Organic phosphorus in marine sediments : chemical structure, diagenetic alteration, and mechanisms of preservation
Laarkamp, Kirsten L.
MetadataShow full item record
LocationSanta Barbara Basin
Phosphorus, an essential nutrient, is removed from the oceans only through burial with marine sediments. Organic phosphorus (Porg) constitutes an important fraction (ca. 25%) of total-P in marine sediments. However, given the inherent lability of primary Porg biochemicals, it is a puzzle that any Porg is preserved in marine sediments. The goal of this thesis was to address this apparent paradox by linking bulk and molecular-level Porg information. A newly-developed sequential extraction method, which isolates sedimentary Porg reservoirs based on solubility, was used in concert with 31P nuclear magnetic resonance spectroscopy (31P-NMR) to quantify Porg functional group concentrations. The coupled extraction/31P-NMR method was applied to three sediment cores from the Santa Barbara Basin, and the first-ever high-resolution depth profiles of molecular-level Porg distribution during diagenesis were generated. These depth profiles were used to consider regulation of Porg distribution by biomass abundance, chemical structure, and physical protection mechanisms. Biomass cannot account for more than a few percent of sedimentary Porg. No evidence for direct structural control on remineralization of Porg was found. Instead, sorptive protection appears to be an important mechanism for Porg preservation, and structure may act as a secondary control due to preferential sorption of specific Porg compound classes.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2000
Showing items related by title, author, creator and subject.
Flow and sediment properties influencing erosion of fine-grained marine sediments : sea floor and laboratory experiments Young, Robert Alexander (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-09)Erosion processes involving fine-grained marine sediments were studied by using an in situ flume to erode undisturbed bottom sediments on the sea floor in Buzzards Bay, a shallow marine embayment off the Massachusetts coast. ...
Henrichs, Susan M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1980-08)Dissolved free amino acids (DFAA) were measured in interstitial water samples squeezed from sediments collected in a variety of depositional environments. These sediments were further characterized by measurements of ...
White, Helen K. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2006-02)To provide a new perspective on the fate of both natural organic matter and hydrophobic organic contaminants (HOCs) in marine sediments, we have investigated the relationship between radiocarbon (14C) age and the different ...