Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1986. / Vita. Includes bibliographical references (leaves 208-215).

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (p. 109-121).

Originally issued as the author's Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2006. / "February 2006." "Doctoral dissertation." "Department of origin: Marine Chemistry and Geochemistry." "Joint Program in Oceanography/Applied Ocean Science and Engineering"--Cover. Includes bibliographical references.

Marine sediments play an important role in the global carbon cycle, where they are ultimately important for recycling of carbon. At the sediment-water interface carbon is in constant movement both into and out of the sediment. However some environments are more important for the natural storage of carbon. Over long time scales this process has a role in climate regulation. Measuring the total O2 uptake represents a good proxy for the turnover of organic material at the sediment surface in oxygenated sediments, and equally the release of O2 represents benthic primary production. Many important biological processes are regulated by the availability of O2 at the seabed including: fauna composition and activity, phosphate exchange, nitrogen cycling and burial of organic material. Understanding of the rate and efficiency at which carbon turnover is occurring in marine sediments provides a valuable insight to the regulatory role they play in climate control. Investigation of marine sediments is best done in situ where possible, and the development of benthic “landers” has allowed measurements to be conducted at the sediment-water interface. Most recently, a novel approach known as “Eddy Correlation” (EC) has been developed. It allows quantification of the O2 exchange across any surface from simultaneous measurements of vertical velocity flow and oxygen concentration within the benthic boundary layer. The large sediment area accounted for; the high measuring frequency and the non-invasive nature are theoretical advantages over traditional methods such as benthic chamber incubations and O2 microprofiles. This study has shown that it is difficult to achieve consistent and improved measurements using EC compared to traditional methods due to the complex nature of the equipment and data analysis. Data does suggest that EC can be a strong complimentary tool for benthic carbon exchange studies. This project presents the first use of this technology across a range of benthic environments, from temperate coastal sediments and maerl beds to high-Arctic sediments and sea-ice. The method has allowed accurate quantification of the benthic remineralisation rates and carbon turnover efficiency in the coastal and maerl environments, but less so for the more complex under sea ice and cold Arctic environments. Rates presented agree well with other published studies documenting the use of this state-of-the-art technology.

Thesis (Ph. D.)--College of William and Mary. / Vita. Includes bibliographical references. Also available online.

Thesis (M.S.)--Florida State University, 2006. / Advisor: Joel Kostka, Florida State University, College of Arts and Sciences, Dept. of Oceanography. Title and description from dissertation home page (viewed Oct. 24, 2006). Document formatted into pages; contains viii, 101 pages. Includes bibliographical references.

Continental margin sediments play an important role in marine biogeochemical cycles, partly due to high primary production rates and efficient export of organic matter to sediments in margin environments. This thesis presents studies of solute exchange in fine-grained sediments representative of slope and rise environments, and carbon and nitrogen cycling in sandy sediments dominant in continental shelves worldwide. Results of these studies advance understanding of the role of benthic processes on marine ecosystems. In fine-grained sediments, solute exchange by diffusion, biological mixing and bioirrigation can be quantified using in situ flux chambers with inert tracer additions. Mechanistic models of chamber tracer transport across the seabed indicate that in organic-rich sediments, bioirrigation and mixing dominate over a wide range of bottom water oxygen levels, reflecting the patchiness and versatility of benthic macrofaunal communities. Positive correlations between benthic oxygen and tracer fluxes appear site-specific. Reliable chamber volume estimates derived from mechanistic models reveal that empirical fits to chamber tracer datasets may overestimate chamber volume and benthic solute fluxes. The biogeochemistry of sandy, highly permeable sediments that dominate continental shelves is largely unknown because of the difficulty in sampling and studying them under natural conditions. Novel sediment reactors were developed and used to mimic in situ porewater advection and natural sedimentary conditions. Compositional changes of natural seawater, with and without the addition of