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Magnesium sulfate ion association in seawaterGates, Richard Fredrick 04 March 1969 (has links)
Graduation date: 1969
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An investigation of high resolution dissolved oxygen profiles off the Oregon coastJeter, Hewitt Webb 09 August 1972 (has links)
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
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Phosphate equilibria in seawater and interstitial watersAtlas, Elliot Leonard 05 June 1975 (has links)
Graduation date: 1976
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Processes affecting the oceanic distribution of carbon dioxideCulberson, Charles Henry 03 May 1972 (has links)
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
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The chemical (non-biological) and photolytic transformations of pteridines and purines effected by the salts of seawater, and their ecological significanceLandymore, Arthur Frederick January 1971 (has links)
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
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Factors influencing the salinity difference between the North Atlantic and North Pacific oceansSkov, Niels Aage 11 March 1965 (has links)
Graduation date: 1965
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Determination of the apparent dissociation constants of phosphoric acid in seawaterKester, Dana R. 02 May 1966 (has links)
Graduation date: 1966
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Techniques of solvent extraction of organic material from natural watersCronin, John Thomas, 1935- 12 May 1967 (has links)
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
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The partial equivalent volumes of salts in seawaterDuedall, Iver W. 12 May 1966 (has links)
Graduation date: 1966
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Calcium analysis in seawater by an ion sensitive electrodeBradford, Wesley L. 09 May 1968 (has links)
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
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