Meta-Study of Carbonate Sediment Delivery Rates to Indo-Pacific Coral Reef Islands

Coral reef islands are amongst the most vulnerable environments to sea-level rise (SLR). Recent physical and numerical modeling studies have demonstrated that overwash processes may enable reef islands to keep up with SLR through island accretion. Sediment supply to these islands from the surrounding reef system is critical in understanding their morphodynamic adjustments, but is poorly constrained due to insufficient knowledge about sediment delivery rates. This paper provides the first estimation of sediment delivery rates to coral reef islands. Analysis of topographic and geochronological data from 28 coral reef islands indicates an average rate of sediment delivery of c. 0.1 m³ m⁻¹ yr⁻¹, but with substantial inter-island variability. Comparison with carbonate sediment production rates from census-based studies suggests that this represents one quarter of the amount of sediment produced on the reef platform. Results of this study are useful in future modeling studies for predicting morphodynamic adjustments of coral reef islands to SLR.