Life in the Mariana Trench

The Mariana Trench is the deepest part of the of the world’s oceans, at a maximum known depth of 10.9 kilometres. From Wikipedia: “If Mount Everest, the highest mountain on Earth at 8,850 metres (29,040 ft), was set in the deepest part of the Mariana Trench, there would be 2,060 metres (6,760 ft) of water left above it.” 

Most importantly, “At the bottom of the trench, where the plates meet, the water column above exerts a pressure of 1,086 bars (15,750 psi), over one thousand times the standard atmospheric pressure at sea level.” That, and the fact that light won’t reach that depth, means that life in the Trench (we’re buddies, I can call it “the Trench”) is very different from life as we know it near sea level, as well as difficult to observe. Yet observe it we have.

From LiveScience:

Gigantic amoebas have been found in the Mariana Trench, the deepest region on Earth.

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.

For reference, the average human cell is about ~10 µm in diameter; that means these amoeba’s cells are 10,000 times the size of ours. That’s a big cell.

The researchers spotted the life forms at depths up to 6.6 miles (10,641 meters) within the Sirena Deep of the Mariana 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 xenophyophores are just the tip of the deep-sea ecosystem iceberg. The expedition also found the deepest jellyfish observed to date, as well as other mysterious animals.

As I’ve said before, finding new species in novel environments like this is important – discoveries could have all kinds of applications. So little of the ocean has been explored that I’m sure there will be many, many discoveries to make in the future.


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