It has been hypothesized that authigenic carbonate minerals, formed within the pore spaces of marine siliciclastic formations during early diagenesis, may have had a substantial influence on the global carbon cycle, particularly in times of low oxygen in Earth history. According to this idea, alkalinity is generated via anaerobic organic matter degradation, resulting in carbonate oversaturation and the precipitation of low δ13C carbonate cements. If a substantial amount of 13C-depleted carbonate was sequestered in this authigenic sink, the δ13C of dissolved inorganic carbon (DIC) in the global ocean would be driven to more positive values without significant organic carbon burial - a signal which would be recorded in marine carbonates. Research presented herein tests this hypothesis from newly acquired lithostratigraphic and coupled stable carbon and oxygen isotope data of Upper Devonian limestone and black shale formations preserved within the Western Canada Sedimentary Basin. The Late Devonian includes a mass-extinction event, and is characterized by pervasive ocean anoxia and a dramatic reduction in platformal carbonate sediment deposition. As such, it has been hypothesized to represent an ideal time for the emergence of an active authigenic carbonate sink. Results show that both basinal shale (Besa River and Exshaw formations) and platform carbonates (Wabamun Group and its equivalents), record a δ13C signal that is within the expected range of Devonian seawater (3‰ to -2‰), signifying that precipitated authigenic carbonate had no influence on the isotopic composition of DIC. It was observed, however, that evaporitic depositional settings can accumulate carbonate sediment with low δ13C values (down to -8.4‰), potentially caused by local water column organic matter respiration during prolonged water-mass residence in a restricted marginal marine setting. If such depositional environments were globally pervasive, such as during during global sea-level lows, it is plausible that the carbon isotope mass balance would be affected. / Graduate / 2021-06-18

The decomposition of land snail shell is a complex process involving a number of factors and influences, including the characteristics of conchs themselves. In particular, it is the shell size with which the progress and the rate of degradation are tightly bound. Post-mortem changes begin with the loss of the original colour and, in the case of transparent species, by the opacification of the shell wall. Subsequently, the periostracum disruption and dissolution of calcium layers occur. However, this sequence may be reversed for some small species (e.g. Columella aspera, Nesovitrea hammonis). Animals mechanically destroy empty shells, humic acids from the substrate cause their artificial dyeing. Fungal mycelium or colonies of Streptomyces grow on the surface of the conchs. The plant roots are also involved in shell decomposition. While degradation of large shells starts with periostracum disruption and subsequent ostracal dissolution, periostracum of small shells persists even after dissolution of ostracal layers. The phenomenon is caused by high resistance of the periostraca of small species. In the case of large shells, periostracum has primarily a "building" function during shell formation, and sometimes it is flaking off already during the snail's life. For small species, it is an important part...

Cellulose nanocrystals (CNC) are great candidates for composite materials. The reasons why CNCs are such attractive materials for them are due to their great mechanical properties, high aspect ratio and low density. On the other hand, hydroxyapatite (HAp) is a kind of calcium phosphate and a main component of bones and teeth. The purpose of the present study is to make oriented nano-sized composites with CNC and HAp. Although some researchers carried out to make CNC composites with HAp for biomedical materials, nano-sized and oriented ones haven’t been achieved yet. Also, films made of CNC and other compounds are known to be transparent and have good oxygen permeability. Especially when CNCs’ direction is in parallel, they show high strength. However most previous researches dealt with particles or plate-like minerals in inorganic/CNC films, so there is no case that coated CNCs themselves were aligned in the films. Therefore fabrication of composite-oriented thin films is quite unique and it will be a potential step for bone-like hierarchical structure. In experiment, certain amount of CNC suspension with functional groups were put into revised simulated body fluid (r-SBF) solutions which were adjusted between pH 6.9-7.9 to make the molar ratio of calcium ion per functional groups on CNC surfaces between 30-230. The suspensions were put into the ultrasonic bath for 15 minutes and stirred in the thermostatic oven at 37 ⁰C for 1 hour. The process of ultrasound and stirring in oven was repeated 1-3 times depending on conditions. Precipitated products were collected with the centrifuge instrument and dried with the freeze dryer. Functional groups induced HAp’s nucleation and the HAp/CNC composites could be obtained under control of molar ratio of calcium ions per functional groups on CNC and pH. Morphology of the composites could be determined by pH and HAp content could be controlled between 25-75 wt% by initial molar ratio. The suspension having the composites synthesized in pH 7.9 with low initial molar ratio was dropped on superhydrophilic glass substrates. At the moment, the substrates were set with leans of 20 degrees. Then they were dried at 60 oC for 3 hours and transparent films containing 25-40 wt% of HAp were obtained. The transmittances of the films were more than 90 % and their thicknesses were 2.2-4.2 μm. The films were suggested to have oriented structure by polarization microscope when the shape of the composites were needle-like homogeneously and independent each other. From the results from SEM, they were aligned longitudinally at both ends of the film and laterally at the upper middle part of the films. It is considered that controlling drying direction influenced on the orientation. The current study should become a promising step to build up a bone-like hierarchical structure artificially.

