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Titre du document / Document title

Linkages between coral assemblages and coral proxies of terrestrial exposure along a cross-shelf gradient on the southern Great Barrier Reef

Auteur(s) / Author(s)

JUPITER S. (1 2) ; ROFF G. (3) ; MARION G. (3) ; HENDERSON M. (3) ; SCHRAMEYER V. (3) ; MCCULLOCH M. (1) ; HOEGH-GULDBERG O. (3) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) ARC Centre of Excellence for Coral Reef Studies, The Australian National University, Canberra, ACT 0200, AUSTRALIE
(2) Australian Institute of Marine Science, PMB #3, Townsville MC, QLD 4810, AUSTRALIE
(3) ARC Centre of Excellence for Coral Reef Studies, Centre for Marine Studies, The University of Queensland, Brisbane, QLD 4072, AUSTRALIE

Résumé / Abstract

Coral core records, combined with measurements of coral community structure, were used to assess the long-term impact of multiple environmental stressors on reef assemblages along an environmental gradient. Multiple proxies (luminescent lines, Ba/Ca, δ15N) that reflect different environmental conditions (freshwater discharge, sediment delivery to the nearshore, nutrient availability and transformations) were measured in Porites coral cores collected from nearshore reefs at increasing distance from the intensively agricultural region of Mackay (Queensland, Australia). The corals provide a record (1968-2002) of the frequency and intensity of exposure to terrestrial runoff and fertilizer-derived nitrogen and were used to assess how the present-day coral community composition may have been influenced by flood-related disturbance. Reefs closest to the mainland (5-32 km offshore) were characterized by low hard coral cover (<10%), with no significant differences among locations. Distinct annual luminescent lines and elevated Ba/Ca values (4.98 ± 0.63 μmol mol-1; mean ± SD) in the most inshore corals (Round Top Island; 5 km offshore) indicated chronic, sub-annual exposure to freshwater and resuspended terrestrial sediment that may have historically prevented reef formation. By contrast, corals from Keswick Island (32 km offshore) indicated episodic, high-magnitude exposure to Pioneer River discharge during extreme flood events (e.g., 1974, 1991), with strongly luminescent lines and substantially enriched coral skeletal δ15N (12-14‰). The reef assemblages at Keswick and St. Bees islands were categorically different from all other locations, with high fleshy macroalgal cover (80.1 ± 7.2% and 62.7 ± 7.1%, respective mean ± SE) overgrowing dead reef matrix. Coral records from Scawfell Island (51 km offshore) indicated little exposure to Pioneer catchment influence: all locations from Scawfell and further offshore had total hard and soft coral cover comparable to largely undisturbed nearshore to middle shelf reefs of the southern Great Barrier Reef.

Revue / Journal Title

Coral reefs    ISSN  0722-4028   CODEN CORFDL 

Source / Source

2008, vol. 27, no4, pp. 887-903 [17 page(s) (article)] (1 p.3/4)

Langue / Language

Anglais

Editeur / Publisher

Springer, Berlin, ALLEMAGNE  (1982) (Revue)

Mots-clés anglais / English Keywords

Invertebrata

;

Coelenterata

;

Oceania

;

Australia

;

Great Barrier Reef

;

Cnidaria

;

Coral reef

;

Perturbation

;

Isotopes

;

Nitrogen

;

Barium

;

Luminescence

;

Great Barrier Reef

;

Terrestrial environment

;

Community

;

Coral

;

Mots-clés français / French Keywords

Invertebrata

;

Coelenterata

;

Océanie

;

Australie

;

Grande Barrière Corail

;

Porites

;

Cnidaria

;

Récif corallien

;

Perturbation

;

Isotope

;

Azote

;

Baryum

;

Luminescence

;

Récif Grande Barrière

;

Milieu terrestre

;

Communauté

;

Corail

;

Mots-clés espagnols / Spanish Keywords

Invertebrata

;

Coelenterata

;

Oceania

;

Australia

;

Cnidaria

;

Arrecife coralino

;

Perturbación

;

Isótopo

;

Nitrógeno

;

Bario

;

Luminiscencia

;

Gran Barrera de Arrecifes

;

Medio terrestre

;

Comunidad

;

Coral

;

Mots-clés d'auteur / Author Keywords

Porites

;

Luminescence

;

Barium

;

Nitrogen isotope

;

Coral assemblage

;

Disturbance frequency

;

Localisation / Location

INIST-CNRS, Cote INIST : 19219, 35400018434556.0160

Nº notice refdoc (ud4) : 20856688



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