusion: The sediments of the Patos Pond and the Garças Pond have concentrations of trace elements similar to the background. The main factor that regulates the supply of trace elements in the Upper Paraná River Floodplain is the flood pulses, which can be magnified by the El Niño phenomenon. The burning of cane sugar, increased agriculture, urbanization and release of effluents from steel mills contributed to the increase in the concentration of some trace elements. While the adsorption by macrophytes and process oligotrophication caused by damss upstream of the floodplain, resulted in the reduction of the concentration of other elements / Objetivo: Investigar a evolução temporal do fornecimento de elementos-traço, identificando tendências na concentração histórica da bacia de drenagem da Planície Aluvial do Alto Rio Paraná. Material e Método: Os corers extraídos da Lagoa dos Patos e na Lagoa das Garças foram fatiados em intervalos uniformes de 2,2 e 2,0 cm respectivamente. Posteriormente foi realizada a análise geocronológica pelo método radioquímico do isótopo 210Pb. A quantificação do elemento Mercúrio foi realizada com o equipamento LUMEX. Enquanto os demais elementos-traço foram quantificados por meio de absorção atômica de chama, com abertura seguindo o método USEPA 3050B. Resultados: A taxa de sedimentação da Lagoa das Garças é de 7,7 mm ano-1 (2,66 kg m-2 ano-1) e da Lagoa dos Patos é de 6,0 mm ano-1 (1,94 kg m-2 ano-1). Conclusão: Os sedimentos das Lagoas dos Patos e da Lagoa das Garças possuem concentrações de elementos-traço semelhantes aos valores de referência. O principal fator que regula o fornecimento de elementos-traço na planície aluvial do Alto Rio Paraná são os pulsos de inundação, que podem ser magnificados pelo fenômeno climático El Niño. A queima da cana-de-açúcar, aumento da agropecuária, urbanização e lançamento de efluentes de siderúrgicas contribuíram para o aumento da concentração de alguns elementos-traço. Enquanto a adsorção por macrofitas aquáticas e o processo de oligotrofização, causado pelas barragens a montante da planície aluvial, acarretaram na redução da concentração de outros elementos

O presente estudo visou reconstruir o histórico de impactos antrópicos na bacia de drenagem do Lago das Garças durante o século XX por meio da deposição de contaminantes no compartimento sedimentar. O Lago das Garças está localizado em uma unidade de conservação, Parque Estadual das Fontes do Ipiranga (PEFI), inserida em área altamente povoada e urbanizada da cidade de São Paulo. Dois testemunhos de sedimento (LG05-03 e LG05-04, com 70 cm e 65 cm, respectivamente) foram amostrados mediante auxílio de mergulhadores no ponto mais profundo do reservatório, sendo, posteriormente, fatiados a cada 1 cm. Em LG05-03 foram quantificadas as distribuições verticais de carbono orgânico total (COT), nutrientes totais (NT e PT), hidrocarbonetos policíclicos aromáticos (HPA), hidrocarbonetos alifáticos (n-alcanos), bem como foi feita a classificação granulométrica. Em LG05-04 foi determinada a deposição de metais pesados (Co, Cr, Cu, Fe, Mn, Ni, Pb e Zn) e a geocronologia através do isótopo radioativo \'ANTPOT. 210 Pb\', usando o modelo CIC (Constant Initial Concentration). Os dados foram analisados por meio de análises estatísticas multivariadas (ACP: Análise de Componentes Principais). Com base nas tendências dos dados e na ACP, foi possível estabelecer três fases principais: Fase I: 64-43 cm (~1894-1975): caracterizada por baixas concentrações de nutrientes e contaminantes, sendo possível recuperar níveis préindustriais destes compostos, propostos como valores de referência regionais. Ainda, com base na razão C/N e em razões entre n-alcanos, notou-se, nesta fase o predomínio de aporte de matéria orgânica de origem alóctone; Fase II: 43-26 cm (~1975-1990): aumento abrupto das concentrações de metais pesados e HPA traçadores de veículos automotores, marcando o aumento da poluição atmosférica devido ao grande crescimento econômico do município e maior circulação de veículos na região. Ainda, foi