CNN  — 

As oceans warm due to climate change, some coral reefs have been devastated in recent years by bleaching events that cause them to die and damage the biodiversity that depends on them.

Multiple studies are underway to understand more about these bleaching events and if corals can bounce back.

While bleaching is associated with the stark white skeletal remains of corals after they have lost their live tissue, an opposite effect can also take place when such an event occurs.

It’s known as colorful bleaching, where corals seem to amp up their pigments and provide brilliant displays of neon color.

Colorful bleaching has been observed since 2010 in coral reefs around the globe, but the mechanism and reasoning behind it hasn’t been understood. Now, researchers believe the glowing corals are sending a message that they’re trying to survive.

The study published Thursday in the journal Current Biology.

Acropora corals experienced colorful bleaching in the New Caledonian barrier reef, located in New Caledonia in the South Pacific, in 2016.

Corals may seem like beautiful plants on the ocean floor, but they’re actually animals. Many of them rely on symbiosis — a mutually beneficial coexistence where tiny algae live within the corals’ cells. Coral branches are actually comprised of compact colonies that include thousands of tiny animals called polyps.

The corals get energy from photosynthesis provided by the algae, and the algae take shelter, nutrients and carbon dioxide from the corals. Those photosynthetic pigments provided by the algae cause many corals to appear brown.

But this arrangement is a fragile one that can be disrupted by rising ocean temperatures.

Oceans tend to reach a specific maximum temperature during hot seasons. But if the temperature rises just 1 degree Celsius above that threshold, it can spell disaster for corals.

The heat causes the coral and algae relationship to break down. After the algae disappears, the white limestone skeletons of the corals are exposed, making them appear bleached. If the corals can’t retrieve their algae, the vulnerable corals starve and can be struck by disease. When the corals die, reefs collapse and decline, and so does the ocean biodiversity that depend on them.

Acropora corals experienced colorful bleaching in 2010 off the coast of the Philippines.

Significant bleaching events occurred during record ocean temperatures between 2015 and 2017, causing the most widespread and devastating mass coral bleaching ever recorded, according to the study. Heat stress affected many coral reefs during the El Niño event between 2014 and 2017.

The Great Barrier Reef, Florida Keys and Fiji were just some of the reefs impacted worldwide.

However, at least 15 colorful bleaching events from across the world between 2010 and 2019, including one at the Great Barrier Reef in Australia, are included in the new study.