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A Single-Celled Organism
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The giants of the deep are so-called xenophyophores, sponge-like animals that—like amoebas—are made of just one cell. They were found during a July research expedition run by the Scripps Institution of Oceanography in La Jolla, California.
The animals are about four inches (ten centimeters) long—among the largest single-celled organisms known to exist.
The creatures were discovered at depths of 6.6 miles (10.6 kilometers). That breaks a previous record for xenophyophores found in the New Hebrides Trench at 4.7 miles (7.6 kilometers).
Xenophyophores represent, <u>"one of the few groups of organisms found exclusively in the deep sea,"</u> said Lisa Levin, a Scripps oceanographer who studied the expedition's data.
<u>"If any creatures should be able to live at the ocean's greatest depth, then xenophyophores certainly should be among them."</u>
The Mariana xenophyophores were seen in footage from Dropcams, free-falling devices equipped with lights and digital video that were developed by the National Geographic Society. (The Society owns National Geographic News.)
Protected by thick walls of pressure-resistant glass, the Dropcams were baited to attract whatever marine life might be lurking in the deep. Expedition scientists also saw, for instance, the deepest-swimming jellyfish to date. (Watch a video of the expedition.)
<u>"The deep sea is the largest biome on Earth and holds much of the diversity on the planet—[yet it's still] largely undescribed,"</u> Levin said in an email to National Geographic News.
(Also see, <u>"Pictures: Hard-to-See Sea Creatures Revealed."</u>)
According to Jon Copley, a marine biologist at the U.K.'s University of Southampton, <u>"many of the major discoveries in deep-sea biology have come from making direct observations at the seafloor."</u>
<u>"The Dropcam is a great tool for the future, because it can help us see more of what's down there for less cost than using ROVs or submersibles,"</u> he said via email.
For instance, <u>"finding xenophyophores far deeper than before shows how much we still have to learn about our oceans depths and their inhabitants."</u>
Tullis Onsott, an expert in deep-sea microorganisms at Princeton University, also called the xenophyophore discovery, <u>"fantastic."</u>
