Made available in DSpace on 2014-06-11T19:32:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-10Bitstream added on 2014-06-13T20:24:16Z : No. of bitstreams: 1 000737544.pdf: 4940477 bytes, checksum: 0101681bb21fe135e941ea5c67aaaadf (MD5) / A composição e a diversidade de comunidades microbianas podem ser usadas como indicadores da qualidade do solo, pois respondem rapidamente às mudanças ambientais. A intensificação da agricultura causa significante perda de diversidade, reduzindo a habilidade do ecossistema resistir a períodos de estresse e efeitos ambientais indesejáveis. Esta redução é mais evidente quando se trata de sistemas de monocultura, impactando os microrganismos e diversos invertebrados, e também reduz a capacidade de auto-regulação do solo. Assim, este trabalho tem como objetivo analisar a diversidade bacteriana em solos de floresta e em solos cultivados com canade- açúcar (Saccharum spp.) em diferentes períodos do ano que possa estar relacionada com a dinâmica dos ciclos biogeoquímicos, bem como um estudo comparativo entre diferentes áreas de cultivo e técnicas de sequenciamento. As amostras de solo foram coletadas no município de Santa Rita do Passa Quatro, SP. Amostras de DNA metagenômico de cada solo foram extraídas e construídas quatro bibliotecas com amplicons do gene 16S rRNA e quatro bibliotecas com amplicons da região V1 e V2 (Vi) do gene 16S rRNA. Um estudo comparativo com sequencias obtidas nas mesmas condições em outra área situada no município de Mococa, SP também foi analisado. Através dos dados obtidos, foi verificado que em solos de Floresta, independente do período do ano e área analisada, os filos bacterianos e a atividade dos organismos em relação aos ciclos biogeoquímicos, permaneceram praticamente inalterados. Este fato pode ser atribuído à estabilidade desde tipo de ecossistema, no qual existe ciclagem constante de nutrientes. Nas amostras de cana-de-açúcar, observou-se variação na frequência dos organismos encontrados em relação a diferentes coletas... / Microbial communities diversity and composition can be used as soil quality indicators, because respond quickly to environmental changes. Agriculture intensification causes significant loss of diversity, reducing the ability of the ecosystem to resist to periods of stress and undesirable environmental effects. This reduction is more evident when dealing with monoculture systems, impacting the microorganisms and several invertebrates, and also reduce the capacity of the soil self regulation. So, this study aims to analyze the bacterial diversity in forest soils and in soils cultivated with sugar cane (Saccharum spp.) in different periods of the year that can be related to biogeochemical cycles dynamic, as well as a comparative study between farming areas and sequencing techniques. Metagenomic DNA samples of each soil were extracted and built four libraries with gene 16S rRNA amplicons and four libraries with amplicons from gene 16S rRNA region Vi. A comparative study with obtained sequences in same conditions in another area situated in the municipality of Mococa, SP was also analyzed. Through the obtained data, it was found that in forest soils, regardless of the period of year and the area analyzed, bacterial phyla and organisms’ activity in relation to biogeochemical cycles, remained practically unchanged. This fact can be assigned to this type of ecosystem stability, in which there is a constant nutrients cycling. In soil samples cultivated with sugar cane, was observed variation in organisms frequency found in relation to different collections...

