Settlement receptors of coral larvae

Coral reproduction is vital for reef recovery.

In sexual reproduction, corals release eggs and sperm into the water column where tiny larvae develop.

To grow into an adult coral colony, a larva needs to find a suitable location on the reef where it can attach to the reef. This attachment is called ‘settlement’.

Larvae are guided to appropriate settlement spots by environmental signs such as the molecules of a crustose coralline algae.

This algae molecule acts like a key in a lock where a precise match activates the larvae to settle and transform into a very small coral.

While some keys that induce settlement in coral larvae have been identified, the cellular receptors of larvae that sense the environment and receive the key like a lock are still unknown. 

Ramona Brunner counting coral larvae

In the National Sea Simulator in the spawning season 2020, scientists of AIMS and JCU are collaborating to investigate the receptors that play a role in the settlement of Acropora millepora larvae.

They will extract and study the existing receptor proteins in coral larvae and test the settlement response of coral larvae to different drugs.

These drugs are specific for certain receptor types and act as a block to the opening of the ‘lock’.

If the algae ‘key’ still causes a settlement response in the presence of the blocking drug, the researchers can conclude that the specific receptor is most likely not involved in the molecular process of settlement.

If the algae key doesn’t induce a settlement response in the presence of the blocking drug, the targeted receptor might play a role in the molecular pathway of settlement in Acropora millepora larvae.

Knowing the settlement receptor and its activating key, could help reef restoration by increasing the rate of larvae that settle and transform into small corals.