observado aumento gradual das concentrações de NT e PT, atribuídos aos despejos de esgotos não tratados oriundos da Secretaria de Agricultura e Abastecimento e da Fundação Parque Zoológico; Fase III: 26-0 cm (~1990-2005): aumento mais acentuado das concentrações de nutrientes devido aos despejos de esgotos, acarretando em maior eutrofia do sistema, registrada pelo perfil do n-\'C IND.17\'. Pico das concentrações de HPA traçadores do uso de carvão mineral associado às atividades de uma siderúrgica vizinha (Siderúrgica J.L. Alipeti), bem como queda das concentrações destes traçadores coincidindo com mudanças no processo industrial da empresa. Ainda nesta fase notaram-se aumentos expressivos dos teores e fluxos dos HPA traçadores de veículos automotores, corroborando o cenário de aumento vertiginoso da frota de veículos na última década. Desse modo, este estudo contribuiu com o cenário nacional em termos de manejo de bacias hidrográficas urbanas, incluindo registros desde a época pré-revolução industrial no Brasil (~1894) até os dias atuais, demonstrando o potencial do uso de testemunhos lacustres no resgate de informações relativas à contaminação de ecossistemas aquáticos associadas às atividades antropogênicas. / Present study aimed to reconstruct the human impact history on the Garças Lake Drainage Basin during the 20th Century based on contaminants deposition on the lacustrine sediment. Garças Lake is located in a preservation area, the Parque Estadual das Fontes do Ipiranga (PEFI), located in a highly populated urban area within the city of São Paulo. Two sediment cores (LG05-03 and LG05-04, 70 cm and 65 cm long) were sampled by divers at the deepest site of the lake, which were sliced at 1 cm intervals. Information for LG05-03 included total organic carbon (TOC), total nutrients (TN and TP), polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons (n-alkanes) and grain size vertical distributions. Deposition of heavy metals (Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and the geocronology by \'ANTPOT. 210 Pb\', using CIC model (Constant Initial Concentration), were determined in LG05-04. Data were analyzed by multivariate statistic analysis (PCA, principal components analysis). Based on data trends and PCA, it was possible to recognized three main phases: Phase I: 64-43 cm (~1894-1975) characterized by low nutrients and contaminants concentrations, allowing retrieving preindustrial levels of these compounds, which are proposed as regional reference values. Besides, C/N ratio and n-alkanes ratios demonstrated aloctonous organic matter predominance; Phase II: 43-26 cm (~1975-1990) characterized by the abrupt increase of heavy metals and vehicular PAHs concentration, indicating the atmospheric pollution increase, due to the great economic rise experienced by the city of São Paulo over that time and the higher vehicles circulation in the region. Yet, it was observed a gradual increase in nutrient concentration attributed to the untreated sewage inputs from the São Paulo State Department of Agriculture and Provisioning headquarters and the city Zoo; Phase III: 26-0 cm (~1990-2005) characterized by a marked increase in nutrient concentration related to the untreated sewage inputs, leading to the increase of eutrophication, as registered by the n-\'C IND.17\' distribution. A peak of coal PAHs concentration was also noticed, related to a neighbor steel mill (J.L. Aliperti), followed by a subsequent decrease of these compounds, coincident with industrial procedures changes. Besides, there was an expressive increase in vehicular PAHs concentrations, corroborating the scenery of a drastic raise of vehicles in the last decade. The present study contributed to the national scenario towards urban drainage basin management. It included records since preindustrial time (~1894) up to the present, highlighting the potential use of lacustrine sediment on the retrieval of historical environmental changes of aquatic ecosystems and associated anthropogenic impacts.

No description available.