Biomass combustion can be seen as CO2 neutral, thereby biomass combustion plants can have negative CO2 emissions if retrofitted with post combustion capture (PCC) technology using liquid absorbents. Monoethanolamine (MEA) has been used for carbon capture in coal combustion plants but are not suitable for use in biomass combustion plants due to corrosion and high solvent regeneration cost. Instead, the hot potassium carbonate (HPC) process using potassium carbonate (K2CO3) as absorbent show better attributes in these aspects. Although, K2CO3 has slow reaction kinetics with CO2 which need to be improved using promoters. Piperazine is the most tested promoter but are hazardous to humans. Recent research has revealed promising alternatives, among these different amino acid salts such as glycine, proline, and isonipecotic acid which are chemically benign. Biomass flue gas composition vary depending on the biomass fuel characteristics. How this affects the degradation and potential formation of hazardous substances need to be studied further. Biomass combustion plants are generally equipped with flue gas condensation systems, making retrofitting more feasible due to increased system flexibility and energy recovery options. The operation costs of carbon capture and sequestration (CCS) in biomass combustion plants need to be monitored to optimize the plant revenue. To make implementation of HPC in biomass combustion plants a reality, piperazine should be used as promoter. Meanwhile, research should focus on improving the absorption rate in HPC process with more chemically safe promoters.

The carbonate radical anion CO3•- is a potent reactive oxygen species (ROS) produced in vivo through enzymatic one-electron oxidation of bicarbonate or, mostly, via the reaction of CO2 with peroxynitrite. Due to the vitally essential role of the carbon dioxide/bicarbonate buffer system in regulation of physiological pH, CO3•- is arguably one of the most important ROS in biological systems. So far, the studies of reactions of CO3•- with DNA have been focused on the pathways initiated by oxidation of guanines in DNA. In this study, low-molecular products of attack of CO3•- on the sugar-phosphate backbone in vitro were analyzed by reversed phase HPLC. The selectivity of damage in double-stranded DNA (dsDNA) was found to follow the same pattern C4′ > C1′ > C5′ for both CO3•- and the hydroxyl radical, though the relative contribution of the C1′ damage induced by CO3•- is substantially higher. In single-stranded DNA (ssDNA) oxidation at C1′ by CO3•- prevails over all other sugar damages. An approximately 2000-fold preference for 8-oxoguanine (8oxoG) formation over sugar damage found in our study identifies CO3•- primarily as a one-electron oxidant with fairly low reactivity toward the sugar-phosphate backbone.

The carbonate saturometer method developed by Weyl (1961) was studied in respect to the effect of several variables on the solubility of carbonates. The solubility of three solid carbonate materials was measured in four different salt solutions, at four ionic strengths, and at two different temperatures . The solids studied included: calcite, dolomite, and a calcareous soil. It was found that the three solid carbonate materials varied in solubility from a low in the soil carbonates to a high in dolomite. Increasing the ionic strength of the solution increased the solubility of most of the solid carbonate materials. By decreasing the temperature, the solubility was increased. When S04- was present in solution, the solubility of both calcium carbonate and dolomite increased. When Mg++ was present in solution the solubility of calcium carbonate was increased more than was the solubility of dolomite.

