Raman analysis of octocoral carbonate ion lattice disorder along a natural depth gradient, Kona coast, Hawai‘i

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dc.contributor.advisor Kahng, Samuel E.
dc.contributor.advisor Sabine, Christopher L.
dc.contributor.author Conner, Kyle Anthony
dc.contributor.department Oceanography
dc.date.accessioned 2022-07-05T19:58:51Z
dc.date.available 2022-07-05T19:58:51Z
dc.date.issued 2022
dc.description.degree M.S.
dc.identifier.uri https://hdl.handle.net/10125/102268
dc.subject Chemical oceanography
dc.subject Mineralogy
dc.subject Geochemistry
dc.subject carbonate ion disorder
dc.subject Mg-calcite
dc.subject Octocorals
dc.subject Raman spectroscopy
dc.title Raman analysis of octocoral carbonate ion lattice disorder along a natural depth gradient, Kona coast, Hawai‘i
dc.type Thesis
dcterms.abstract Both environmental and vital effects cause carbonate lattice disorder in biogenic Mg-calcites. A major component of this disorder is driven by the incorporation of Mg through environmental forcing and growth rate kinetics although non-Mg factors (e.g., other cation/anion impurities, organic molecules) also contribute. Understanding the drivers of Mg content in biogenic calcite and its effects on disorder has implications for octocoral Mg paleo-proxies and the stability and diagenetic alteration of their calcitic skeletons. However, prior studies of biogenic Mg-calcites have often been complicated by sampling inconsistencies over space and time and potential intra-sample Mg variability. This study aims to analyze the relative contributing factors of octocoral Mg-calcite lattice disorder along gradients of both depth and growth rate. Calcitic octocorals (Corallidae and Isididae, N = 28) were collected from 221–823 m across a natural gradient in biogeochemical parameters (pH: 7.4–7.9, T: 5–16°C) off the Kona coast of Hawai‘i Island and analyzed using Raman spectroscopy. Samples were collected during the same month, controlling for potential seasonal variability. Raman spectral parameters from the ν1 peak quantified total carbonate lattice disorder (full width at half maximum height [FWHM] of ν1) and Mg content (ν1 position, Raman shift). The total lattice disorder was then partitioned into Mg-driven and non-Mg driven components (residual FWHM). The total lattice disorder and Mg content decreased significantly with increasing depth, correlating with temperature and carbonate system parameters. The Mg-temperature relationships from this study were also consistent with prior studies. Residual FWHM did not correlate to any environmental parameters. When measured across an intra-sample gradient of (ontogenetic) growth rate, total lattice disorder, Mg content, and residual FWHM increased with growth rate for all but one taxon, demonstrating the kinetic effect of growth rate as well as potential taxon specific vital effects. These results provide insight into how environmental and growth rate kinetic effects independently affect different components of carbonate lattice disorder (Mg content and non-Mg factors). These findings also suggest that Raman spectroscopy may be helpful in quantifying solubility within biogenic calcites.
dcterms.extent 87 pages
dcterms.language en
dcterms.publisher University of Hawai'i at Manoa
dcterms.rights All UHM dissertations and 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 from the copyright owner.
dcterms.type Text
local.identifier.alturi http://dissertations.umi.com/hawii:11264
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