Scientists working with the National Oceanic and Atmospheric Administration (NOAA) recently discovered a previously unknown coral reef off the US East Coast.

The 85-mile-long deep-sea reef is located approximately 160 miles east of Charleston, South Carolina.

Previous research pointed to the existence of the reef, but it had never been seen firsthand until last month.

The seafloor is one of the last unexplored regions of our watery planet.

On a recent expedition dubbed Deep Search 2018, a group of ocean researchers discovered 85 miles of deep-sea coral reef off the coast of the southeastern US.

"Good news is too rare these days, and this is a victory that we can all share. We have found a pristine coral reef in our own backyard," Erik Cordes, the chief scientist on the expedition and a deep-sea ecologist at Temple University, wrote in a mission summary.

Deep Search 2018, which took place from August 19 to September 2, was a collaborative project between the National Oceanic and Atmospheric Administration (NOAA), the Bureau of Ocean Energy Management, and the US Geological Survey. The goal of the expedition was to research — and safeguard — the little-understood habitats lurking off the US's populated East Coast. To collect new information about these deep-water habitats, scientists used a research ship called Atlantis from the Woods Hole Oceanographic Institution.

"We completed 11 dives in the human occupied vehicle (HOV) Alvin in the turbid parts of canyons, stunning cliff faces, bubbling gas seeps, and massive deep-sea coral reefs," Cordes wrote. "The information we have gathered will help us to understand these habitats and their dynamics."

Human Occupied Vehicle Alvin, which is operated by Woods Hole Oceanographic Institution, has been in operation since 1964. Courtesy of Woods Hole Oceanographic Institution

But by far the biggest outcome of the mission, he said, was the discovery of the previously unknown reef. Cordes and expedition members first spotted the reef during an eight-hour dive on August 23. Cameras on the submersible Alvin captured live corals perched on large mounds of dead corals, indicating that this community has been thriving for centuries.

The 85-mile reef is located off the coast of Georgia and South Carolina, approximately 160 miles east of Charleston. The corals were mostly Lophelia, a variety of deep-sea corals that grow in cold, Atlantic waters. Along with Lophelia, the team brought back samples of other coral varieties as well, including octocorals.

"Many members of the Deep Search team will spend the coming months and years fully characterizing the significance of our August 23 dive, which revealed extensive, previously unconfirmed Lophelia reefs," the researchers wrote in a blog post following the discovery.

Scientists knew from past research carried out by NOAA that deep-sea coral mounds existed in these waters, but they had never viewed the reefs firsthand.

Thriving Lophelia pertusa reefs were found in a region further offshore and in deeper water than other known Lophelia reefs in the US Atlantic. Courtesy of Dan Fornari, Woods Hole Oceanographic Institution

The Deep Search team created a three-minute time-lapse video of the eight-hour dive in which they discovered the coral reef. You can watch the footage here.

Researchers will use the samples they collected to better understand these teeming deep-sea communities. Cordes told HuffPost the reef provides important habitat for a number of fish and coral species.

But President Donald Trump's Administration has proposed rolling back bans on offshore oil drilling in the Atlantic, which could potentially impact this reef, according to a report from The Atlanta Journal-Constitution.