Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1977. / Bibliography: leaves 138-146. / Microfiche. / x, 146 leaves ill

The reef corals Pocillopora damicornis and Montipora verrucosa were cultured under various controlled temperatures and light conditions at Ulupau Head Microcosm facility. The skeletal carbonate deposited under different experimental regimes was analyzed for 13C and 18O. Coral skeletal 013C values varied with light dose and correlated with changes in zooxanthellar pigment. The o13C value of skeletal aragonite seems to be controlled by oxidation of photosynthetically produced organic matter. Functionally significant relationships between coral skeletal o18O values and temperature have been determined. The temperature coefficients of the o18O values (-4.20) are the same as the first order coefficient in the equilibrium paleotemperature equation, but the o18O values have species-specific offsets from equilibrium. These offsets may be attributed to the activity of the coral's zooxanthellae. Based upon the results of this study a model of coral skeletal isotopic incorporation is presented. / Typescript. Thesis (M. S.)--University of Hawaii at Manoa, 1979. Bibliography: leaves 94-102.

Afforestation and reforestation programs utilizing available fields for biofuel production, carbon sequestration, and other uses linked to climate change are looking to tree physiologists to identify species and genotypes best-suited to their purposes. The ideal poplar genotype for use in Canadian programs would be drought-resistant, cold-climate adapted, and fast-growing, thus requiring an understanding of links between a variety of physiological traits linked to growth and productivity. This study examined the basis for variations in water-use efficiency within four selected populations of Populus trichocarpa and Populus balsamifera (2 provenances each). Each species included both a northern and a southern provenance. Correlations between water-use efficiency, nitrogen-use efficiency, ¹³C/¹²C isotope ratio, stomatal conductance, and overall productivity were evaluated. Gas exchange variables measured included net photosynthesis, transpiration rate, stomatal conductance, and intercellular CO₂ content. Water-use efficiency and ¹³C content across all genotypes were highly correlated. Results suggested that variation in water-use efficiency was primarily related to variation in stomatal conductance across all genotypes. Whereas differences in net photosynthesis in this study were not significant between species, P. balsamifera did reveal a higher average stem volume overall. Although variation in stomatal conductance was the major determinant of differences in water-use efficiency, positive correlations were found between ¹³C isotope abundance and net photosynthesis in both P. balsamifera provenances. In this regard, results for the northern P. balsamifera provenance are the most consistent across all gas-exchange and growth trait correlations, in terms of meeting expectations for sink-driven water-use efficiency. The findings in this study suggest the possibility of identifying poplar genotypes with an absence of trade-off between water-use efficiency and nitrogen-use efficiency, notably among genotypes from the northern P. balsamifera provenance, near Gillam.

Thesis (Ph. D.)--Lehigh University, 2006. / Includes vita. Includes bibliographical references (leaves 187-192).

Traditionally, sedimentation at active plate margins is thought to be dominantly controlled by tectonism, with any climatic cyclicity being overprinted. Since the early Miocene, Cyprus has been situated above an active subduction zone, which has strongly influenced the regional tectonics. Global climate change also occurred during the Miocene marking a transition from relative global warmth of the early-Miocene to the Neogene 'icehouse world'. Cyprus has extensive outcrops of Miocene to Pleistocene deep water sediments and provides an ideal setting to test the magnitude of climatic signals in tectonically active areas, and thus deduce the relative roles of climate and tectonics on sedimentation. Detailed sedimentary logging and biostratigraphical dating of the Miocene-age pelagic Pakhna Formation reveals that the formation can be divided into depositional sequences,bounded by hard grounds or erosion surfaces, and contains a distinct pattern of marl-chalk couplets. These sequences correlate, within the constraints of biostratigraphy to European and New Jersey Margin sequence chronostratigraphy. Three smaller scales of cyclicity are identified by stratigraphic time series analysis, and are likely to correspond to the 100 kyr, 41ky and ~20 ky Milankovitch cycles. Stable oxygen and carbon isotope analysis on pelagicforaminifera indicate the following climatic influences; (1) chalk-marl couplets probably record climatically controlled supply of terrigenous material; (2) a strong link between 8¹⁸O maxima and sequence boundaries; and (3) the globally recognised 8¹³C Monterey ExcursionIS present. The increasing abundance of tectonically derived Troodos material partially masks the climatically controlled sedimentation in the Pakhna Formation south of the Troodos massif. Rapid Troodos uplift during the Pliocene-Pleistocene is demonstrated by the high abundance of ophiolite derived clasts in the Khirokitia-Psematismenos submarine fan-complex. Here,graphic logging, and biostratigraphy suggests that the six cycles observed are likely to correlate to cycles identified in European sequence chronostratigraphy, though higher frequency,climatic cyclicity is obscured by the overprint of tectonic activity.

