Investigation of light as a limiting factor in the distribution of benthic symbiont bearing foraminifera on the Great Barrier Reef (MTSRF Project 3.7.1)

Temporal Range: From 08-Aug-2005 To 07-Dec-2005

Resource Summary

During August 2005, sediment was collected from four reefs in the Whitsunday Islands and two adjacent midshelf reefs, situated along a previously studied water quality gradient. The reefs at Repulse and Lindeman Islands are influenced by discharge generated by the Proserpine and O'Connell Rivers. In the outer Whitsunday Islands, Hook and Edward Islands reefs, are subject to terrestrial influence, which is largely derived from the islands themselves. The midshelf reefs, Barb Reef and Reef 19-138 are essentially unaffected by terrestrial discharge.

Two sites were randomly chosen on the less exposed leeward side of each reef. At each site samples were collected from three depth zones along the reef slope: 2 to 5 m, 6 to 8 m and 9 to 13 m. For each depth zone at each site, three core samples were collected using cut-off 60 ml syringes. Each syringe was pressed vertically into the sand for at least half its length and all but the top 1cm of each core was discarded. Samples were combined to form a single sample per depth station and preserved in ethanol. Samples were later rinsed, dried and subsamples of symbiont bearing foraminifera identified.

Amphistegina spp., Calcarina spp. and Heterostegina depressa, collected from the sediment sampling sites at Edward Island were cultured in tubes within a series of tanks in an outdoor aquarium system set up in mid September 2005 at AIMS. Specimens were subjected to three light regimes: open to sunlight, 30% sunlight and 10% sunlight.

Over a two week period in November/December 2005, light measurements, temperature and salinity were recorded in each tank. Images of each individual foraminifera were taken before and at intervals during the experiment and the surface area of each individual determined.

Pulse-amplitude-modulated (PAM) fluorometry was applied to assess the health of the symbiotic diatoms and their adaptation to various light levels. Additional specimens of the three taxa were collected from the Whitsunday Islands and the same process was applied within 2 hours of collection.

Field and experimental studies were undertaken to investigate the importance of light as an environmental factor influencing physiology and distribution of tropical benthic foraminifera.

Resource Usage:

Use of the AIMS data is for not-for-profit applications only. All other users shall seek permission for use by contacting AIMS. Acknowledgements as prescribed must be clearly set out in the user's formal communications or publications.

Cite this Record
Australian Institute of Marine Science (AIMS). (2009), Investigation of light as a limiting factor in the distribution of benthic symbiont bearing foraminifera on the Great Barrier Reef (MTSRF Project 3.7.1),, accessed 14-Aug-2020.