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Oxygen Consumption Rates in Permeable Gulf of Mexico Sediments

Title: Oxygen Consumption Rates in Permeable Gulf of Mexico Sediments.
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Name(s): Laschet, Matthias, author
Huettel, Markus, professor directing thesis
Dittmar, Thorsten, outside committee member
Iverson, Richard, committee member
Department of Earth, Ocean and Atmospheric Sciences, degree granting department
Florida State University, degree granting institution
Type of Resource: text
Genre: Text
Issuance: monographic
Date Issued: 2008
Publisher: Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: The objective of this study was to investigate oxygen consumption rates in permeable Gulf coast sediments and their link to changes in the water and sediment chlorophyll concentrations. The investigation was initiated to improve our understanding of the biogeochemical functioning of these sediments and their role in the coastal cycling of organic matter. Although sand is the most abundant sediment type on the continental shelf, the decomposition process in sediments affected by advective pore water exchange is not understood. Boundary-layer flows transport organic matter, nutrients and electron acceptors into nearshore permeable sediments thereby affecting benthic photosynthesis, microbial activity and oxygen dynamics. A series of advection chamber measurements was used to determine temporal and spatial variations in O2 consumption at two study sites located in the Northeastern Gulf of Mexico, with one site located at the exposed south side of St. George Island and the other more sheltered site in Apalachicola Bay. A time series analyzing sediment cores and overlying water samples provided data on the temporal and spatial dynamics of sedimentary and water column chlorophyll and oxygen concentrations. Sediment grain size and porosity were similar at the two sites, although Gulf sediments in general were more permeable (Gulf: 1.84 x10-11 to 5.29 x10-11, Bay 7.3x10-12 to 2.11x10-11) and had higher chlorophyll content at the Bay side (Gulf: 1.1 to 10.6 μg cm-3, Bay: 8.8 to 47.2 μg cm-3). At the Gulf site, O2 consumption rates ranged from 2 mmoles m-2 d-1 in winter to 17 mmoles m-2 d-1 in summer, while at the Bay site a maximum of 62 mmoles m-2 d-1 was recorded in August 2006 and a minimum of 11 mmoles m-2 d-1 in the winter. These rates demonstrate high metabolic activity in Gulf of Mexico nearshore sands despite their relatively low content of labile organic matter as reflected by their chlorophyll concentrations. Bay sediment chlorophyll in the upper 3 cm reached highest values in spring (March 2007: 47 μg cm-3), and the Gulf site in summer (July 2006: 10 μg cm-3). Our results highlight the role of filtering sublittoral sands as sites for high benthic organic matter turnover.
Identifier: FSU_migr_etd-3271 (IID)
Submitted Note: A Thesis submitted to the Department of Oceanography in partial fulfillment of the requirements for the degree of Master of Science.
Degree Awarded: Fall Semester, 2008.
Date of Defense: October 22, 2008.
Keywords: Oxygen Consumption, Marine Sediments
Bibliography Note: Includes bibliographical references.
Advisory Committee: Markus Huettel, Professor Directing Thesis; Thorsten Dittmar, Outside Committee Member; Richard Iverson, Committee Member.
Subject(s): Oceanography
Oceanography
Atmospheric sciences
Meteorology
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_migr_etd-3271
Owner Institution: FSU

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Laschet, M. (2008). Oxygen Consumption Rates in Permeable Gulf of Mexico Sediments. Retrieved from http://purl.flvc.org/fsu/fd/FSU_migr_etd-3271