This dissertation explores the influence of the environment on the lateral spatial patterning of facies in modern isolated carbonate platforms through six studies. The first study describes the creation of a database of benthic habitat and bathymetric maps derived from multispectral satellite imagery and the field data used calibrate and validate the mapping algorithms. The second study develops and assesses a new approach for remotely-deriving water depth from multispectral satellite imagery without the need for ground-truth information. The third study identifies a criterion for distinguishing between facies belts and mosaics and deploys the criterion to investigate the co-occurrence of these arrangements within modern carbonate depositional systems. The fourth study explores the geologic history of an isolated carbonate platform in the Bahamas, Cay Sal Bank, to understand why the lateral spatial pattering observed in this site differs from the patterns observed in neighboring platforms. The fifth study explores the distribution of carbonate facies in relation to wave energy and water depth for two detached ramps in the Red Sea, Ras Al-Qisbah and Al Wajh. The last study investigates the recovery of scleractinian communities along the coasts of two islands in the Galapagos archipelago, Darwin and Wennman (Wolf) Islands, following a large-scale disturbance in the 1980s. Together, these six studies provide new insight into the spatial patterning of facies within modern carbonate depositional systems and the influence of the environment on the observed arrangements.

Sediment on Cay Sal Bank (CSB) is characterized by its coarse-grain size, poor sorting, predominance of skeletal fragments, and relatively depleted d18O isotope values. CSB is an incipiently drowned platform in close proximity to the Great Bahama Bank (GBB), a carbonate platform which is not incipiently drowned and characterized by fine-grained, non-skeletal sediment. The GBB has locally well-developed oolitic grainstone facies and coral reef margins, which are both lacking on CSB. Platform-top water depths on the GBB are typically 10 m or less, but CSB depth ranges between 7 and 30 m. CSB is devoid of mud, whereas mud-supported depositional texture on GBB comprises 28% of the dataset. Dominant non-skeletal grains are grapestones and pelletoids, and the latter display evidence of micritization. Non-skeletal types on GBB are primarily grapestones and ooids. Surficial sediments from both platforms are primarily composed of aragonite, but high-magnesium calcite is slightly more prevalent on CSB. Similar to other incipiently drowned platforms in the Caribbean, CSB has been subject to rapid Holocene flooding. Common features between these three platforms are a thin sedimentary cover, a dominance of Halimeda plates, and micritized cryptocrystalline grains. Increased nutrient levels have been shown to be related to platform drowning as well as the reduction of coral and algal growth on Serranilla Bank, but rapid Holocene flooding has been more likely for CSB, and appears to be in the second of a three-stage drowning process, ultimately culminating in carbonate platform “turn off”, preventing further carbonate and reef development at the level of GBB.

This work reports the elucidation of the structure of a copolymer generated by the cross- catalyzed reactions of PF and pMDI prepolymers.  The electronic behavior of phenolic monomers as perturbed by alkali metal hydroxides in an aqueous environment was studied with 1H and 13C NMR.  Changes in electronic structure and thus reactivity were related to solvated ionic radius, solvent dielectric constant, and their effect on ion generated electric field strength. NMR chemical shifts were used to predict order of reactivity for phenolic model compounds with phenyl isocyanate with good success.  As predicted, 2-HMP hydroxymethyl groups were more reactive than 4-HMP in forming urethane bonds under neutral conditions and 2-HMP hydroxymethyl groups were more reactive than 4-HMP in forming urethane bonds under alkaline conditions. The structure of the reaction products of phenol, benzyl alcohol, 2-HMP, and 4-HMP with phenyl isocyanate were studied using 1H and 13C NMR under neutral organic and aqueous alkaline conditions.  Reactions in THF-d8 under neutral conditions, without catalyst, were relatively slow, resulting in residual monomer and the precipitation of 1,3-diphenyl urea from the carbamic acid reaction.  The reactions of phenol, 2-HMP, and 4-HMP in the presence of TEA catalyst favored the formation of phenyl urethanes (PU). Reactions with benzyl alcohol, 2-HMP, and 4-HMP in the presence of DBTL catalyst favored the formation of benzyl urethanes (BU).  Reactions of 2-HMP and 4-HMP led to formation of benzylphenyldiurethane (BPDU).  DBTL catalysts favored formation of BDPU strictly by a benzyl urethane pathway, while TEA favored its formation mostly via phenyl urethane, although some BU was also present.  Under aqueous alkaline conditions, 2-HMP was more reactive than 4-HMP, exhibiting an enhanced reactivity that was attributed to intramolecular hydrogen bonding and a resulting resonance stabilization of the phenolic aromatic ring. ATR-FTIR spectroscopic studies generated real time structural information for model compound reactions of the cross-catalyzed system, differentiating among reaction peaks generated by the carbamic acid reaction, PU and BU formation.  ATR-FTIR also permitted monitoring of propylene carbonate hydrolysis and accelerated alkaline PF resole condensation.  ATR-FTIR data also showed that the overall reaction stoichiometry between the PF and pMDI components drove copolymer formation.  Benzyl urethane formation predominated under balanced stoichiometric conditions in the presence of ammonium hydroxide, while phenyl urethane formation was favored in its absence.  Accelerated phenolic methylene bridge formation became more important when the PF component was in excess in the presence of sufficient accelerator.  A high percentage of free isocyanate was present in solid copolymer formed at ambient temperature. The combination of ammonium hydroxide and tin (II) chloride synergistically enhanced the reactivity of the materials, reducing the residual isocyanate. From 13C CP/MAS NMR of the copolymer, the presence of ammonium hydroxide and tin (II) chloride and the higher PF concentration resulted in substantial urethane formation.  Ammonium hydroxide favored formation of benzyl urethane from the 2-hydroxymethyl groups, while phenyl urethane formed in its absence.  The low alkalinity PF resole with ammonium hydroxide favored benzyl urethane formation.  Comparison of these results with the 13C NMR model compound reactions with phenyl isocyanate under alkaline conditions confirmed high and low alkalinity should favor phenyl and benzyl urethane formation respectively.  These cross catalyzed systems are tunable by formulation for type of co-polymer linkages, reactivity, and cost. / Ph. D.

