A hotspot of ocean life has been discovered off the southernmost tip of mainland Australia, hiding on the sea floor hundreds of feet below the surface. Located within Wilsons Promontory Marine National Park in Victoria, the beauty and biodiversity of this place is so extreme it reportedly rivals the world-famous Great Barrier Reef.

The park is only about a two-hour drive from Melbourne, a city of 4 million people, yet the ecological bounty of its seabed has remained mostly unknown until now. After previous research mapped out the park's sea floor in detail, researchers made the new discovery by sending down a remotely operated vehicle (ROV) to explore its marine life between 100 and 330 feet (30 to 100 meters) deep.

"The maps identified some amazing underwater structures very deep beneath the ocean, but we did not know what sort of marine life was there," Parks Victoria marine science manager Steffan Howe says in a press release about the discovery. "These latest expeditions used cutting-edge technology including underwater video cameras and a robotic vehicle to record the spectacular marine life found in many of the deeper areas of the park for the first time."

The resulting footage "shows that the deep reef habitats are teeming with life and are home to rich and abundant marine ecosystems that are comparable to Australia's better-known tropical reef areas," Howe adds. "The extent and abundance of spectacular sponge gardens and corals is a particularly exciting find."

The park is located on Wilsons Promontory, a peninsula that juts into Bass Strait and is part of an ancient land bridge that once connected Australia to Tasmania. The seabed features extensive walls, house-sized boulders, ridges and caverns, the researchers say, as well as complex underwater dune systems, including one that measures about 100 feet (30 meters) high and 1.25 miles (2 kilometers) long.

But its most impressive aspect is the rich ecosystem it hosts. In addition to the sponge gardens — which alone may represent a global hotspot of biodiversity, the researchers say — the area's highlights include massive coral fans, large sea whips and a rich variety of fish, including some rare species "of conservation significance" like the Australian barracuda and longsnout boarfish. Some of the wildlife is hidden even deeper than the seabed, such as large schools of deep-sea perch found in holes stretching nearly 300 feet (90 meters) deep.

"We were blown away," marine biologist and ROV operator Matt Edmunds tells The Age newspaper. "We wear virtual-reality goggles, so you kind of feel like you're part of the ROV when you're piloting it. You feel like you're down there."

"We discovered quite a few different community types that we didn't even think existed out there, in terms of sponge gardens and coral assemblages," Edmunds adds. "In some of the deep sediment scour holes we discovered things like big cup or plate sponges that we'd never seen in Victoria before."

Wilsons Promontory Marine National ParkPhoto: Parks Victoria

The researchers are still examining imagery from the ROV, and Howe tells the Huffington Post it "will take some time" before they can identify everything the vehicle recorded. "But given the diversity of the marine life we've seen," he adds, "I wouldn't be surprised if there were some species that we haven't seen before."

The enormous Great Barrier Reef attracts more than 2 million visitors to the coast of Queensland every year, and this discovery may similarly inspire an eco-tourism boom for the already-popular Wilsons Promontory. But as Howe notes in the press release, scientists must first figure out what's down there to determine what dangers people might pose to the ecosystem and what kinds of protection are needed.

"It is important for us to have a comprehensive understanding of the habitats and inhabitants in Wilsons Promontory Marine National Park to help guide how we manage this important area in the future," Howe says. "The discoveries and footage will also enable us to showcase Victoria's spectacular marine environment to the thousands of visitors who come to this park each year."

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.

New seabed discovery rivals Great Barrier Reef
An expedition to the sea floor off Australia's southern coast has revealed an underwater Eden, scientists say.