Made available in DSpace on 2014-06-11T19:32:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-13Bitstream added on 2014-06-13T19:03:35Z : No. of bitstreams: 1 000737578.pdf: 3803187 bytes, checksum: b8c4f772c3838e4786b19e09a8dc45b5 (MD5) / Os manguezais apresentam características que os diferenciam dos demais ecossistemas. O objetivo deste trabalho foi estudar os grupos microbianos (bactérias totais, esporuladas, Gram-negativas, actinobactérias, nitrificantes, desnitrificantes e fungos), as atividades metabólicas de bactérias e fungos, as atividades microbianas relacionadas ao ciclo do C, N, P (atividade respiratória, da desidrogenase, amonificante, nitrificante, da urease, da protease, solubilizadora de fosfato e da fosfatase ácida), além das análises químico-físicas (umidade, matéria orgânica, carbono orgânico total, carbono solúvel, carboidratos totais, fracionamento do fósforo, pH e salinidade) do solo de manguezal e compará-las com os de floresta e restinga. As amostras de solos foram coletadas durante o verão e o inverno, nas profundidades de 0 – 2 cm, 2 – 5 cm e 5 – 10 cm. Os micro-organismos isolados foram testados quanto à habilidade de produzir amilase, fosfatase ácida e/ou solubilizar fosfato inorgânico. Os resultados foram interpretados com análise estatística univariada. Excetuando os fungos totais, as contagens dos demais grupos microbianos decresceram significativamente (p < 0,05) na seguinte ordem: floresta > manguezal > restinga. As populações de actinobactérias predominaram no solo de floresta, porém foram semelhantes (p < 0,05) nos solos de manguezal e de restinga. O número das bactérias desnitrificantes foi similar nos solos de floresta e de manguezal e maior que o do solo de restinga. As contagens dos micro-organismos decresceram significativamente 11 e 21% da camada superficial para a 2 – 5 cm e 5 – 10 cm, porém as desnitrificantes aumentaram 44 e 166%. Enquanto o número de bactérias totais, esporuladas, Gram-negativas, nitrificantes e desnitrificantes decresceu (p < 0,05) 32% em média do verão para o inverno, o das actinobactérias permaneceu invariável e dos fungos aumentou 29%... / Mangroves has characteristics that differentiate them from other ecosystems. The objective of this study was to evaluate the frequency of microbial groups (total, sporulating, Gram-negative, actinomycetes, nitrifying, denitrifying bacteria and fungi), the bacteria and fungi metabolic activities, microbial activities related to the cycle of C, N, P (respiration, dehydrogenase, ammonium-oxidizing, urease, protease, solubilizing phosphate and acid phosphatase activities), and chemical-physical analysis (moisture, organic matter, total organic carbon, soluble carbon, carbohydrates, fractionation phosphorus, pH and salinity) from mangrove soil, comparing them with the restinga and forest soils. Soil samples were collected during the summer and winter, at depths of 0 – 2 cm, 2 – 5 cm and 5 - 10 cm. The microorganisms isolated were tested for their ability to produce amylase, acid phosphatase and/or solubilize inorganic phosphate. Results were interpreted with univariate statistical analysis. Except fungi total scores of other microbial groups decreased significantly (p < 0.05) in the following order: forest > mangrove > restinga. Populations of actinomycetes predominated in the forest soil, but were similar (p < 0.05) in mangrove soils and restinga. The denitrifying bacteria number was similar in forest and mangrove soil and higher than restinga soils. The microorganism counts decreased significantly 11 and 21% the surface layer for 2 - 5 cm and 5 - 10 cm, however, denitrifying increased 44 and 166%. While total number, sporulating, Gram-negative, nitrifying and denitrifying bacteria decreased (p < 0.05), on average 32% from summer to winter, actinomycetes remained unchanged and fungi increased 29%...

Orientadora: Lúcia Maria Carareto Alves / Banca: Antonio Carlos Monteiro / Banca: Haroldo Alves Pereira Júnior / Banca: Luciano Takeshi Kishi / Banca: Mariana Carina Frigieri Salaro / Resumo: A composição e a diversidade de comunidades microbianas podem ser usadas como indicadores da qualidade do solo, pois respondem rapidamente às mudanças ambientais. A intensificação da agricultura causa significante perda de diversidade, reduzindo a habilidade do ecossistema resistir a períodos de estresse e efeitos ambientais indesejáveis. Esta redução é mais evidente quando se trata de sistemas de monocultura, impactando os microrganismos e diversos invertebrados, e também reduz a capacidade de auto-regulação do solo. Assim, este trabalho tem como objetivo analisar a diversidade bacteriana em solos de floresta e em solos cultivados com canade- açúcar (Saccharum spp.) em diferentes períodos do ano que possa estar relacionada com a dinâmica dos ciclos biogeoquímicos, bem como um estudo comparativo entre diferentes áreas de cultivo e técnicas de sequenciamento. As amostras de solo foram coletadas no município de Santa Rita do Passa Quatro, SP. Amostras de DNA metagenômico de cada solo foram extraídas e construídas quatro bibliotecas