News Excerpt

Researchers explore using healthy reef sounds to aid coral reef recovery.

More details about the news:

• Global warming has many consequences, including rising sea levels and changes in the frequency of extreme weather. Another is the destruction of coral reefs.
• However, not all coral bleaching events are due to warm water. Ocean acidification – which is when the pH of the water drops as more carbon dioxide dissolves in it – is another well-known cause. More acidic water reduces the availability of calcium minerals that the corals need to build and repair their exoskeleton.
•  Scientists studied the impact of playing healthy reef sounds on coral settlement rates in degraded reefs.
•  Field studies in the Virgin Islands showed increased settlement rates of corals near underwater speakers playing healthy reef sounds. Settlement rates decreased with distance from the speakers, indicating the influence of the sounds.
• The study suggests potential for using good sounds to aid coral reef recovery but requires further testing and refinement. Challenges such as optimal sound volume and large-scale implementation need to be addressed for practical application.

Coral bleaching

• Coral bleaching describes a natural process where corals lose their vibrant colours and turn white. This happens when corals are under stress due to an environmental disturbance.
• Coral bleaching is usually triggered by heat stress caused by increased water temperatures and UV radiation, but can occur due to other factors such as changes in water quality. 
• Corals get their colour from microscopic algae called zooxanthellae, which live inside their tissues. The relationship between corals and zooxanthellae is mutually beneficial – corals provide a protected environment for the algae, and algae provide food for the corals. 
•  During environmental stress however corals eject the algae, which means they lose their main food source. When the algae leaves, corals’ tissues become transparent, which exposes their white skeleton and makes them appear bleached.