Soft corals show greater resilience to bleaching during ocean heat waves

Marine biologists have found that the soft coral on Lord Howe Island, about 700 kilometers northeast of Sydney, is more resilient to coral bleaching than the hard coral on the island.

A team led by the University of New South Wales (NSW) surveyed coral reefs on the southernmost island of the world during, shortly after, and seven months after the 2019 ocean heat wave.

In a Thursday release, Ph.D. student and lead author of the dissertation, Rosemary Steinberg, said that during the bleaching phenomenon, Sir Howe’s soft corals looked better overall than hard corals.

“This suggests that as Lord Howe Island continues to bleach, successful soft coral seeds can become more common on these reefs than on hard cousins,” she says. I did. Challenges that soft coral-dominated coral reefs can pose. “

Steinberg differs in that most photographs of coral reefs show hard coral, which is usually hard and immobile, whereas soft ones do not form a hard skeleton under the tissue and are flexible.

“The fact that some species not only survived bleaching, but also showed no physical response to ocean heat waves, is great news,” she said.

“We know that while future bleaching can result in the loss of some species, different coral communities can restore coral reefs.”

Teams say that some soft corals are still showing signs of bleaching, but resistant species are common soft corals, and Steinberg is a habitat for these important coral reefs while more sensitive species recover. And found that they wanted to be able to maintain functionality.

According to Steinberg, the various soft corals responded differently to elevated temperatures, one with whitening, one with no response, and the other with a better response than normal.

Epoch Times Photo
Coral bleaching on Lord Howe Island. (Fatima / Adobe Stock)

Coral bleaching occurs when symbiotic organisms (microorganisms that inhabit coral cells and provide energy and color) are expelled from the coral. This is commonly seen in ocean heat waves.

But the researchers are Xeniasp. It responded to heat waves by acquiring more of these symbiotic organisms. So, at least in theory, coral seeds should produce more energy as a result of heat waves.

“I was really surprised. Xenia is a very charismatic and beautiful species and I’m not entirely sure what happened,” Steinberg said.

“Maybe it was a unique stress response, or it prospered during the heat waves, or at least the water was warmer than the temperature on Lord Howe Island.

“Knowing which groups and types of coral can survive in a warming world is important for protecting coral reefs,” she said, and this knowledge tells researchers what future coral reefs will be. He added that it helps to predict what it looks like and what kind of marine life it supports. What services can they provide to the communities they depend on?

Hard corals build rock structures on coral reefs, and without them the reefs begin to collapse. It’s important to discover that soft corals are more likely to survive in the warmer waters of eastern Australia, and to understand what role soft corals play in maintaining them. Hard leaf structure together.

The research team is now trying to better understand how soft corals and their symbiotic algae deal with ocean heat waves.

“We are investigating the types of algae and bacteria that have survived the heat waves that have been expelled from the corals and filled the empty space,” Steinberg said.

“This is to understand if there are interventions such as adding more heat resistant symbiotic organisms to the reefs that could help the Coral of Lord Howe survive and recover from future ocean heat waves. Helps. “

A complete dissertation on the team’s research can be found in the journal The frontier of physiology.

Steve Milne


Steve is a Sydney-based Australian reporter with sports, arts and politics. He is an experienced English teacher, a qualified nutritionist, a sports enthusiast, and an amateur musician. Contact him at [email protected].