Thesis (Ph. D.)--University of Rhode Island, 2006. / Typescript. Includes bibliographical references (leaves 175-188).

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Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on Mar. 4, 2009). Includes bibliographical references (p. 21-28).

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.

Coastal nutrient loading is a growing concern in urbanized communities and has led to alterations in above- and belowground processes throughout estuarine systems. Mangrove forests are highly productive coastal habitats that exhibit large carbon stocks contained mostly to the deep soils. Since nutrient enrichment has been found to increase mangrove aboveground growth, it’s presumed that nutrient enrichment will also increase belowground respiration rates. Disturbances in soil nutrient content may alter the mangrove carbon cycle by increasing the amount of CO2 lost to the atmosphere from enhanced microbial and root respiration. In this study, soil respiration responded greatest to nitrogen enrichment, but pneumatophore root respiration responded greatest to phosphorus enrichment. Nutrient limitation can shift between different ecological processes and responses to nutrient enrichment tend to be system specific in tidally influenced ecosystems. Understanding the implications of coastal nutrient loading will improve ecosystem models of carbon exchange and belowground processes. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 124-142).

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 69-72). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 156-175).

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 51-57). Also available on the World Wide Web.

Thesis (doctoral)--Chalmers Tekniska högskola, 1972. / "Akademisk avhandling för filosofie doktorsexamen i kemi ... fredagen den 2 juni 1972 ... Chalmers tekniska högskola."