com amplicons do gene 16S rRNA e quatro bibliotecas com amplicons da região V1 e V2 (Vi) do gene 16S rRNA. Um estudo comparativo com sequencias obtidas nas mesmas condições em outra área situada no município de Mococa, SP também foi analisado. Através dos dados obtidos, foi verificado que em solos de Floresta, independente do período do ano e área analisada, os filos bacterianos e a atividade dos organismos em relação aos ciclos biogeoquímicos, permaneceram praticamente inalterados. Este fato pode ser atribuído à estabilidade desde tipo de ecossistema, no qual existe ciclagem constante de nutrientes. Nas amostras de cana-de-açúcar, observou-se variação na frequência dos organismos encontrados em relação a diferentes coletas... / Abstract: Microbial communities diversity and composition can be used as soil quality indicators, because respond quickly to environmental changes. Agriculture intensification causes significant loss of diversity, reducing the ability of the ecosystem to resist to periods of stress and undesirable environmental effects. This reduction is more evident when dealing with monoculture systems, impacting the microorganisms and several invertebrates, and also reduce the capacity of the soil self regulation. So, this study aims to analyze the bacterial diversity in forest soils and in soils cultivated with sugar cane (Saccharum spp.) in different periods of the year that can be related to biogeochemical cycles dynamic, as well as a comparative study between farming areas and sequencing techniques. Metagenomic DNA samples of each soil were extracted and built four libraries with gene 16S rRNA amplicons and four libraries with amplicons from gene 16S rRNA region Vi. A comparative study with obtained sequences in same conditions in another area situated in the municipality of Mococa, SP was also analyzed. Through the obtained data, it was found that in forest soils, regardless of the period of year and the area analyzed, bacterial phyla and organisms' activity in relation to biogeochemical cycles, remained practically unchanged. This fact can be assigned to this type of ecosystem stability, in which there is a constant nutrients cycling. In soil samples cultivated with sugar cane, was observed variation in organisms frequency found in relation to different collections... / Doutor

Orientador: Ely Nahas / Banca: Marli de Fátima Fiori / Banca: Diva de Souza Andrade / Banca: José Eduardo Corá / Banca: Jackson Antônio Marcondes de Souza / Resumo: Os manguezais apresentam características que os diferenciam dos demais ecossistemas. O objetivo deste trabalho foi estudar os grupos microbianos (bactérias totais, esporuladas, Gram-negativas, actinobactérias, nitrificantes, desnitrificantes e fungos), as atividades metabólicas de bactérias e fungos, as atividades microbianas relacionadas ao ciclo do C, N, P (atividade respiratória, da desidrogenase, amonificante, nitrificante, da urease, da protease, solubilizadora de fosfato e da fosfatase ácida), além das análises químico-físicas (umidade, matéria orgânica, carbono orgânico total, carbono solúvel, carboidratos totais, fracionamento do fósforo, pH e salinidade) do solo de manguezal e compará-las com os de floresta e restinga. As amostras de solos foram coletadas durante o verão e o inverno, nas profundidades de 0 - 2 cm, 2 - 5 cm e 5 - 10 cm. Os micro-organismos isolados foram testados quanto à habilidade de produzir amilase, fosfatase ácida e/ou solubilizar fosfato inorgânico. Os resultados foram interpretados com análise estatística univariada. Excetuando os fungos totais, as contagens dos demais grupos microbianos decresceram significativamente (p < 0,05) na seguinte ordem: floresta > manguezal > restinga. As populações de actinobactérias predominaram no solo de floresta, porém foram semelhantes (p < 0,05) nos solos de manguezal e de restinga. O número das bactérias desnitrificantes foi similar nos solos de floresta e de manguezal e maior que o do solo de restinga. As contagens dos micro-organismos decresceram significativamente 11 e 21% da camada superficial para a 2 - 5 cm e 5 - 10 cm, porém as desnitrificantes aumentaram 44 e 166%. Enquanto o número de bactérias totais, esporuladas, Gram-negativas, nitrificantes e desnitrificantes decresceu (p < 0,05) 32% em média do verão para o inverno, o das actinobactérias permaneceu invariável e dos fungos aumentou 29%... / Abstract: Mangroves has characteristics that differentiate them from other ecosystems. The objective of this study was to evaluate the frequency of microbial groups (total, sporulating, Gram-negative, actinomycetes, nitrifying, denitrifying bacteria and fungi), the bacteria and fungi metabolic activities, microbial activities related to the cycle of C, N, P (respiration, dehydrogenase, ammonium-oxidizing, urease, protease, solubilizing phosphate and acid phosphatase activities), and chemical-physical analysis (moisture, organic matter, total organic carbon, soluble carbon, carbohydrates, fractionation phosphorus, pH and salinity) from mangrove soil, comparing them with the restinga and forest soils. Soil