# Grooves in forereefs act as transport channels to deliver coral rubble during tropical cyclones

## TL;DR

This study shows that grooves in coral reefs help transport rubble during storms, supporting the stability of coral islands.

## Contribution

First evidence that spurs and grooves act as transport channels for coral rubble during tropical cyclones.

## Key findings

- SAGs can transport rubble onshore during high-energy events.
- This process helps maintain reef islands and rubble-based ecosystems.
- Grooves facilitate both offshore and onshore sediment movement.

## Abstract

The long-term stability of coral reef islands and associated reef top sedimentary landforms requires the delivery of sediment from the forereef, but the rates and pathways of sediment delivery to these systems remain unclear. Spurs and grooves (SAGs) are ubiquitous geomorphic features fringing coral reefs, characterised by shore-normal coral ridges (spurs) separated by channels (grooves) with either bare substrate or a relatively low sediment infill. SAGs dissipate wave energy, facilitate offshore sediment transport and enhance nutrient exchange. Here we present the first evidence that SAG can also act as channels for onshore transport of rubble during high-energy events, contributing to maintaining reef islands and rubble-based ecosystems.