The technique of ligand-exchange was investigated as a possible method for the extraction and concentration of organic compounds dissolved in seawater. Cation-exchange resins in transition metal forms were used to extract carboxylate anions and amino-acids from dilute solution in synthetic seawater. The optimum conditions found from small-scale experiments were applied to the extraction of ¹⁴C-labelled amino-acids from natural seawater. This work demonstrated (1) the strong bonding of transition-metal ions., especially Fe(iii), to the chelating resin Dowex A-1 (2) the sorption of citrate, tartrate, glycine and glutamate by Dowex A-1 in Fe(iii) form (3) the sorption of glutamate and alanine by the same resin in Ni(NH₃)₃. and Cu(NH₃) form (4) the displacement of the organic ligands by inorganic reagents: 2M KH₂PO₄ in the case of Fe(iii) and 30% ammonia in the case of Ni(NH₃)₃ and Cu(NH₃) forms. It was concluded that the method is of marginal utility for the first-stage extraction of organic ligands from seawater. The relationship of the experimental results to tabulated Stability Constants of Transition-metal complexes with organic ligands is briefly discussed. / Science, Faculty of / Chemistry, Department of / Graduate

A method was developed for the determination of aluminum in sea water using oxine as a reagent. Extraction of aluminum oxinate by chloroform from acidic solution was impeded by the presence of fluoride in sea water. The fluoride Interference was less severe in basic solution and it was possible to extract aluminum oxinate from sea water at a pH of 8 with no loss of sensitivity due to the presence of fluoride. Iron and copper were complexed with cyanide in reducing solution and manganese oxinate was removed by extracting it from the chloroform into an aqueous acidic solution. Other interfering ions in sea water were present in amounts too small to be significant. The absorbancy of the aluminum oxinate complex was measured at 395 mμ and compared with a calibration curve. The aluminum concentration in sea water ranged from 2-42 μg./l. Values for coastal water were higher than for oceanic water. / Science, Faculty of / Chemistry, Department of / Graduate

The degree of chemical instability of pteridines (related to xanthopterin) and purines (related to uric acid) in seawater was studied with a view (i) to assess its role in the ecological turnover of these compounds in the marine environment, (ii) to define the integrity with which they may serve as nitrogen-source for growth of marine phytoplankters. Solutions of these compounds were incubated aseptically at 20-25°C with illumination from cool-white fluorescent lamps or in complete darkness and the chemical changes were monitored spectrophotometrically. Among the purines tested, uric acid showed slow degradation in darkness which was accelerated by light, while xanthine was degraded only by light. Adenine, guanine and hypoxanthine appeared to be stable. The pteridines tested included pterin (2-amino-4-hydroxy-pteridine), lumazine (2,4-dihydroxypteridine), and their following hydroxylated derivatives: 6-monohydroxyl (xanthopterin, oxylumazine), 7-monohydroxyl (isoxanthopterin), 6,7-dihydroxyl (leucopterin, dioxylumazine). In general, they showed the following order of chemical stability in seawater: 6,7-unsubstituted > 7-monohydroxyl > 6,7-dihydroxyl > 6-monohydroxyl. The studies were extended to investigate whether the instability was due to the pH or the salt composition of seawater and pertinent aspects of the underlying chemistry were explored. In darkness, pterin, lumazine, and isoxanthopterin were completely stable, whilst the other pteridines showed increasing instability in the order shown above. Excepting oxylumazine, all the pteridines showed chemical reactivity in seawater attributed to its pH and not its salt content. On the other hand, oxylumazine showed marked lability in seawater attributable to its salt content and not its pH. This pteridine required minimal concentrations of salt and divalent trace-metal ions (such as Cu²⁺) to show the chemical reactivity observed in sea-water. When the salt present was NaC1 only, oxylumazine showed 1:1 oxidative conversion to dioxylumazine, but with the total salts of seawater the conversion was 2:1 with half of the oxylumazine being degraded, apparently non-oxidatively, to unidentified non-pteridine products; this latter degradation is attributed to the combination of anions present in seawater. Unlike oxylumazine, xanthopterin showed 1:1 oxidative degradation via leucopterin in seawater. In the light, all the pteridines showed greater instability than in darkness but with the same order of influence of substituents on their reactivity. Excepting leucopterin and dioxylumazine, the photolytic reactivity in seawater was attributable to its pH and not its salt content; this was also the case with oxylumazine which had shown anomalous behaviour in darkness. Leucopterin and dioxylumazine (both 6,7-dihydroxylated pteridines) gave evidence of reaction in seawater by formation of chelated complexes between their C₆-, C₇-hydroxyl-groups and the alkaline-earth divalent cations (Ca²⁺ , Mg²⁺ ) of seawater. Such complexation enhanced their photolytic degradation rates to levels achieved by these pteridines at pH 10 in the absence of seawater salts. The photolysis of the 6-hydroxylated pteridines (xanthopterin, oxylumazine) in seawater showed evidence of intermediate formation of the corresponding 6,7-dihydroxylated derivatives. It was concluded that the pteridines and uric acid may undergo considerable chemical turnover, without biological intervention, in the marine environment, whilst the more refractory purines would require biological agencies for significant breakdown and reutilization. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

A cruise of the R/V Yaquina off Oregon during June and July of 1968 provided data for a study of the relationships of hydrographic and chemical parameters to estimates of biological activity. The emphasis was on carbon and nitrogen reservoirs. Phytoplankton pigments, nitrogen and C/N ratio were used along with AOU and the nitrate content of the water to estimate the distribution of phytoplankton production. Sigma-t, AOU, and nitrate were used to define the hydrographic and chemical conditions. Upwelling was the major source of nitrate for the surface waters, and, consequently, phytoplankton production was most intense where upwelling was active. The Columbia River plume appeared to support a sizeable amount of phytoplankton production just south of the river mouth. Particulate nitrogen increased and particulate C/N ratio decreased as the water became more biologically productive. Chlorophyll, particulate nitrogen, and C/N ratio showed the effects of upwelling and the Columbia River plume on biological production. A subsurface negative AOU core was clearly defined in areal extent and intensity. Its occurrence was explained by inshore phytoplankton production, oxygen exchange with the atmosphere, and possible in situ phytoplankton production. / Graduation date: 1970

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 38-41). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Miami, 1975. / Vita. Includes bibliographical references (leaves 149-158).

Thesis (M.S.)--Naval Postgraduate School, 1977. / Includes bibliographical references (leaves 88-90).

Master of Science

No description available.