samples were collected during the summer and winter, at depths of 0 - 2 cm, 2 - 5 cm and 5 - 10 cm. The microorganisms isolated were tested for their ability to produce amylase, acid phosphatase and/or solubilize inorganic phosphate. Results were interpreted with univariate statistical analysis. Except fungi total scores of other microbial groups decreased significantly (p < 0.05) in the following order: forest > mangrove > restinga. Populations of actinomycetes predominated in the forest soil, but were similar (p < 0.05) in mangrove soils and restinga. The denitrifying bacteria number was similar in forest and mangrove soil and higher than restinga soils. The microorganism counts decreased significantly 11 and 21% the surface layer for 2 - 5 cm and 5 - 10 cm, however, denitrifying increased 44 and 166%. While total number, sporulating, Gram-negative, nitrifying and denitrifying bacteria decreased (p < 0.05), on average 32% from summer to winter, actinomycetes remained unchanged and fungi increased 29%... / Doutor

Submitted by AYLAN KENER MENEGHINE (aylankm@gmail.com) on 2017-01-10T01:14:02Z No. of bitstreams: 1 Tese_Aylan_Kener_Meneghine.pdf: 2274173 bytes, checksum: 058fc5159e6fa34a7c970ce061ce70c5 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-01-12T19:08:55Z (GMT) No. of bitstreams: 1 meneghine_ak_dr_jabo.pdf: 2274173 bytes, checksum: 058fc5159e6fa34a7c970ce061ce70c5 (MD5) / Made available in DSpace on 2017-01-12T19:08:55Z (GMT). No. of bitstreams: 1 meneghine_ak_dr_jabo.pdf: 2274173 bytes, checksum: 058fc5159e6fa34a7c970ce061ce70c5 (MD5) Previous issue date: 2016-12-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O composto orgânico produzido a partir de carcaças, resíduos animais e vegetais é uma alternativa viável para a substituição total ou parcial dos fertilizantes minerais utilizados na atualidade. No processo de compostagem participam diferentes populações microbianas, e com isso o composto torna-se um sistema rico para utilização como fertilizante no solo, complementando assim as necessidades nutricionais e microbianas do meio ambiente. Entretanto, há poucos trabalhos envolvendo análise da diversidade bacteriana em solos sob uso de composto orgânico feito a partir de carcaças, e também pouco se conhece sobre o impacto ambiental do uso agrícola de composto orgânico na qualidade da água. Existe também a questão se há influência da água utilizada para irrigação na qualidade do solo. O objetivo central desse trabalho foi analisar a diversidade bacteriana e perfil funcional de um solo de horta e da água de um córrego utilizada para irrigação. E como objetivo secundário, através do isolamento de bactérias da água verificar o potencial biotecnológico de produção e uso de exopolissacarídeo como bioemulsificante de óleo e hidrocarbonetos. As amostras de solo e água utilizadas nesse trabalho foram coletadas na área do departamento rural da Fundação Parque Zoológico de São Paulo, em setembro de 2014. Todo material coletado foi transportado até o Laboratório de Bioquímica de Micro-organismos e de Plantas, onde realizou-se a extração de DNA total e sequenciamento através de tecnologia Ion Proton (Life Technologies), isolamento bacteriano, produção e aplicação de exopolissacarídeo como bioemulsificante. Ao analisar o DNA metagenômico observou-se que tanto na água quanto no solo há uma abundância de bactérias encontradas normalmente em áreas agrícolas sob influência de composto orgânico feito a partir de outras fontes. Verificou-se também, através da análise dos genes relacionados com os ciclos biogeoquímicos, abundância de genes do processo de desnitrificação na amostra de solo. Além de se observar que na análise da estrutura taxonômica dos ciclos biogeoquímicos, não há bactérias em comum entre as amostras de solo e água com do composto orgânico. Porém ao avaliar o perfil funcional total da água, solo e outros dez metagenomas, através de uma análise de agrupamento hierárquico, notou-se que a água causa maior influência no solo do que o próprio composto orgânico. Com relação ao isolamento bacteriano, foi possível isolar a bactéria Sphingomonas sp., sendo que o isolado identificado demonstrou produzir grande quantidade de exopolissacarídeo (EPS). O EPS formou emulsões estáveis após 24 horas e 168 horas. Além disso o EPS foi um melhor agente emulsificante para hexano e querosene dentre todos os óleos analisados. Os resultados mostraram contribuição significativa com relação ao potencial do EPS como agente bioemulsificante que aumentaria a degradação de hidrocarbonetos e efeitos de emulsificação em biotecnologia ambiental. / The organic compost produced from carcasses, animal and vegetable waste is a viable alternative to full or partial replacement of mineral fertilizers used nowadays. In the composting process there are involved different microbial populations, and the compost becomes a rich system for use as a fertilizer in the soil, thereby supplementing the nutritional and microbial requirements of the medium. However, there are few studies involving the analysis of bacterial diversity in soil under use