Unusual sea creatures found in Earth's 'last frontier'

Published On: Aug 06 2014 03:15:38 AM HST   Updated On: Jun 25 2014 07:54:09 PM HST

They used an unmanned sub called Nereus instead of a spaceship, but make no mistake, researchers who studied the Kermadec Trench earlier this year were staring at the great unknown.

Click here to watch Andrew Pereira's report.

"It's definitely the last frontier on the planet," said Jeffrey Drazen, an associate professor of oceanography at UH Manoa. "It was amazing to see these places that no one has laid eyes on berfore."

The Kermadec Trench off the northeastern tip of New Zealand's North Island is the fifth deepest trench in the world with a depth of 6.2 miles. The goal of the expedition, known as the Hadal Ecosystem Studies or HADES, is to study creatures that have adapted to the extreme pressure as well as the 34 degree water. The voyage was led by deep-sea biologist Tim Shank of the Woods Hole Oceanographic Institution.

Drazen said several new species were discovered, including a coral-like creature with eight arms and no exoskeleton. HADES is withholding all video and pictures of the unusual animal until a later date.

During the 30-day expedition that began April 10, researchers also gathered dozens of samples of already-known animals like the snailfish, the deepest known fish in the ocean that can withstand the crushing pressure of 1,000 atmospheres.

"Some of these animals may have compounds that they use to deal with pressure that can be very important to industrial or bio-medical applications, and we need to sort of understand how they function and which compounds they use before we get to that stage, but if we never do this, we'll never know," Drazen explained.

However, where food is obviously scarce, the key to survival appears to be detritus from once living organisms like plankton. The material gathers on the deep-ocean floor as a light-grey substance, also known as marine snow, which can be several feet deep.  

"The trench is very steep-sided, and so this stuff just rolls downhill," said Drazen. "Once it reaches the sea floor, it's enriching the sediments there."

Researchers were amazed when they reached the bottom of the Kermadec Trench and immediately noticed animal tracks at nearly every location where they pointed their cameras.

"So it was very fine mud and it was just crisscrossed," said Drazen. "Imagine a kid taking a piece of paper and drawing squiggly lines all over it -- that's what the seafloor looked like, every square meter."   

The HADES expedition also set out bait traps with cameras at varying depths to see what kind of creatures would gravitate toward the large pieces of tuna. Amazingly at six miles down, cusk eels simply moved toward the free meal and waited to feed upon smaller animals. But by far, the most active creatures were shrimp-like animals that live on the ocean bottom.

"Very rapidly all of these little shrimp-like crustaceans called arthropods come up out of the mud, swim in from the sides into the field of view, and start feeding on the bait," said Drazen. "At the shallower depths, down to about a little more than 7,000 meters (4.3 miles), you see fishes and shrimps as well. They're actually gone at the greater depths."   

Although the expedition gathered an abundance of data and specimens that could take months if not years to sort through, researchers suffered a major setback when the Nereus was destroyed more than six miles beneath the surface. Researchers believe one of the sub's two air-filled housings suddenly collapsed.

"When that happens you have an airspace going from one atmosphere to 1,000 atmospheres in a tiny fraction of a second, and that shock wave is like a stick of dynamite going off," said Drazen. "It is in many little pieces."   

Despite the loss of the $8 million submarine, researchers plan on revisiting the Kermadec Trench in about two years.
"We got about half of the stations sampled that we wanted to get sampled," said Drazen. "We'll go ahead and learn as much as we can without the Nereus vehicle until we have its replacement."

Anyone wanting to contribute funds to the next expedition can contact the University of Hawaii Foundation at www.uhfoundation.org, or the UH School of Ocean and Earth Science and Technology at www.soest.hawaii.edu.


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