Graduation date: 1969

Dissolved oxygen profiles made with an in situ polarographic device reveal structure in the form of inversions and gradient changes in the 100-600 meter depth zone off Oregon. Inversions 10-70 meters thick are traced over distances of 40 miles in some cases and are bracketed by a distance of 8 miles in others. The horizontal extent of these features agrees with observations of similarly-sized temperature and salinity structure reported by Stommel and Federov (1967) and by Hamon (1967). Oxygen maxima are correlated with changes in the vertical temperature gradient. Corresponding salinity minima are sometimes found. This relationship between properties is consistent with the formation of oxygen structure by a horizontal mixing process off Oregon. The existence of significant horizontal gradients in properties over distances of tens of miles favors the interleaving of dissimilar waters along density surfaces. A quantitative example of the horizontal mixing process yields temperature gradient changes near oxygen maxima similar to those observed. The in situ production of oxygen structure by layers of oxygen-consuming materials is considered unlikely in the size range studied. A transient state vertical model indicates that the consumption layers required for this mechanism are more intense than is consistent with recent biomass measurements. Diffusion calculations are used to model the decay of oxygen maxima. Calculated lifetimes range from 2.6 days for features 15 meters thick to 48.1 days for features 60 meters thick. These are considered estimates of the time scales associated with the stratification process. / Graduation date: 1973

Graduation date: 1976

The stoichiometric model of organic decomposition in seawater (Redfield, Ketchum, and Richards, 1963) was used to describe the oceanic distribution of total carbon dioxide. It was assumed that the concentration of total carbon dioxide was the sum of three terms: (1) the initial concentration of carbon dioxide, (2) the increase in carbon dioxide due to the oxidation of organic matter, and (3) the increase in carbon dioxide due to the solution of calcium carbonate. The initial concentration of carbon dioxide was calculated by assuming that surface seawater is in equilibrium with atmospheric carbon dioxide. This assumption allowed the temperature dependence of the initial concentration to be estimated. The vertical and horizontal distribution of total carbon dioxide in the Pacific, Indian, and South Atlantic Oceans was shown to conform to this model. In particular, values of the oxidative ratio (ΔC/ΔO) calculated from field data agreed with the theoretical value of Redfield et al. (1963). The model for the distribution of total carbon dioxide was applied to the vertical distribution of carbon-13 at the North Pacific (1969) GEOSECS intercalibration station (Kroopnick, Deuser, and Craig, 1970). Values of δC¹³ calculated from the stoichiometric model agreed to within ± 0.3‰ with the measured values at this station. Near-bottom chemical measurements were made on three cruises: YALOC-69 to the Eastern Tropical Pacific, Y6908F off the Oregon Coast, and TT-46 to the Caribbean Sea and North Atlantic. The emphasis during these cruises was on chemical gradients in deep water, and 39 stations were occupied at depths greater than 2000 m. Salinity, oxygen, pH, alkalinity, silicate, phosphate, nitrate, and nitrite were measured at heights from 0.5 to 300 m above the bottom. No measurable salinity, oxygen, silicate, phosphate, nitrate, or nitrite gradients were observed. A statistically significant near-bottom increase in pH and alkalinity was found. However, the increase was small and could have resulted from undetected analytical and/or sampling errors. / Graduation date: 1972

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

Graduation date: 1965

Graduation date: 1966

Manual and automatic solvent extraction techniques were used to concentrate organic material from natural waters. Field and laboratory extractions were compared to determine the most probable method and best solvents for efficient concentration of organic material from estuarine and sea waters. The large scale extraction processes utilizing extractors made from 55 gallon drums were operated both by manually moving perforated metal discs through the water and solvent for mixing and by bubbling air through the aqueous-solvent mixture. Resulting samples proved large enough for the detection of short-chain fatty acids (carbon length 1 through 10). Identification of organic constituents was by gas chromatography-mass spectroscopy. Other portions of these samples were separated by column chromatography with subsequent analysis by infrared, visible, ultraviolet, and mass spectroscopy. The proximity of the Hanford Atomic Product Operations to the collecting area caused some of the organics to be labeled with trace amounts of radionuclides. A counter-current pulse column extractor was used at sea aboard the Research Vessel YAQUINA. The organic solvent, hexone, used in this extraction was distilled before and after the extraction with various fractions of solvent being kept for control. The extraction was carried out under varying chemical and physical conditions. The hexone was back-extracted into hydrochloric acid, sodium bicarbonate, or sodium hydroxide before analysis by flame-ionization gas chromatography and mass spectroscopy. Other portions of the product hexone were analyzed for total solid matter recovered and carbon, hydrogen, and nitrogen content. Small intermediate scale extractions were carried out in the laboratory using several solvents. Resulting organic material was analyzed by tandem gas chromatography-mass spectroscopy. Where possible, organic derivatives were prepared to aid in the identification of the recovered organic material. The advantages and disadvantages of large scale extractions and small laboratory procedures were discussed. / Graduation date: 1967

Graduation date: 1966

A newly developed calcium sensitive liquid-liquid membrane electrode is used to analyse seawater off the Oregon coast in waters fed by the Columbia River runoff. For the analysis, an application of the method of standard additions is used requiring the assumption that the seawater is of so high a salt concentration that a small change in the overall ionic strength is insufficient to disturb the electrode response to calcium. Two equations describing the behavior of the electrode are treated and one is found applicable for use in seawater. Analyses by electrode are compared with analyses of the same water by atomic absorption spectroscopy with a degree of scatter in the correlation which is largely accounted for by 10% of calcium accuracy in the electrode readout device. Overall laboratory precision of the electrode and readout was 3% of calcium per standard deviation. The electrode appears to be much better for analytical purposes than ± 10% of calcium concentration. / Graduation date: 1968