of organic compost made from carcasses, and also little is known about the environmental impact of agricultural use of organic compost in water quality. Furthermore, there is also the question of whether there is influence of the water used for irrigation on soil quality. Because of these questions, the central objective of this study was to analyze the bacterial diversity and functional profile of a soil from vegetable garden and freshwater used for irrigation from a local stream. As a secondary objective, we aimed to verify the production and biotechnology potential of a bacterial exopolysaccharide as oil and hydrocarbons bioemulsifier. Soil and freshwater samples used in this study were collected at rural department of the Zoo Foundation Park of São Paulo, in September 2014. All material collected was transported to the Laboratório de Bioquímica de Micro-organismos e de Plantas where we proceeded with the total DNA extraction experiments, sequencing through Ion Proton technology (Life Technologies), bacterial isolation, production and application of exopolysaccharide as bioemulsifier. By analyzing the metagenomic DNA it was observed that both freshwater and soil were plenty of bacterial communities normally found in agricultural areas under influence of organic amendments. Through the analysis of genes related to biogeochemical cycles, it was found abundance of genes about denitrification process in the soil sample. Also it can be noted by the analysis of the taxonomic structure of biogeochemical cycles, there was no bacteria shared between soil and freshwater samples with the organic compost. But when evaluating the functional profile of freshwater, soil and other ten metagenomes, we observed that freshwater causes greater influence on the soil than the organic compost. Regarding the bacterial isolation, it was possible to identify the bacteria Sphingomonas sp., and it has been shown to produce large amount of exopolysaccharide (EPS). The EPS has shown stability in its emulsions after 24 hours and 168 hours. Additionally, it’s a better emulsifying agent for hexane and kerosene among other oils analysed. Furthermore, our findings promoted significant contribution by showing EPS potential as a bioemulsifier agent that would enhance hydrocarbon degradation and emulsification effects in environmental biotechnology.

Zinc (Zn) and cadmium (Cd) have nutrient-type vertical distributions reflecting control driven by biological uptake in surface waters and remineralization of sinking biogenic particles at depth. Both metals show strong correlations with major algal nutrients (Cd with phosphate (PO43-) and Zn with silicic acid (Si)) in the world ocean. Through their roles as micronutrients and toxins to marine phytoplankton, Zn and Cd can influence surface biological community composition. Preserved Zn and Cd records have been employed as proxies to gain insight into nutrient distributions, circulation, and organic carbon export in the paleocean. A thorough and mechanistic understanding of the biogeochemical cycling of Zn and Cd is necessary for accurate paleoceanographic reconstructions as well as predicting alterations in metal supply to the modern surface ocean and its impacts on primary productivity due to oceanic changes. My dissertation aims to further this understanding through an investigation of Zn and Cd distributions in the subarctic northeast Pacific through samples collected along the Line P transect. A major focus of this dissertation was identifying and characterizing depletions of metals in O2-depleted waters relative to global and basin scale metal:macronutrient correlations. Dissolved Cd profiles from the subarctic northeast Pacific and the eastern North Atlantic show a deficit of Cd relative to regional Cd:PO43- relationships. Particulate Cd and Cd stable isotopes (ε112/110Cd) from low-O2 North Atlantic waters and published sedimentary data from the subarctic northeast Pacific point to a previously undocumented water-column metal removal process acting in O2-depleted waters. Metal sulphide formation, likely in association with particulate microenvironments, can explain the observed deficits. Other metals with similar sulphide coordination chemistry should also form metal sulphides if this process is occurring. Dissolved Zn from Line P showed distributions and Zn:Si relationships that are consistent with the removal of metal in O2-depleted waters through sulphide formation. A first order approximation of the Cd deficit suggests that sulphide formation may be an important sink term in the global Cd cycle. Surface and upper nutricline Zn:Si and Cd:PO43- relationships in the chronically iron (Fe)-limited subarctic northeast Pacific showed distinct trends, which differ from those seen in Fe-replete regions. Distributions suggest the formation of surface biogenic particles with high Cd:PO43- and Zn:Si, leaving surface waters depleted in metals relative to macronutrients and resulting in high metal:macronutrient ratios in the nutricline as these particles sink and are remineralized. This is consistent with understandings