How Corals Protect Themselves Against Climate Change

Alice Amelia Thomas, Zenger News - 
Coral reefs are under threat from coral bleaching, which eventually leads to starvation. Global warming can disrupt the algae on the coral, which give it its vivid colors, leaving it white, fragile, and more likely to starve.

Now scientists have revealed how a special internal cooling system is saving stony corals–or Scleractinia–from environmental stress.

A study, led by the Alfred Wegener Institute (AWI) and the Max Planck Institute for Marine Microbiology in Bremerhaven, Germany, had its findings published in the journal Current Biology on August 23.

Zenger News obtained a statement from AWI that explains that stony corals make use of cilia—tiny, hair-like projections on the surfaces of their cells that influence "flow conditions" and protect the creatures from dangerous concentrations of oxygen.

While oxygen is vital for most animals and plants, too much of it can be harmful to corals, especially in warm water. Most coral reefs are made up of hundreds to thousands of tiny organisms known as polyps that have a symbiotic relationship with a group of algae that is provided with shelter in exchange for energy-rich sugars.


A general view of a school of fish and a sea fan in a healthy coral reef off the coast of Isla Mujeres, Mexico on September 26, 2018. Scientists from the Alfred Wegener Institute in Germany found that stony corals make use of tiny, hair-like projections on the surfaces of their cells that protect the creatures from dangerous concentrations of oxygen. Getty Images/Donald Miralle© Getty Images/Donald Miralle

These sugars are produced from water and carbon dioxide through the use of sunlight in a process known as photosynthesis. This process becomes problematic when temperatures are too high, which causes the algae to release dangerous substances, instead of supplying the polyps with energy.

The polyps then "get rid of their roommates" by throwing them out, which causes the reefs to lose their color and, in most cases, die.


A soft coral lies amid a carpet of various coral species at 45 metres depth on July 14, 2022, in Eilat, Israel. Most coral reefs are made up of hundreds to thousands of tiny organisms known as polyps that have a symbiotic relationship with a group of algae that is provided with shelter in exchange for energy-rich sugars. Getty Images/Lukasz Larsson Warzecha© Getty Images/Lukasz Larsson Warzecha

However, Dr. Cesar O. Pacherres, of the University of Copenhagen and one of the study's authors, explained that this does not always occur. He stated: "Not all corals on a reef fall victim to this."

To figure out why the team studied the coexistence of the hard coral creatures with a group of algae under a magnifying glass. By following the trail of oxygen, the scientists discovered it is actively distributed to areas where it is needed by the cilia.

Co-author Dr. Soeren Ahmerkamp added: "The trick is that the cilia on the surface of the coral create small vortices through coordinated beating."

Produced in association with SWNS.

Corals have developed a sophisticated internal fan system to protect themselves from climate change, a study has revealed.
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