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Researchers’ oceanside nursery provides home to thousands of at-risk corals


Staghorn coral (Acropora cervicornis). Credit: Wikipedia, CC BY 2.5

In a 600-gallon tank overlooking Port Everglades, tiny bits of brain coral and massive star coral grow serenely below the water’s surface. While some of these pieces are the size of a quarter, all of the 2,376 fragments at this nursery could make a difference.

“These are what we call corals of opportunity,” said Kyle Pisano, the manager of the coastal coral nursery. “Corals that have somehow become detached from the reef, by anchors or storms or something else.”

They bring these corals of opportunity, which would otherwise die, to the nursery to try and grow more coral, in an effort to bolster Florida’s struggling coral reef populations.

Researchers at Nova Southeastern University are propagating and studying coral at their Oceanographic Campus at Dr. Von D. Mizell-Eula Johnson State Park at Dania Beach. For the past 10 years they have grown coral at this nursery to preserve genetic diversity, create more coral for restocking in the ocean and save coral from disease.

In 2019, NSU researchers began the Noah’s Ark project in a coordinated effort to save corals at risk of loss of stony coral tissue. This disease has engulfed Florida and the Caribbean, causing massive deaths.

In two years, the researchers rescued 980 corals, called naive corals, before the disease infected them.

“Initially, efforts focused on collecting corals ahead of the moving disease front, getting them out of the oceans, and preventing them from being affected by the disease,” said Dr. Abby Renegar, a researcher-scientist who worked on the project.

Now the researchers have moved more towards preserving corals more generally, including corals that have survived disease. They study and propagate those corals in the hope that their genotype will breed more disease-resistant corals.

“We’ve shifted our focus a bit with the ability of the nursery that was established during the initial response to stony coral tissue loss disease to provide a home for endemic corals for many different reasons,” Renegar said.

The NSU nursery has produced 3,605 fragments of coral in the past year, a third of which have been returned to the reefs.

Some corals, such as the corals that NSU received during the Noah’s Ark project, will not be planted. Instead, they are kept in labs or aquariums, or studied for research. Pisano said they act partly as a seed bank.

One of the most impressive specimens at the nursery is a meter-wide brain coral that the researchers estimate is about 150 years old, said NSU graduate student Katrina Smith. They’re waiting for another expert to give the exact age, and when they do, they can break it down into smaller pieces, essentially in a small-scale cloning process.

Once the researchers decide a coral will be fragmented, they often use a band saw or tile saw to split it into pieces, making sure to protect the coral as much as possible. The specimens then go into large tanks, where they are given artificial salt water that is mixed on site with salt from their 900-pound barrels. If the corals need additional nutrients, the nursery researchers can sprinkle a plankton mixture over the coral with a turkey baster.

Many corals must be quarantined for 30 days after arrival if not planted out immediately, and they will require veterinary checks if they are in the facility long enough. These corals are being studied and documented, and many are returning to offshore reefs.

According to the Environmental Protection Agency, 25% of marine life depends on coral reefs at some point in their lives. Reefs are vital in medical research, generating tens of billions of dollars worldwide from diving, fishing and tourism. They also serve as barriers against storms.

Coral is in danger in NSU’s backyard. Smith estimates that approximately 40,000 corals in Port Everglades are at risk from the construction of the harbor intended to deepen and widen it. Some of these corals will probably go to NSU’s nursery, but it can’t house 40,000 corals. Bigger solutions are needed, Pisano said, and he thinks they will happen in time.

“I think it will always be a struggle, and there will always be resistance because environmental mitigation is expensive,” Pisano said. “It takes time, it takes people, it takes effort. But I think we’ll get there eventually.”

With disease, ocean acidification, water quality problems and ocean warming among other factors, Renegar said it can be difficult to pinpoint exactly what is causing die-offs. That can make creating solutions more challenging, but the team is doing what they can to conserve coral with what they have.

“A lot of what we do isn’t necessarily just band aids for the situation,” said Matthew Rojano, a graduate student working on the project. “They’re pretty helpful in preserving the genetic pool that these corals reproduce. But if you don’t fix the underlying issues, it won’t really do much good to bring them back.”

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2022 South Florida Sun Sentinel. Distributed by Tribune Content Agency, LLC

Quote: Researchers’ ocean nursery hosts thousands of at-risk corals (2022, June 27) retrieved June 28, 2022 from https://phys.org/news/2022-06-oceanside-nursery-home-thousands-at-risk.html

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