Localized zinc distribution in shark vertebrae suggests differential deposition during ontogeny and across vertebral structures

PLoS One. 2018 Jan 11;13(1):e0190927. doi: 10.1371/journal.pone.0190927. eCollection 2018.

Abstract

The development of shark vertebrae and the possible drivers of inter- and intra-specific differences in vertebral structure are poorly understood. Shark vertebrae are used to examine life-history traits related to trophic ecology, movement patterns, and the management of fisheries; a better understanding of their development would be beneficial to many fields of research that rely on these calcified structures. This study used Scanning X-ray Fluorescence Microscopy to observe zinc distribution within vertebrae of ten shark species from five different orders. Zinc was mostly localised within the intermedialis and was generally detected at levels an order of magnitude lower in the corpus calcareum. In most species, zinc concentrations were higher pre-birth mark, indicating a high rate of pre-natal zinc deposition. These results suggest there are inter-specific differences in elemental deposition within vertebrae. Since the deposition of zinc is physiologically-driven, these differences suggest that the processes of growth and deposition are potentially different in the intermedialis and corpus calcareum, and that caution should be taken when extrapolating information such as annual growth bands from one structure to the other. Together these results suggest that the high inter-specific variation in vertebral zinc deposition and associated physiologies may explain the varying effectiveness of ageing methodologies applied to elasmobranch vertebrae.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / metabolism*
  • Aging / pathology
  • Animals
  • Calcium / metabolism
  • Linear Models
  • Microscopy, Fluorescence
  • Sharks / anatomy & histology
  • Sharks / growth & development*
  • Sharks / metabolism*
  • Species Specificity
  • Spine / diagnostic imaging
  • Spine / growth & development*
  • Spine / metabolism*
  • Zinc / metabolism*

Substances

  • Zinc
  • Calcium

Grants and funding

We thank the NSW Department of Primary Industries and the Department of Biological Sciences at Macquarie University for providing funding and some of the samples for this research. An AINSE research award ALNGRA13029 allowed a dialogue between ANSTO and Macquarie University that led to this project. Access to the Australian Synchrotron was supported under the NSW Industry Synchrotron Access Scheme, funded by the NSW Office of Science and Research. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.