Green Corals are the Most Resistant to Bleaching

A study found that different colours of Acropora tenuis coral, specifically brown, purple, and yellow-green, found off the coast of Okinawa, Japan, demonstrated varying resilience to rising water temperatures and resultant bleaching.

During a notably warm summer in 2017, the purple and brown corals suffered bleaching, while the yellow-green corals showed resistance.

The research, published in G3, dismissed the initial theory that the differences were due to variations in symbiotic algae, zooxanthellae, housed by the coral.

Examination of the coral's genome identified genes coding for colouring proteins, leading to the observation that the corals produced differing amounts of these proteins depending on their colour.

However, the researchers concluded that the colour variation and resilience to thermal stress coincided with genetic mechanisms, not a causal relationship.