Sedimentological characteristics of key sea turtle rookeries: potential implications under projected climate change
M. M. P. B. Fuentes A C , J. L. Dawson A , S. G. Smithers A , M. Hamann A and C. J. Limpus BA School of Earth and Environmental Sciences, James Cook University, Douglas, Qld 4811, Australia.
B Queensland Environmental Protection Agency, Brisbane, Qld 4000, Australia.
C Corresponding author. Email: mariana.fuentes@jcu.edu.au
Marine and Freshwater Research 61(4) 464-473 https://doi.org/10.1071/MF09142
Submitted: 16 June 2009 Accepted: 16 September 2009 Published: 27 April 2010
Abstract
Sea turtles rely on reef islands for key parts of their reproductive cycle and require specific sediment characteristics to incubate their eggs and dig their nests. However, little is known about the sedimentological characteristics of sea turtle rookeries, how these sediment characteristics affect the vulnerability of rookeries to climate change, and the ecological implications of different sediment or altered sediment characteristics to sea turtles. Therefore, we described the sediment and identified the reef-building organisms of the seven most important rookeries used by the northern Great Barrier Reef (nGBR) green turtle population. We then reviewed the literature on the vulnerability of each identified reef-building organism to climate change and how various sediment characteristics ecologically affect sea turtles. Sediments from the studied rookeries are predominantly composed of well-sorted medium-grained to coarse-grained sands and are either dominated by Foraminifera, molluscs or both. Dissimilarities in the contemporary sedimentology of the rookeries suggest that each may respond differently to projected climate change. Potential ecological impacts from climate change include: (1) changes in nesting and hatchling emergence success and (2) reduction of optimal nesting habitat. Each of these factors will decrease the annual reproductive output of sea turtles and thus have significant conservation ramifications.
Additional keywords: Australia, carbonate sediments, coastal morphology, global warming, Great Barrier Reef, islands, marine turtles, nesting grounds, ocean acidification.
Acknowledgements
This work was supported and funded by the Queensland Parks and Wildlife Service (QPWS), the Australian Government's Marine and Tropical Sciences Research Facility and the Great Barrier Reef Marine Park Authority. We thank the traditional owners of the field sites for allowing access and granting permission to work on their land. We thank the staff and volunteers of the QPWS, Earthwatch and Erub community for sand sample collection. Special thanks go to Moses Wailu, Ian Bell and Kenny Bedford for facilitating work at Dowar Island, Milman Island and Bramble Cay, respectively. We are also thankful for the comments provided by Christopher T. Perry on an earlier version of this manuscript and three anonymous referees. Field work complies with the current laws of Australia and all permits necessary for the project were obtained (QPWS permit number WISPO4316207).
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