Biogeochemical applications of compound-specific radiocarbon analysis
MetadataShow full item record
LocationSanta Monica Basin
Santa Barbara Basin
KeywordCarbon; Isotopes; Biochemical markers; Biogeochemistry; Roger Revelle (Ship) Cruise Pulse-32
Compound-specific carbon isotopic (δ13C and Δ14C) data are reported for lipid biomarkers isolated from Santa Monica Basin (SMB) and Santa Barbara Basin (SBB) surface sediments. These organic compounds represent phytoplanktonic, zooplanktonic, bacterial, archaeal, terrestrial, and fossil carbon sources. The lipids include long-chain n-alkanes, fatty acids (as FAMEs), n-alcohols, C30 mid-chain ketols and diols, sterols, hopanols, and ether-linked C4o-biphytanes of Archaea. The data show that the carbon source for most of the biomarkers is marine euphotic zone primary production or subsequent heterotrophic consumption of this biomass. Two lipid classes represent exceptions to this finding. Δ14C values for the n-alkanes are consistent with mixed fossil and contemporary terrestrial plant sources. The archaeal isoprenoid data reflect chemoautotrophic growth below the euphotic zone. The biomarker class most clearly representing marine phytoplanktonic production is the sterols. It is suggested, therefore, that the sterols could serve as paleoceanographic tracers for surface-water DIC. The isotopic data are used to construct two algebraic models. The first calculates the contributions of fossil and modem vascular plant carbon to 5MB n-alkanes. This model indicates that the Δ14C of the modern component is +235% (post-bomb) or 0% (pre-bomb). The second model uses these values to determine the origin of sedimentary TOC. The results are comparable to estimates based on other approaches and suggest that ~60% of SMB TOC is of marine origin, modern terrestrial and fossil sources contribute ~10% each, and the remaining ~20% is of unknown origin.
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 October 1999
Showing items related by title, author, creator and subject.
Experimental and seismological constraints on the rheology, evolution, and alteration of the lithosphere at oceanic spreading centers deMartin, Brian J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-02)Oceanic spreading centers are sites of magmatic, tectonic, and hydrothermal processes. In this thesis I present experimental and seismological constraints on the evolution of these complex regions of focused crustal ...
Ecology of chemical defenses of algae against the herbivorous snail, Littorina littorea, in the New England rocky intertidal community Geiselman, Joy Ann (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1980-02)In the New England rocky intertidal community, space is dominated by two perennial plant types, brown fucoid algae (Ascophyllum nodosum and several species of Fucus) in the mid zones and the red alga Chondrus crispus ...
Lipoproteins and heat shock proteins as measures of reproductive physiology in the soft shell clam, Mya arenaria Clayton, Maureen E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-06)Reproduction is an important physiological process in marine bivalve molluscs. Experiments were designed to examine the role of lipoproteins and heat shock proteins in normal physiological processes of the soft shell ...