Scientists have found an active coral community that may belong to a deep-sea coral reef system presumed to be dead decades ago, according to new research.
A living coral garden, located off the coast of Benin, West Africa, about 54 meters -- or 177 feet -- below the surface of the Gulf of Guinea, was detected using sonar technology and deep-sea cameras, according to a paper published earlier this week in the journal Frontiers in Marine Science.
In the 1960s, Benin's government funded researchers to study what kind of fish species existed in the region, which also included investigation into the seabeds and hydrology, Gerard Zinzindohoue, a scientist at the Benin Fisheries and Oceanological Research Institute and lead author of the paper, told ABC News.
The researchers were able to gather a sample of a coral reef, but a possible reef system was assumed to be dead since its ecological status remained unknown, according to the paper. And because the focus of the study was not the corals themselves, only a short paragraph was written into the 100-page report, Zinzindohoue said.
But that determination wasn't enough to quell Zinzindohoue's curiosity, he said.
"One hope is that even though the reef is dead, it might still be important for the microorganisms living at that ecosystem."
This time, researchers were equipped with modern technology. They first used a side-scan sonar, a sensing system used to detect and image objects on the seafloor.
At first, they only picked up rocky sediment on the seafloor. But once they sensed a rocky structure, they deployed the National Geographic Deep Sea Camera System, which provided close-up evidence of the ecosystem observed on the sonar image, Zinzindohoue said.
For an even closer-up view of the ecosystem, the researchers used an underwater drone. They saw multiple species of coral moving through the current and a plethora of fish surrounding the reef structures, Zinzindohoue said, describing the scene as a "really undisturbed environment."
"Everything was alive," Zinzindohoue said. "And it was a really big moment for us because it was some things we have never seen."
The assemblage included six octocorals -- a type of soft coral -- and two types of black corals -- which formed a coral garden, rather than a structured reef, according to the paper. At least eight associated reef fish species were identified as well.
In addition, the researchers did not observe any bleaching within the reef system, Zinzindohoue said.
This is the first confirmed existence of a mesophotic coral reef system -- or a reef system that requires light to survive but lives in deeper waters where sunlight isn't as available -- in the continental shelf of the Gulf of Guinea, Zinzindohoue said.
Mesophotic coral ecosystems along the West African coastline, particularly on the Gulf of Guinea's continental shelf, remain poorly documented, according to the paper.
The next steps will be to collect samples from the reef to further investigate its current state, Zinzindohoue said.
No physical samples have been taken so far, and the idea of a long uninterrupted coral barrier "is not supported" by the acoustic data gathered for the study, according to the paper.
It will be important to study these reefs and their resiliency going forward, especially in the face of climate change and marine warming threatening reefs all over the world, Zinzindohoue said.
"Today, in any ocean around the world, and particularly in West Africa and Benin, we experience climate change effects," he said. "So we really want to continue to investigate."