of phytoplankton physiology and uptake of divalent metals under Fe-limitation, and corresponds well with global data for dissolved Cd:PO43- patterns in Fe-limited regions. Subsurface high Cd:PO43- and Zn:Si may also be influenced by the advection of water enriched in trace metals. The distinct shallow remineralization horizon observed for Zn compared to Si in the subarctic northeast Pacific by this and previous work presents a fundamentally different distribution than observed in global Zn:Si compilations. Directed sampling in the subarctic northeast Pacific should help elucidate the mechanism behind the oceanographically distinct distributions in this basin. Dissolved ε112/110Cd from Line P demonstrates a remarkably uniform subarctic northeast Pacific deepwater reflecting an advected source signal. Particulate ε112/110Cd samples show an active Cd cycle, which is not imprinted upon the dissolved phase. Particulate ε112/110Cd from 200-600 m depth is among the lightest ε112/110Cd ever reported for natural telluric samples. This may be an important sink for light Cd in the global ocean, which at present is heavy with respect to known sources. Line P surface waters with very low Cd concentrations are not accurately represented by a closed-system Rayleigh model, which can describe ε112/110Cd in the Southern Ocean. This suggests spatially and/or temporally variable surface ε112/110Cd fractionation. A large difference is observed in reported dissolved ε112/110Cd at very low Cd concentrations between different instrumentations. An intercalibration is necessary to determine if this is an analytical artefact or reflects real oceanic variability. / Graduate

Magister Scientiae - MSc / In areas of transported overburden there is frequently a weak relationship between soil and the underlying mineralized bedrock. Vegetation has the capability to absorb metals from the underlying substrate via its extensive root systems. These metals are translocated to the various organs of the plant such as leaves, twigs bark and roots without negatively impacting on the normal functioning of the plant. The analysis of the vegetation may therefore be used to locate deeply buried mineral targets. The main focus of this investigation was to determine the suitability of A. karroo and B. albitrunca for biogeochemical prospecting for gold in the Blue Dot Mine area. The appraisal of the suitability for both plant species requires an understanding of element absorption and distribution patterns in relation to variable composition of bedrock and associated underlying gold mineralization. / South Africa

No description available.

No description available.

Evidence of three glaciations in Paleoproterozoic successions of North America and at least one on three other continents, suggests that these glaciations were of global extent. In common with the Neoproterozoic record, carbonates cap the glacials. However, the relationship between biogeochemical cycling of carbon and ice ages has not been fully appreciated. This research involved the sedimentology and isotope stratigraphy of carbonates and shales in Paleoproterozoic glacially-influenced successions of Wyoming and South Africa. Carbonates of the Vagner Formation cap the middle of three diamictites in the Snowy Pass Supergroup, Medicine Bow Mountains, WY. The Duitschland Formation occurs between two glacial horizons in South Africa. Limestones retain negative d13C values for over 60 m in the Vagner Formation, and for over 100 m in the lower part of the Duitschland Formation. Isotope compositions of TOC from the lower part of the Duitschland Formation reveal pronounced enrichment resulting in significantly lower fractionation between organic and inorganic carbon. This is similar to enrichment noted in Neoproterozoic cap carbonates. Combined with strongly positive carbon isotope compositions in upper Duitschland carbonates, the data from the Vagner Formation underscores strongly positive-to-negative carbon isotope trends bracketing Paleoproterozoic glaciations. These trends mimic those noted in Neoproterozoic glacial successions and possibly indicate a recurrence of global glaciations. The Slaughterhouse and Nash Fork formations significantly postdate the glacial epoch. Both the lower part of the Nash Fork Formation, Medicine Bow Mountains and the Slaughterhouse Formation, Sierra Madre contains carbonates with 13C-enrichment >+6â ° and locally up to +28%, whereas carbonates higher in the Nash Fork Formation have d13C values between 0 and 2.5%. This dramatic change in the composition of the Paleoproterozoic ocean is constrained at ca. 2.1 Ga (Karhu, 1993). Carbonates in the Rawhide Canyon section of the Whalen Group in the Hartville Uplift (the easternmost exposure of the Wyoming Craton) display δ13C values up to +8.2% suggesting correlation with the Slaughterhouse and Nash Fork formations and their deposition on continuous carbonate platform along the margin of the Wyoming Craton. These data support an open-marine, and therefore a global origin for the ca. 2.2-2.1 Ga carbon isotope excursion. / Ph. D.