The Sr/Ca ratios in calcium carbonate fossils are used by the paleooceanographic community to infer past environmental conditions, such as sea surface temperature and ocean chemistry. The processes of biogenic calcification that produce these chemical signatures are complex and not fully understood, however, and vital effects are known to affect the trace element composition of the CaCO₃ biomineral products. The recent discovery that calcifying organisms produce amorphous calcium carbonate (ACC) as an intermediate phase during the crystallization process calls into question whether this pathway to mineral formation affects trace element distributions in the final product. This non-classical mineralization process raises the question of whether the Sr/Ca ratios of the final products are dependent upon temperature. That is, what is the temperature dependence of Sr/Ca ratios in calcite produced via ACC compared to the measurements obtained from calcite grown by the classical process in laboratory experiments and from biogenic settings. The goal of this study is to determine the effects of solution chemistry and temperature on the Sr composition of ACC and resultant crystalline CaCO₃. Two types of experiments were designed: First, experiments were conducted to synthesize inorganic ACC in a batch reactor for a suite of selected chemical compositions and allowing this intermediate phase to transform into calcite in the reactant solution. In a second series of experiments, ACC was precipitated by a flow-through method to compare results to the batch reactor experiments. The experimental design focused on determining the Sr/Ca ratio and Sr distribution coefficients (KD, Sr) of the amorphous and final crystalline products. Mg/Ca ratios of 5/1 were found to suppress Sr uptake into ACC by a factor of 25% when the initial Sr solution had concentration of one millimolar. ICP-AES data collected across the 18° to 30°C range showed that the Sr/Ca ratio in both ACC and the resultant calcite was independent of temperature. Upon transformation, the Sr/Ca ratios of both the ACC and calcite product were found to be similar, showing that Sr/Ca ratios were independent of the transformation process. Analysis of the data determined KD, Sr values of 0.564(±0.006) for ACC and 0.466(±0.009) for the resultant calcite in the 18-30°C temperature range. The findings show that the Sr/Ca ratios of ACC and the transformed calcite are independent of temperature. However, the corresponding KD, Sr values exceed those reported for calcite grown by classical processes by an order of magnitude. The findings for the inorganic calcite yield KD, Sr values up to four times higher than those found in biogenic calcites. Because the findings of this study show that Sr/Ca is independent of temperature, this study calls into question whether previously reported Sr/Ca measurements in biogenic calcites should be revisited. It is plausible that biological factors have a significant influence on trace element incorporation into biogenic calcite. Vital effects, such as the influence of macromolecules during the ion uptake process, may regulate the apparent Sr/Ca versus temperature trends observed in marine paleontology. Higher KD, Sr values in marine calcifiers may indicate that organisms use the non-classical mineralization pathway in whole or in part. Future studies of trace element incorporation in calcifying species should consider the pathway to mineralization in tandem with interpretations of environmental controls on distribution coefficients. / Master of Science