|
Vol. 51 No. 8, 2012
Reef-Scale
Assessment of Intertidal Large Benthic Foraminifera Populations on One
Tree Island, Great Barrier Reef and Their Future Carbonate Production
Potential in a Warming Ocean
Steve S. Doo1,*, Sarah Hamylton2, and Maria Byrne1,3
1School of Medical Sciences, University of Sydney, NSW 2006, Australia
2School of Earth and Environmental Sciences, University of Wollongong, NSW 2522, Australia
3Schools of Medical and Biological Sciences, University of Sydney, NSW 2006, Australia
Steve S. Doo, Sarah Hamylton, and Maria Byrne (2012) Populations
of large benthic foraminiferans (LBFs) that inhabit coral reef
platforms are major producers of calcium carbonate (CaCO3)
in reef ecosystems. This study documented the population density
of living intertidal LBF populations at One Tree Reef (OTR), southern
Great Barrier Reef, in a community dominated by Marginopora vertebralis and Baculogypsina sphaerulata. Densities of 7.7 × 103 M. vertebralis individuals (ind.)/m2 and 4.5 × 105 B. sphaerulata ind./m2
were estimated for these populations in May 2011. We applied
remote-sensing technology to determine reef-scale estimates of suitable
Foraminifera habitats and used these to estimate overall stocks of LBF
populations on the intertidal algal flat at OTR of ca. 2800 metric
tons. The growth rate of M. vertebralis was determined in a laboratory study, and the data were used to calculate the annual CaCO3 production of the reef flat by the LBF population. The response of M. vertebralis
to ocean warming was investigated using 3-week incubations at
temperatures ranging from ambient sea surface temperature to
+6°C. There were significant decreases in growth and concomitant
CaCO3 production in 6°C warmer water, which resulted in shell dissolution of M. vertebralis.
These results indicate that climate-driven ocean warming projected for
the region will result in significant decreases in CaCO3 production in overall foraminiferan populations, although species-specific effects should be further investigated.
Key words: Carbonate production, Foraminifera, Remote sensing, Great Barrier Reef, Algal flat.
*Correspondence: Tel: 61-2-93515167. E-mail:stevedoo@gmail.com
|
