Standard Presentation Australian Marine Sciences Association Annual Meeting 2023

Let’s stick together: Rubble binding in the Indian and Pacific Oceans (#229)

Tania Kenyon 1 , Peter J Mumby 1 , Karen Eigeland 1
  1. University of Queensland, St. Lucia, QUEENSLAND, Australia

Rubble generation on coral reefs is increasing due to more frequent and severe disturbances including mass coral bleaching, cyclones and ship groundings. Recovery of rubble beds is constrained by physical and biological processes, including rubble mobilisation and binding. Rubble that has been stabilised by binding organisms (e.g., sponges, coralline algae) can provide a suitable, stable substrate for coral recruitment. Yet, the mobilisation of loose, unstable rubble can inhibit or break binding, and restrain coral recruitment, limiting the recovery of rubble beds. In the Maldives, and on the Great Barrier Reef (GBR), we investigated rates and strengths of rubble binding across a gradient of water quality, depth and exposure. In both locations, binding rates were generally faster in shallow, exposed sites and, on the GBR, in offshore locations. Rubble binding strength depended more on the binding organism type than on the quantity of binds, with the strongest binders being vermetid snails, serpulid worms, bivalves, tunicates and coralline algae. The results from our research will help to aid managers in predicting the natural stabilisation and recovery potential of degraded, rubble-dominated reefs. Rubble beds with poor recovery outlooks can be prioritised for management strategies that include assisted rubble stabilisation, where appropriate.