February 3, 2012
Researchers Find King-sized Crustacean In Deep Pacific Trench
During an expedition to the Kermadec Trench north of New Zealand in the Pacific Ocean researchers discovered a ℠supergiant´ amphipod measuring 10 times the size of typical amphipods.
Typically deep sea amphipods are about an inch long (2-3 centimeters) with the exception of the ℠giant´ amphipod found in Antarctica which can be up to 4 inches long (10 centimeters). But the latest discovery, in the world´s deepest ocean at depths of 23,000 feet, measures an astonishing 13.4 inches long (34 centimeters).Amphipods are a type of crustacean that are common in deeper waters and are found in greater numbers deeper down. The creatures are typically small, but extremely active, and seem to thrive in places where pressure is one thousand times greater than at sea level.
The supergiant amphipods were discovered by scientists from the University of Aberdeen, Scotland and Wellington´s National Institute of Water and Atmospheric Research (NIWA).
“It´s a bit like finding a foot-long cockroach,” said Alan Jamieson, from University of Aberdeen´s OceanLab. “I stopped and thought: ℠What on Earth was that?´ This amphipod was far bigger than I ever thought possible.”
The researchers found the oddly-sized animals using a large metal trap, which was equipped with a camera, housed in sapphire glass to keep it safe from the high pressure in the deep waters. Seven specimens in all were caught in the trap, and nine more were captured on film. The largest amphipod caught was 11 inches long, but the team observed larger ones on camera during the dive.
The goals of the researchers on the expedition were to find and catch specimens of deep sea snailfish which have been photographed before, but have not been captured since the 1950s. Jamieson said his team was “elated at the sight of the snailfish as we have been after these fish for years.”
But they didn´t expect to find and catch these supergiant amphipods, which haven´t been seen since large specimens were caught off the coast of Hawaii in the 1980s. And even those ones paled in comparison to these new discoveries. These new sightings and specimens captured represent both the biggest whole specimen of supergiant ever caught and the deepest point these have ever been found.
“It just goes to show that the more you look, the more you find,” said Dr. Ashley Rowden, from NIWA. “For such a large and conspicuous animal to go unnoticed for so long is just testament to how little we know about life in New Zealand´s most deep and unique habitat.”
“The surprising thing is that we have already been to this deep trench twice and never come across these animals before,” Jamieson added. “In fact a few days after the discovery we deployed all the equipment again on the same site and we didn´t photograph or capture a single supergiant; they were there for a day and gone the next.”
The team will now take on the challenge of determining whether these new samples are the same species as those from Hawaii, and then establish why, out of hundreds of species of deep-sea amphipods, these ones have evolved to be so large.
The team also discovered shrimp-like creatures called isopods at depths more than 25,000 feet deep.
The expedition was chiefly funded by the Foundation Total in France, with additional funding from NIWA and support from the Marine Alliance for Science and Technology, Scotland (MASTS).
Image caption: Photo of the supergiant amphipod. Photo copyright of Oceanlab, University of Aberdeen, UK.
On the Net: