American scientists have reported the first successful sexual reproduction of Atlantic coral in a laboratory setting.

Researchers at the Florida Aquarium in Tampa recently announced their results. They described them as a "scientific breakthrough."

Scientists believe the reproduction method could help save Atlantic corals in danger of disappearing completely.

Corals are groups of small organisms called polyps. These polyps live within a hard skeleton made of limestone. Millions of corals grow together to form coral reefs. The reefs support many kinds of sea life. Coral reefs also support fishing activities and protect inland waterways.

Pillar corals in a water tank at the labs of The Florida Aquarium Conservation Center in Apollo Beach where recently the spawning occurred on August 22, 2019, in Apollo Beach, Florida.

Corals can reproduce either asexually or sexually. Asexually, new small polyps break off from parent polyps to expand or begin new colonies. This process is also known as fragmentation.

In sexual reproduction, some corals produce sperm and eggs and release them into the water. The eggs and sperm join to form free-floating larvae. The larvae are either fertilized within the body of a polyp or in the water in a process called spawning.

The laboratory experiment at the Florida Aquarium involved inducing corals to release their eggs and sperm in laboratory tanks.

Scientists in other countries have reported similar success, but the Florida Aquarium's experiment was a first for the United States. The Florida team cooperated with researchers from the Britain-based Horniman Museum and Gardens, which has successfully induced spawning of different kinds of Pacific coral.

In order for the experiment to be a success, scientists had to control the tank to create conditions as similar as possible to a natural ocean environment. The Florida Aquarium team spent months doing this.

The effort included changing the temperatures in summer and winter and using technology to recreate sun and moon activity. Such conditions serve as biological signs for the organisms that it is time to spawn.

Keri O'Neil is a senior coral scientist at the Florida Aquarium. She said the "massive and fully synchronized spawning" was a success because it happened at exactly the predicted time for wild spawning. She added that by creating the right conditions, "you can change the game for coral restoration."

"We'll be able to do this for dozens of species, and it opens up a world of new possibilities," O'Neil told Reuters news agency.

Chief coral scientist Keri O'Neil cleans an aquarium full of pillar coral just a few days before the animals would successfully spawn in an aquarium for the first time at a Florida Aquarium facility in Apollo Beach, Florida on August 14, 2019. (Reuters/Lu

The scientists plan to use the method to spawn new coral colonies to help repopulate Florida's struggling coral reefs. The reef system is one of the largest in the world. But it has suffered years of damage from climate change, pollution and disease.

Amelia Moura is the science program manager for the Florida-based Coral Restoration Foundation. The organization carries out its own major fragmentation programs. This involves "farming" large numbers of corals that are later "outplanted" to the reef.

Moura told VOA there are many causes for the widespread destruction of Atlantic coral. All, however, are linked to climate change.

"Our corals, like many around the world, are at risk of warming waters and ocean acidification - all which come under the large umbrella of climate change."

In addition, she said Florida coral is also currently suffering from "a massive disease outbreak" likely related to poor quality water flowing into the ocean.

Moura said it was "really exciting" to learn about the successful spawning of Atlantic coral. She said the results were especially important because they happened with pillar coral. This kind of coral has a more complex reproductive process than other species.

She added that there are very few adult colonies of this coral species still living. So, the new laboratory spawning can make a huge difference in coral restoration efforts in Florida and elsewhere.

"This new influx of genetic material is really critical for the success of the species long-term."

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