The lack of availability of a single, complete paper on the analysis of a digital data acquisition system for in situ oceanographic measurements brought about the present work. In order to compile an accurate technical paper on such a complex system, it was necessary to design, construct, and calibrate a system for the in situ measurement of various physical and chemical properties of sea water. A unique digital encoding circuit was developed which utilizes the basic principles of null balance, resistance ratio bridge and potentiometer measurements. The circuit is a uniquely loaded binary ladder resistance network. Variation of the loading allows resistance ratio and potentiometric measurements to be made over different ranges with a constant high degree of resolution. The developed system has the capability of measuring any parameter which can be converted into a varying voltage, current, or resistance. The range over which the measurement can be made is adjustable; and the resolution equals ± 0.006% of the full range value. The resolution is constant over the full range, as a result of the analog-to- digital converter linearity characteristics. / Graduation date: 1968

Originally issued as the author's Thesis (O.E. and M.S.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution.

Earlier studies on the relationship between mercury concentration in fish – or alternatively bioavailability of mercury in aquatic systems – and different abiotic oceanographic factors such as water temperature, pH and salinity, have shown that such associations often exist. The results are not always consistent between studies, however. The aim of this study is to investi­gate if this type of relationships can be established in Baltic herring, Clupea harengus, with the use of temporal monitoring data from the northern Bothnian Bay (northern Sweden), compiled within Swedish monitoring programmes. The abiotic factors being assessed in this study are water temperature, salinity, dissolved oxygen, pH and measurements of nutrient content in the water; phosphate, total phosphorus and total nitrogen. Relationships between these parameters and mercury concentration in herring were investi­gated using multiple linear regression. Generally however, relationships were absent, and only one significant association was found, a positive relationship between total phosphorus in water and herring mercury load. Difficulty to reveal relationships in the presence of confoun­ding factors, which cannot be controlled for when using monitoring data from the field, is suggested as one reason for the absence of such relationships. Furthermore, the somewhat incomplete monitoring data of abiotic factors likely made it hard to detect any relationships.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (p. 90-93).

Thesis (M.S.)--Naval Postgraduate School, 1993. / "September 1993." Includes bibliographical references (p. 70-72).

Thesis (Ph. D.)--University of British Columbia, 1998. / Includes bibliographical references (leaves 186-199).

Thesis (Ph.D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences; and the Woods Hole Oceanographic Institution), February 2000. / Includes bibliographical references. / Compound-specific carbon isotopic (613C and A14C) data are reported for lipid biomarkers isolated from Santa Monica Basin (SMB) and Santa Barbara Basin (SBB) surface sediments. These organic compounds represent phytoplanktonic, zooplanktonic, bacterial, archaeal, terrestrial, and fossil carbon sources. The lipids include long-chain n-alkanes, fatty acids (as FAMEs), n-alcohols, C30 mid-chain ketols and diols, sterols, hopanols, and ether-linked C40-biphytanes of Archaea. The data show that the carbon source for most of the biomarkers is marine euphotic zone primary production or subsequent heterotrophic consumption of this biomass. Two lipid classes represent exceptions to this finding. A14C values for the n-alkanes are consistent with mixed fossil and contemporary terrestrial plant sources. The archaeal isoprenoid data reflect chemoautotrophic growth below the euphotic zone. The biomarker class most clearly representing marine phytoplanktonic production is the sterols. It is suggested, therefore, that the sterols could serve as paleoceanographic tracers for surface-water DIC. The isotopic data are used to construct two algebraic models. The first calculates the contributions of fossil and modern vascular plant carbon to SMB n-alkanes. This model indicates that the A14C of the modern component is +235%o (post-bomb) or 0%o (pre-bomb). The second model uses these values to determine the origin of sedimentary TOC. The results are comparable to estimates based on other approaches and suggest that -60% of SMB TOC is of marine origin, modern terrestrial and fossil sources contribute -10% each, and the remaining -20% is of unknown origin. / by Ann Pearson. / Ph.D.

Thesis (Sc. D.)--Joint Program in Oceanographic Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), 1987. / Bibliography: p. 164-171. / Vita. / by James Henry Miller. / Sc.D.

This thesis investigates inversion techniques used to determine the geoacoustic properties of a shallow-water waveguide. The data used were obtained in the Shallow Water '06 Modal Mapping Experiment in which four buoys drifted over a system of subbottom channels. The method used was perturbative inversion using modal eigenvalues as input parameters, which were found using an autoregressive spectral estimator. This work investigates the differences between a "channel" region and a "no channel" region based on an inferred stratigraphic model. Inversions were performed on data from a single buoy both at individual frequencies and multiple frequencies simultaneously. Since the use of multiple frequencies and a certain set of constraints proved to be an effective method of inversion, the method was applied to data from the other three buoys as well. It is shown that the "channel" and "no channel" regions have significantly different sound speed profiles. / by Rebecca Weeks. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Thesis (S.M.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering and the Woods Hole Oceanographic Institution), September 2001. / Includes bibliographical references (leaves 65-67). / As part of Phase III of the U.S. GLOBEC Georges Bank program, drogued drifters and dye tracer were released into the pycnocline on the southern flank of Georges Bank to measure advective and diffusive transport relative to the tidal mixing front in May 1999. Potential density measurements placed the tidal mixing front around the 50-55 m isobath on the southern flank. Drogued drifter movement relative to the front was on the order of the drifter's slip velocity and therefore did not support the existence of a mean, advective flow. No movement relative to the front of the dye patch center of mass also indicated a lack of advective flow. Diffusive transport did occur as the dye patch spread laterally both toward and away from the front much as would be predicted by the diffusion relationship of Okubo (1971), who summarized diffusion experiments in the surface ocean. The dye did not spread symmetrically, but was rather elongated along the isobaths. This can be attributed to vertical shear in the along-isobath current that was measured by the shipboard ADCP. / by Jody M. Katerin. / S.M.