Researchers Identify Mysterious Life Forms in the Extreme Deep Sea [View All]

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ScienceDaily (Oct. 24, 2011) — A summer research expedition organized by scientists at Scripps Institution of Oceanography at UC San Diego has led to the identification of gigantic amoebas at one of the deepest locations on Earth.

During a July 2011 voyage to the Pacific Ocean's Mariana Trench, the deepest region on the planet, Scripps researchers and National Geographic engineers deployed untethered free-falling/ascending landers equipped with digital video and lights to search the largely unexplored region. The team documented the deepest known existence of xenophyophores, single-celled animals exclusively found in deep-sea environments. Xenophyophores are noteworthy for their size, with individual cells often exceeding 10 centimeters (4 inches), their extreme abundance on the seafloor and their role as hosts for a variety of organisms.

The researchers spotted the life forms at depths up to 10,641 meters (6.6 miles) within the Sirena Deep of the Mariana Trench. The previous depth record for xenophyophores was approximately 7,500 meters (4.7 miles) in the New Hebrides Trench, although sightings in the deepest portion of the Mariana Trench have been reported. Scientists say xenophyophores are the largest individual cells in existence. Recent studies indicate that by trapping particles from the water, xenophyophores can concentrate high levels of lead, uranium and mercury and are thus likely highly resistant to large doses of heavy metals. They also are well suited to a life of darkness, low temperature and high pressure in the deep sea.

"The research of Scripps Professor Lisa Levin (deep-sea biologist) has demonstrated that these organisms play host to diverse multicellular organisms," said Doug Bartlett, the Scripps marine microbiologist who organized the Mariana Trench expedition. "Thus the identification of these gigantic cells in one of the deepest marine environments on the planet opens up a whole new habitat for further study of biodiversity, biotechnological potential and extreme environment adaptation."

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http://www.sciencedaily.com/releases/2011/10/111024165037.htm