Presence of skeletal banding in a reef-building tropical crustose coralline alga

Lewis, B., Lough, J. M., Nash, M. C. and Diaz-Pulido, G. (2017) Presence of skeletal banding in a reef-building tropical crustose coralline alga. PLoS ONE, 12(10), e0185124. (doi: 10.1371/journal.pone.0185124) (PMID:28976988) (PMCID:PMC5627911)

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Abstract

The presence of banding in the skeleton of coralline algae has been reported in many species, primarily from temperate and polar regions. Similar to tree rings, skeletal banding can provide information on growth rate, age, and longevity; as well as records of past environmental conditions and the coralline alga’s growth responses to such changes. The aim of this study was to explore the presence and characterise the nature of banding in the tropical coralline alga Porolithon onkodes, an abundant and key reef-building species on the Great Barrier Reef (GBR) Australia, and the Indo-Pacific in general. To achieve this we employed various methods including X-ray diffraction (XRD) to determine seasonal mol% magnesium (Mg), mineralogy mapping to investigate changes in dominant mineral phases, scanning electron microscopy–electron dispersive spectroscopy (SEM-EDS), and micro-computed tomography (micro-CT) scanning to examine changes in cell size and density banding, and UV light to examine reproductive (conceptacle) banding. Seasonal variation in the Mg content of the skeleton did occur and followed previously recorded variations with the highest mol% MgCO3 in summer and lowest in winter, confirming the positive relationship between seawater temperature and mol% MgCO3. Rows of conceptacles viewed under UV light provided easily distinguishable bands that could be used to measure vertical growth rate (1.4 mm year-1) and age of the organism. Micro-CT scanning showed obvious banding patterns in relation to skeletal density, and mineralogical mapping revealed patterns of banding created by changes in Mg content. Thus, we present new evidence for seasonal banding patterns in the tropical coralline alga P. onkodes. This banding in the P. onkodes skeleton can provide valuable information into the present and past life history of this important reef-building species, and is essential to assess and predict the response of these organisms to future climate and environmental changes.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Lewis, Dr Bonnie
Authors: Lewis, B., Lough, J. M., Nash, M. C., and Diaz-Pulido, G.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
ISSN (Online):1932-6203
Copyright Holders:Copyright © 2017 Lewis et al.
First Published:First published in PLoS ONE 12(10):e0185124
Publisher Policy:Reproduced under a Creative Commons License

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