Marine researchers have just returned from a trip to the Northwestern Hawaiian Islands with tales of previously unknown, "absolutely bizarre sponges" — with one resembling the "Alien" of science-fiction movie fame.

The unique marine life was discovered earlier this month in ocean waters nearly a mile deep in areas known as Middle Bank and Twin Banks near Nihoa Island, northwest of Kaua'i.

Christopher Kelley, program biologist for the Hawai'i Undersea Research Laboratory, got a tremendous kick not just in discovering the previously unknown life forms but in filming them in high-definition video.

"We came back with high definition for the first time — it's the closest thing we can provide to show people what it's like looking out the window of a submersible," Kelley said. "The biggest thing for me is to try to show all these animals to other people."

Operating off the University of Hawai'i's research vessel Ka'imikai-o-Kanaloa, and using the submersibles Pisces IV and Pisces V, the scientists found a bonanza of unknown sea creatures just inside the eastern boundary of the Papahänaumokuäkea Marine National Monument.

While the sponges that look like "Alien" — or something out of a "Dr. Seuss" drawing — are the headline grabbers, Kelley was intrigued by another huge sponge whose brilliant white color changed to a tinge of red in the precise area where the submersible had clipped a tissue sample.

"Of course, sponges have no blood," Kelley said. But whether the sponge was indicating it had been injured or felt pain in the area from which the sample was plucked remains to be seen.

It was, Kelley said, a startling reaction from a creature that has no brain and no central nervous system.

It is far too early to say what the discovery will mean, Kelley said. But in the past, marine creatures have been found to have an "incredible array" of medicinal qualities, he said.

Travel time from Snug Harbor near Sand Island to the dive sites is about 30 hours. The latest research trip was designed specifically to look for deep-ocean coral and sponges.

Some of the largest sponges, which are stationary creatures fixed to the ocean bottom, were found growing from a ridge above a deep ocean canyon. They were in an area of relatively fast-flowing current. Kelley said he believes that fast-flowing water brings plenty of plankton and other nutrients to the sponges that filter ocean water for sustenance.

Max Cremer, who helped pilot the two submersibles on the trip, said it takes the deep-sea diving machines about 90 minutes to descend a mile down where the sponges were found.

In addition to the pilot, who must spend the entire dive on his knees, there is room for two other researchers, who have to dress warmly. The temperature inside drops to the upper 40s, Cremer said.

The Pisces IV, which is now 27 years old, is rated for 100,000 dive cycles. It has logged about 5,000 overall, about 250 since moving to Hawai'i from Canada.

While aboard the dive vessel, crew members breathe normal air, which is maintained at the same pressure found on the ocean surface.

Leaks are extremely rare, but are an obvious cause for alarm.

"During the descent on deep dives, it's not uncommon for condensation to form on the submersible walls," Cremer said. "The crew frequently touch a finger to the wall and then put it against their tongue to taste for salt."