Nom du corpus

Corpus Systématique Végétale

Titre du document

Rhodoliths and coralliths of Muri Lagoon, Rarotonga, Cook Islands

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Éditeur
Springer (journals)
Langue(s) du document
Anglais
Type de document
Research-article
Nom du fichier dans la ressource
Syst_veg6_v2_002170
Auteur(s)
  • Terence P. Scoffin 1
  • David R. Stoddart 2
  • Alexander W. Tudhope 3
  • Colin Woodroffe 4
Affiliation(s)
  • 1) Geology Department, University of Edinburgh, EH9 3IW, Edinburgh, UK
  • 2) Department of Geography, University of Cambridge, CB2 3EN, Cambridge, UK
  • 3) Geology Department, Aberdeen University, AB9 1AS, Aberdeen, UK
  • 4) N.A.R.U., Australian National University, P.O. Box 41321, 5792, Casuarina, NT, Australia
Résumé

Free-living massive and branching spheroidal growths (about 5 cm diameter) of calcareous red algae (rhodoliths) and corals (coralliths) occur in abundance on the sea bed of shallow Muri Lagoon on Rarotonga's reef flat. The rhodoliths are composed of one or more species of Neogoniolithon, Lithophyllum, Tenarea, and Porolithon; the coralliths are Pavona varians (Verrill) and Porites lutea (Milne-Edwards and Haime). Muri Lagoon is the only area on Rarotonga's reef flat that is sheltered by reef islands from ocean waves. The tidal currents, which are predominantly unidirectional in Muri Lagoon, are concentrated by the reef islands into channels through which sand and gravel sediment is regularly transported. However, these prevailing currents do not normally roll the rhodoliths and coralliths. The results of field experiments on the pick-up velocity of the various types of spheroidal structure, combined with observations on growth histories of massive coralliths as revealed by the non-concentric nature of skeletal density banding, indicate that the rhodoliths and coralliths may remain static for periods up to several months yet maintain a complete envelope of living tissue. This downward survival may depend on the strong currents. Not only is the water flushing through the upper millimetre or so of the sediment substrate, but it is also capable of moving the sand and gravel grains which laterally support the rhodoliths and coralliths so that no one point of a spheroidal structure is in direct contact with the substrate for a fatal length of time. Massive rhodoliths have a high preservation potential as discrete spheroidal structures; in contrast, branching rhodoliths and coralliths are prone to fragmentation, and massive coralliths grow into stable microatolls. We conclude that a similar assemblage of rhodoliths, coralliths and microatolls in the fossil record may be indicative of the former existence of contemporary reef flat islands.

Catégories Science-Metrix
  • 1 - natural sciences
  • 2 - biology
  • 3 - marine biology & hydrobiology
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
Catégories Scopus
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Aquatic Science
Catégories WoS
  • 1 - science ; 2 - marine & freshwater biology
Identifiant ISTEX
0F905D0C8A38D34762FA47E282A8BC60323B7C96
Revue

Coral Reefs

Année de publication
1985
Présence de XML structuré
Non
Score qualité du texte
9.72
Version PDF
1.3
Type de publication
Journal
ark:/67375/1BB-0962PC3L-8
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