Colin WOODROFFE - Research Information

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Reef island evolution and climate change

Colin Woodroffe has a particular interest interest in the evolution of reef islands and their response to climate change. This includes:

 Evolution of reef islands in the Indian and Pacific Oceans
 Evolution of islands in Torres Strait

Evolution of reef islands in the Indian and Pacific Oceans

The vulnerability of coasts to extreme water levels has been tragically demonstrated by the Aceh tsunami and the New Orleans hurricane. Low-lying sandy islands perched on coral reefs appear especially vulnerable to the impacts of climate change, particularly as a result of sea-level rise associated with global warming. Our UOW-ANSTO collaborative studies using AMS dating of individual components within the sand have shown that reef islands in the eastern Indian Ocean and central Pacific Ocean have built progressively over the late Holocene (Woodroffe et al., 1999; Woodroffe and Morrison, 2001). Sandy reef islands are built from the skeletal remains of organisms (coral, algae, molluscs and foraminifera) that grow in the surrounding reef environments, and the islands have undergone continued oceanward growth through additional sediment input over the past 3000 years under conditions of slightly higher sea level.

References

Woodroffe, C.D., McLean, R.F., Smithers, S.G. and Lawson ,E. (1999) Atoll reef-island formation and response to sea-level change: West Island, Cocos (Keeling) Islands. Marine Geology 160, 85-104.

Woodroffe, C.D. and Morrison, R.J. (2001) Reef-island accretion and soil development on Makin, Kiribati, central Pacific. Catena 44: 245-261.

Woodroffe, C.D..., (2008) Reef-island topography and the vulnerability of atolls to sea-level rise.  Global and Planetary Change, 62, 77-96.

Evolution of islands in Torres Strait

Studies on Warraber island (Torres Strait) have extended initial stratigraphic research on the evolution of the reef platform (Woodroffe et al., 2007), through an ARC-funded research project aimed at integrateing studies of long-term (Holocene) reef-island formation and development, present-day sedimentary and hydrodynamic processes on reef flats and island beaches, and computer simulation modelling of island evolution and behaviour. This collaborative ARC-funded project between Colin Woodroffe (University of Wollongong), Peter Cowell (University of Sydney) and Roger McLean (Australian Defence Force Academy) involves four components: a) mapping, survey and sample collection; b) laboratory analysis (sediment analysis and radiometric dating); c) hydrodynamic and sediment process measurements in the surf zone (reef flat) and on the island beach face; and d) computer modelling. Much of the fieldwork and laboratory analysis has been undertaken as part of PhD studies by Deirdre Hart, now a lecturuer at University of Canterbury, Christchurch, New Zealand, and Bongkoch Samosorn.   Research is continuing in collaboration with Scott Smithers and Kevin Parnell at James Cook University, and involving PhD student Javier Leon.

Fieldwork has involved experiments to measure wave and current flows towards and around the island, sediment sampling was undertaken along 5 surveyed transects across the reef flat from the island beach to the reef edge, and along 16 beach profiles, and ecological surveys and sampling of reef flat flora, fauna and sediments conducted along the five reef flat transects. GIS has been used to investigate the morphology of the ref and of the ref island (Samosorn and Woodroffe, 2008). In 2004, fieldwork from the RV James Kirby included detailed swath mapping of the reef front of the Warraber Reef and the reef platforms to the north and south, and preliminary ecological examination of these reefs, and mapping of the reef islands.

References

Woodroffe, C.D., B. Samosorn, Q. Hua, and D.E. Hart (2007) Incremental accretion of a sandy reef island over the past 3000 years indicated by component-specific radiocarbon dating, Geophysical Research Letters, 34, L03602, doi:10.1029/2006GL028875.

Samosorn, B. and Woodroffe, C.D. (2008) Nearshore wave environments around a sandy cay on a platform reef, Torres Strait, Australia.  Continent Shelf Research, 28, 2257-2274.

Woodroffe, C.D., Kennedy, D.M., Hopley, D., Rasmussen, C. and Smithers, S.G. (2000) Holocene reef growth in Torres Strait. Marine Geology 170, 331-346.

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