Growth of Western Australian corals in the Anthropocene

Brief description

Twenty-seven long cores were collected between October 2008 and September 2010 from massive Porites sp. colonies at six locations covering approximately 1000 km of the coast of Western Australia. The sampling locations included two reefs in the Rowley Shoals: Clerke Reef and Imperieuse Reef; three locations within the Ningaloo Reef Tract: Bundegi, Tantabiddi and Coral Bay; and the Houtman Abrolhos Islands. \n \nAll sampled colonies were <=2 m in height and selected from the leeward side of the reef or island at depths <6 m below the lowest astronomical tide. Spatial and temporal variations in three annual coral growth parameters; annual extension (linear distance between adjacent density minima (cm/y)), skeletal density (g/cm³) and calcification rate (the product of skeletal density and annual extension, g/cm²/y) were examined, as measured by gamma densitometry using standard procedures. \n \nWhile some cores extended back to the 18th century, focus was on the period 1900-2010, which was common to the majority (70%) of cores, and provided sufficient replication at each location and overlap with instrumental SST observations. Average monthly SST were obtained from the HadISST 1.1 database, available from the British Atmospheric Data Centre. \n \nCalcification anomalies were calculated for each core as the percent difference between the annual calcification rate and the long-term average for the period 1900-2010. Calcification anomalies were then averaged for each six locations and for all 27 cores. Linear regression (Generalized Linear Model (GLM) and non-linear regression (Generalized Additive models were used to examine the influence of time, SST and location on the calcification average and anomaly data. All models were analysed using the statistical package R.\n This research was undertaken to: \n1. determine if there have been significant changes in calcification rates in coral reefs in Western Australia over time \n2. determine if there is any relationship between any changes calcification rates and observed changes in sea surface temperature (SST).\n

Lineage

Maintenance and Update Frequency: notPlanned

Statement: Statement: The standard procedures used are described in: \nChalker BE and Barnes DJ (1990) Gamma densitometry for the measurement of skeletal density. Coral Reefs 9: 11-23. \n \nThe models used are described in: \nPinheiro JC and Bates DM (2000) Mixed-effects models in S and S-plus. Springer Verlag, New York. \n \nThe statistical package R was developed by: \nR Development Core Team (2011) R Foundation for Statistical Computing, Vienna, Austria. \n

Notes

Credit
Cooper, Timothy F, Dr (Principal Investigator)

Credit
Lough, Janice M, Dr (Custodian)