Isotopic constraints on the sources and associations of organic compounds in marine sediments

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 modes of association in aquatic sediments and soils. Radiocarbon is a sensitive tracer of OM provenance, with variations in its natural abundance reflecting the age and origin of material. The main objective has been to determine the significance of these associations, and to assess how they affect the transport, bioavailability, preservation and residence times of organic compounds in the environment. Our results indicate that the majority of HOCs that persist in marine sediments are solvent-extractable and incorporation into insoluble sediment residues is not quantitatively significant. For pristine sediments, systematic variations in 14C content are observed between different chemically defined sedimentary organic fractions. These variations are dependent on organic matter inputs and/or the affects of diagenesis. Our observations also provide evidence for the protection of labile marine carbon by chemical binding.

Department dc:contributor.department

Joint Program in Oceanography

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• White, Helen K

Advisor dc:contributor.advisor

• Christopher M. Reddy.

• Joint Program in Oceanography.
• Earth, Atmospheric, and Planetary Sciences.
• Woods Hole Oceanographic Institution.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/34566
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/34566

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/34566