M.Sc. / Please refer to full text to view abstract

Afforestation and reforestation programs utilizing available fields for biofuel production, carbon sequestration, and other uses linked to climate change are looking to tree physiologists to identify species and genotypes best-suited to their purposes. The ideal poplar genotype for use in Canadian programs would be drought-resistant, cold-climate adapted, and fast-growing, thus requiring an understanding of links between a variety of physiological traits linked to growth and productivity. This study examined the basis for variations in water-use efficiency within four selected populations of Populus trichocarpa and Populus balsamifera (2 provenances each). Each species included both a northern and a southern provenance. Correlations between water-use efficiency, nitrogen-use efficiency, ¹³C/¹²C isotope ratio, stomatal conductance, and overall productivity were evaluated. Gas exchange variables measured included net photosynthesis, transpiration rate, stomatal conductance, and intercellular CO₂ content. Water-use efficiency and ¹³C content across all genotypes were highly correlated. Results suggested that variation in water-use efficiency was primarily related to variation in stomatal conductance across all genotypes. Whereas differences in net photosynthesis in this study were not significant between species, P. balsamifera did reveal a higher average stem volume overall. Although variation in stomatal conductance was the major determinant of differences in water-use efficiency, positive correlations were found between ¹³C isotope abundance and net photosynthesis in both P. balsamifera provenances. In this regard, results for the northern P. balsamifera provenance are the most consistent across all gas-exchange and growth trait correlations, in terms of meeting expectations for sink-driven water-use efficiency. The findings in this study suggest the possibility of identifying poplar genotypes with an absence of trade-off between water-use efficiency and nitrogen-use efficiency, notably among genotypes from the northern P. balsamifera provenance, near Gillam. / Forestry, Faculty of / Graduate

An often overlooked connection between karst groundwater systems and surface water is spring flow reversal, the flow of river water into karst springs caused by changes in hydraulic gradient. Karst aquifers are subject to the intrusion of river water when the hydraulic head of a base level river is higher than the hydraulic head of a base level spring. When this occurs, the flow out of the spring reverses, allowing river water to enter base level conduits. River water thus becomes a source of recharge into karst basins, transporting both valuable nutrients and harmful contaminants into karst aquifers. The rapid recharge of meteoric water, brief groundwater residence times, and the interconnection of surface and subsurface waters through a variety of karst features necessitates studying groundwater and surface water in karst landscapes as a unified system. This study examines the influence of spring flow reversal on cave dissolution in a telogenetic karst aquifer in Mammoth Cave, Kentucky. Spring flow reversals in Mammoth Cave National Park (MCNP) were first recorded nearly one-hundred years ago, but a high-resolution study measuring the effects of spring flow reversals on dissolution in MCNP, or any other telogenetic karst system, had not been conducted until recently. In this study, high-resolution data were collected for pH, SpC, temperature, and stage, as well as weekly samples for major ion concentrations, alkalinity, and carbon isotopes, from June 2018 to December 2018. Surface water and groundwater data were used to quantify the complex hydrologic processes associated with the spring flow reversals, including seasonal changes in karst geochemistry and dissolution taking place between the Green River, River Styx Spring, and Echo River Spring. Data show distinct changes in geochemical parameters as flow reversals occur, with temperature being the principal indicator of flow direction change. During this study, all ten stable reverse flows coincided with increased discharge from the Green River Dam. The predominant drivers of dissolution in the River Styx and Echo River karst basins are storm events and seasonal changes in the hydrologic regime, rather than seasonal CO2 production, normal baseflow conditions, or stable reverse flow events. Estimated dissolution rates generally show that stable reverse flows contribute no more to dissolution than normal baseflow conditions – the highest amount of dissolution during a single stable reverse flow was only 0.003 mm. This is contrary to flow reversal studies in an eogenetic karst system in Florida, which estimated 3.4 mm of wall retreat during a single spring flow reversal. These contrasting results are likely due to significant differences in pH of river water, matrix porosity of the bedrock, basin morphology, and flow conditions.

This study consists of four major areas of research. First, the relationship between and was extended to Lrl nil homoallylic couplings and was used to determine the relative degree of puckering in a series of dihydroaromatic carboxylic acids. Second, the effect of coupling contributions transmitted through space were examined by theoretical calculations of the intermediate neglect of differential overlap finite perturbation theory type (INDO-FPT) including selective overlap reduction experiments to determine the sign and magnitude of the major through-space contributions and the effect of the orientation of the substituent upon the vicinal carbon3 carbon coupling. Third, the dependence of the J upon substituent orientation in norbornanes was empirically investigated by the synthesis of a series of lactones and cyclic ethers whose conformation was rigid and known. Fourth, a large number of norbornanes substituted with methyls in the 1, 3, and 7 position and a carbon-13 labeled substituent in the 2 position were synthesized and studied in order to obtain a variety of vicinal C-C couplings; all the NMR parameters for this series of compounds were determined while the carbon13 labeled substituent was varied from methyl to methylene to carbinol to aldehyde and to carboxylic acid.

The study consists of three major areas of research. First, the dihedral angle dependence of vicinal carbon-carbon coupling constants is determined for aliphatic and alicyclic carboxylic acids wherein the formal hybridization and substituents are held constant. Second, the magnitudes and relative signs of long-range carbon-carbon coupling constants in a. triple- 13 C-labeled system are determined and compared with carbon-proton and/or proton-proton coupling constants in geometrically similar compounds. Third, the effect of changes in hybridization on long-range carbon-carbon coupling constants is determined for the following three groups of molecules: olefins and saturated hydrocarbons, aliphatic carboxylic acids, and aromatic compounds. In all cases only closely related systems are compared in order to identify the effect of individual molecular parameters. Most importantly, the results indicate that carbon-carbon couplings do correlate in magnitude and sign with carbon-proton and proton-proton couplings in analogous molecular. frameworks. Thus, the coupling mechanisms are similar in all three types of coupling. In addition, the observed trends in long-range carbon-carbon couplings provide an unambiguous method for assigning carbon chemical shifts.