Fig 2. Stages in the stabilisation and binding of rubble.

Stages of the natural stabilisation of rubble fields and eventual conversion to reef framework. A) shelter from strong hydrodynamic activities, a depression in bathymetry or particle organisation into stable bedforms allows the rubble pieces to settle, interlock and stabilise; b) pioneer binding organisms such as fleshy and calcareous algae settle on the rubble; c) intermediate binders such as cryptic and erect sponges create greater stability; and d) late stage binders and coral settlement.