HR: 13:55h
AN: B13E-02    [Abstracts]
TI: Foraminiferal Inter-species and Intra-individual Crystal Structure Variability Characterized by Micro-Raman Spectroscopy
AU: * Hintz, C J
EM: chris.hintz@msci.sc.edu
AF: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 United States
AU: Shaw, T J
EM: shaw@mail.chem.sc.edu
AF: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 United States
AU: Angel, S M
EM: angel@mail.chem.sc.edu
AF: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 United States
AU: Powell, A C
EM: powell@mail.chem.sc.edu
AF: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 United States
AB: Raman spectroscopy was used to investigate inter-species and intra-individual differences in crystal lattice structure in cultured benthic foraminiferal tests. This {\it non-destructive} technique can be used to map differences in crystal structure associated with different mechanisms of biomineralization. Inter-species differences in {\it Bulimina aculeata} and {\it Rosalina vilardeboana} produced significantly different Raman spectra (bands: {\it B. aculeata} 281, 482, 711, 1002, 1086 cm$^{-1}$; {\it R. vilardeboana} 224, 620, 798, 1001, 1032, 1156 cm$^{-1}$). Intra-individual variability of Raman peak shifts and peak widths, which indicate variation in crystalline structure, was observed in localized regions of {\it B. aculeata} tests. The intra-individual variability was consistent with significant differences in minor element signatures measured by ICP-MS, and correlate with variation in biomineralization processes during the foraminifer's lifespan. These variations were observed in oxidatively-cleaned and photobleached foraminifers. Subsequent reductive cleaning of the tests and reanalysis produced significantly less spectral variability, potentially due to partial dissolution of the less-ordered calcite. Further work is planned to elucidate the source of Raman spectral variation by identifying structurally varying regions, isolating them by high-resolution laser microsectioning, and then analyzing them directly for minor element composition by ICP-MS.
DE: 4840 Microbiology
DE: 4894 Instruments and techniques
DE: 4267 Paleoceanography
DE: 3030 Micropaleontology
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting