Best News: Sea sponge the size of a minivan discovered in ocean depths off Hawaii

Scientists find immense creature 2,100m below surface of the ocean
Researcher: 'It's probably in the order of centuries to millennia old'

Scientists discover gigantic sea sponge in Hawaii

Deep sea scientists exploring the remote waters between Hawaii and Midway atoll have found a gigantic sea sponge "about the size of a minivan" that could be the oldest animal on earth.

"It's probably on the order of centuries to millennia old," lead researcher Daniel Wagner told the Guardian. The sponge, the largest on record, is "about 12ft wide and 7ft long" he said, "so about the size of a minivan".

The creature was discovered about 2,100m (7,000ft) down, in a marine conservation area between north-western Hawaii and Midway. The area is largely unexplored, Wagner said, and "over 98% of the area of this monument is below 100m, so below something that we would ever be able to dive through with scuba diving".

A remote-operated submersible found the sponge while exploring the depths of the Papahānaumokuākea marine park. Cast into the sub's lights, the sponge's brain-like folds appear in a pale, nearly white shade of blue.

Scientists described the animal this week, in the journal Marine Biodiversity.

Wagner said they could not be sure of the sponge's age, since the animals lack growth rings found in corals that are similar to terrestrial trees.

A team of scientists on a deep-sea expedition discovered the sponge, which they say is the world's largest ever documented. — A team of scientists on a deep-sea expedition discovered the sponge. Photograph: AP

"Corals in similar environments have made it for 4,000 years," he said. Through measuring the rate of growth in sponges over decades, he added, "we also know that giant sponges in shallow waters can make it more than 2,000 years."

Wagner also noted that most of the planet "lies in deep waters, the vast majority of which has never been explored", and that "7,000 marine species, a quarter of which are found nowhere else on the planet" are known to live in Papahānaumokuākea marine park alone.

"This one expedition itself came back with over 100 new species," he said, speaking of completely new species and life previously unknown to the region. "So there's probably many, many other things down there."

The "pristine" depths, Wagner said, included large communities of sponges and corals along with "a whole bunch of things that are associated with them: fish hiding in their crevasses, you got crinoids , barnacles, all kinds of things that grow on top of these sponges and corals. It's really a very diverse community."

Like the coral reefs they often grow alongside, sponges are "habitat forming" species, providing shelter, filtering sea water and removing material in the water that other animals do not eat. Sponges are ancient but primitive: they lack nervous or digestives system and rely on water flowing through their bodies to provide sustenance and clean them of waste.

Christopher Kelley, a biologist at the National Oceanographic and Atmospheric Administration (NOAA) Hawaii undersea research lab, said the researchers used laser points to measure the dimensions of the bulbous animal, then compared them with the size of the submersible.

Sponges are similar to coral reefs in that they provide critical habitat for other sea life. Photograph: AP

He added that sponge experts have so far been unable to identify the animal's genus.

"Here's this animal that has presumably never been encountered before and it's enormous and that kind of brings up a little intrigue for deep water and what else exists down there," he said.

At more than 140,000 square miles, the Papahānaumokuākea marine park is the largest conservation area in the US, and larger than every other US national park combined.

Joseph Pawlik, a marine biologist at the University of North Carolina, Wilmington, said measuring the size of sponges can be difficult, given their serpentine shape and peculiar structures. By studying large barrel sponges, Pawlik has devised a method to estimate age and size based on volume.

"Largest implies volume," he said. "We have some pretty substantial sponges that are barrel sponges that have huge volume."