Uncovering the role of biomineralisation in otolith trace element uptake by microstructural and microchemical analysis
type: CreativeWork
description: Otolith biomineralisation was examined in order to uncover its role in trace element uptake within otolith structures by microstructural and chemical analysis. The mechanism of otolith elemental incorporation, the orientation of aragonite and the organic matrix in otoliths of four marine species were investigated in conjunction with the otolith growth patterns and the distribution of trace and minor elemental composition. Results for otoliths of Platycephalus bassensis, Chrysophrys auratus, Trachurus novaezelandiae and Lates calcarifer suggest a common biomineralisation mechanism for marine species, with consistent results across all species. The aragonite orientation, as mapped by electron backscatter diffraction (EBSD), revealed the aragonite c-axis was preferentially aligned parallel with the otolith growth axis and perpendicular to the insoluble organic matrices orientation, as determined by Raman microspectroscopy, in the otoliths of Platycephalus bassensis, Chrysophrys auratus, Trachurus novaezelandiae and Lates calcarifer. The orientation results indicate that otolith mineral growth is directed and controlled by the organic matrix, which acts as a template for the mineral growth, constraining the aragonite orientation and alignment. The organic rich zones (D-zone bands) within the otolith were composed of both insoluble and soluble organic matrices in all four species, with the insoluble matrices bridging the gap between mineral rich zones (L- zone bands) so as to retain crystal orientation across the otolith. Optimisation of electron probe microanalysis (EPMA) quantitative mapping achieved both high spatial resolution (<3 μm) and two dimensional visualisation of the fine scale Sr and S distributions in the otoliths with minimal otolith damage. The otolith growth patterns showed a clear association with the distribution of Sr and S, with D-zone bands exhibiting elevated concentrations of both elements as compared to the L-zone bands. Further examination by la…
abstract: Otolith biomineralisation was examined in order to uncover its role in trace element uptake within otolith structures by microstructural and chemical analysis. The mechanism of otolith elemental incorporation, the orientation of aragonite and the organic matrix in otoliths of four marine species were investigated in conjunction with the otolith growth patterns and the distribution of trace and minor elemental composition. Results for otoliths of Platycephalus bassensis, Chrysophrys auratus, Trachurus novaezelandiae and Lates calcarifer suggest a common biomineralisation mechanism for marine species, with consistent results across all species. The aragonite orientation, as mapped by electron backscatter diffraction (EBSD), revealed the aragonite c-axis was preferentially aligned parallel with the otolith growth axis and perpendicular to the insoluble organic matrices orientation, as determined by Raman microspectroscopy, in the otoliths of Platycephalus bassensis, Chrysophrys auratus, Trachurus novaezelandiae and Lates calcarifer. The orientation results indicate that otolith mineral growth is directed and controlled by the organic matrix, which acts as a template for the mineral growth, constraining the aragonite orientation and alignment. The organic rich zones (D-zone bands) within the otolith were composed of both insoluble and soluble organic matrices in all four species, with the insoluble matrices bridging the gap between mineral rich zones (L- zone bands) so as to retain crystal orientation across the otolith. Optimisation of electron probe microanalysis (EPMA) quantitative mapping achieved both high spatial resolution (<3 μm) and two dimensional visualisation of the fine scale Sr and S distributions in the otoliths with minimal otolith damage. The otolith growth patterns showed a clear association with the distribution of Sr and S, with D-zone bands exhibiting elevated concentrations of both elements as compared to the L-zone bands. Further examination by la…
author: McFadden, Aoife
language: en
keywords: Otoliths, biomineralisation, biochemistry, trace element analysis
date published: 2016
date modified: 2026-07-24T00:50:59Z
provider: University of Adelaide
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Adelaide

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property ID: Handle
value: http://hdl.handle.net/2440/118860