Deepest ocean trench home to race of giant amoebas
Scientists have discovered a community of 4-inch amoebas living at the bottom of the Mariana Trench, the deepest known part of the world's oceans.
During a July 2011 voyage to the Pacific Ocean chasm, researchers with Scripps Institution of Oceanography at UC San Diego and National Geographic engineers deployed untethered landers, called dropcams, equipped with digital video and lights to explore the largely mysterious region of the deep sea.
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 4 inches (10 centimeters), their extreme abundance on the seafloor and their role as hosts for a variety of organisms.
Extreme environment, extreme creature
The researchers spotted the life forms at depths up to 6.6 miles (10,641 meters) within the Sirena Deep of the Mariana Trench. The previous depth record for xenophyophores was approximately 4.7 miles (7,500 m) in the New Hebrides Trench, although sightings in the deepest portion of the Mariana Trench have been reported. [Infographic: Tallest Mountain to Deepest Ocean Trench]
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 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 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," said Doug Bartlett, the Scripps marine microbiologist who organized the expedition.