Sedimentary environments of the Central Region of the Great Barrier Reef of Australia

Coral Reefs ◽  
1985 ◽  
Vol 4 (2) ◽  
pp. 81-93 ◽  
Author(s):  
Terence P. Scoffin ◽  
Alexander W. Tudhope
Keyword(s):  
Great Barrier Reef ◽  
Central Region ◽  
Barrier Reef ◽  
Sedimentary Environments

Water circulation around Britomart Reef, Great Barrier Reef, during July 1979

1980 ◽  
Vol 31 (4) ◽  
pp. 415 ◽  
Author(s):  
E Wolanski ◽  
M Jones
Keyword(s):  
Great Barrier Reef ◽  
Sea Level ◽  
Central Region ◽  
Reef Flat ◽  
Water Circulation ◽  
Barrier Reef ◽  
Trade Winds ◽  
Sea Breezes ◽  
Coral Sea ◽  
Sea Level Oscillations

Weather and currents at eight sites were measured and drogue trajectories obtained in July 1979 at Britomart Reef, a middle reef located at 18�16'S.,146� 38'E. in the central region of the Great Barrier Reef province. The longest current records (3 weeks) were obtained at two sites in passes between the Coral Sea and the Great Barrier Reef Lagoon where westerly currents modulated by tides were observed. Analysis of residuals also showed the importance of wind-driven secondary circulation. Non-tidal sea-level oscillations were very small. Shorter current records (1-10 days) at six sites in the lagoon and on the reef flat showed a predominant northerly flow, also modulated by tides and wind. A residual anticlockwise water circulation existed in the lagoon where flushing was controlled more by winds than by tides. The rise in sea level over the reef flat as a result of waves breaking was negligible. Temperature differences between air and water accounted for the cooling of the water column during the expedition. Constant south-east trade winds were experienced at the reef, while on land the wind was weaker. more variable, and often dominated by land-sea breezes.

Patterns of zonation of assemblages of the Lutjanidae, Lethrinidae and Serranidae (Epinephelinae) within and among mid-shelf and outer-shelf reefs in the central Great Barrier Reef

1997 ◽  
Vol 48 (2) ◽  
pp. 119 ◽  
Author(s):  
Stephen J. Newman ◽  
David McB. Williams ◽  
Garry R. Russ
Keyword(s):  
Great Barrier Reef ◽  
Central Region ◽  
Spatial Scales ◽  
Outer Shelf ◽  
Barrier Reef ◽  
Fishing Pressure ◽  
Back Reef ◽  
Outer Continental Shelf ◽  
Spatial Differences ◽  
Reef Zones

Visual censuses were used to quantify the distribution and abundance of the Lutjanidae, Lethrinidae and Serranidae in three reef zones (windward reef slope, lagoon, back reef) of three reefs on the mid shelf and three reefs on the outer continental shelf in the central region of the Great Barrier Reef. Significant spatial variability was identified in the abundances of many species between locations (outer-shelf and mid-shelf communities), between reefs (high-abundance v. low-abundance reefs), and within reefs (characteristic communities within zones on individual reefs). Species of the Lutjanidae, Lethrinidae and Serranidae were found to occur in assemblages that were characteristic of major zones (windward reef slopes, lagoons and leeward back reefs), this pattern being consistent within and among shelf locations. Care will need to be taken in determining the appropriate spatial scales of sampling in any future experiments (e.g. manipulations of fishing pressure) to ensure that the effects of smaller-scale spatial differences are not confounded when larger-scale comparisons are made.

Taphonomic bias and time-averaging in tropical molluscan death assemblages: differential shell half-lives in Great Barrier Reef sediment

Paleobiology ◽  
2009 ◽  
Vol 35 (4) ◽  
pp. 565-586 ◽  
Author(s):  
Matthew A. Kosnik ◽  
Quan Hua ◽  
Darrell S. Kaufman ◽  
Raphael A. Wüst
Keyword(s):  
Great Barrier Reef ◽  
Time Averaging ◽  
Burial Depth ◽  
Barrier Reef ◽  
Amino Acid Racemization ◽  
Sedimentary Environments ◽  
Depositional Setting ◽  
Lagoonal Sediment ◽  
Water Carbonate ◽  
Age Estimates

Radiocarbon-calibrated amino acid racemization ages of 428 individually dated shells representing four molluscan taxa are used to quantify time-averaging and shell half-lives with increasing burial depth in the shallow-water carbonate lagoon of Rib Reef, central Great Barrier Reef, Australia. The top 20 cm of sediment contains a distinct, essentially modern assemblage. Shells recovered at depths from 25 to 125 cm are age-homogeneous and significantly older than the surface layer. Taxon age distributions within sedimentary layers indicate that the top 125 cm of lagoonal sediment is thoroughly mixed on a sub-century scale. The age distributions and shell half-lives of four taxa (Ethalia, Natica, Tellina, and Turbo) are found to be largely distinct. Shell half-lives do not coincide with any single morphological characteristic thought to infer greater durability, but they are strongly related to a combined durability score based on shell density, thickness, and shape. These results illustrate the importance of bioturbation in tropical sedimentary environments, indicate that age estimates in this depositional setting are sensitive to taxon choice, and quantify a taxon-dependent bias in shell longevity and death assemblage formation.

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