Scientists have discovered large amounts of microscopic life at the bottom of the Mariana Trench, the deepest location on Earth.
The scientists' study, published in the journal Nature Geoscience, describes the discovery of a thriving community of microbes located at the bottom of the trench, nearly seven miles deep in the Pacific Ocean. It was previously believed that the Mariana Trench's environment was too hostile to support life. The new study, however, suggests otherwise and contributes to mounting evidence that a large number of creatures can survive in environments that are highly pressurized, completely dark and almost freezing.
"The deepest parts of the deep sea are certainly not dead zones," Robert Turnewitsch, co-author of the study from the Scottish Association for Marine Science, said.
The study goes back to 2010, when the scientists sent an unmanned robot into the canyon to collect sediment samples from the ocean floor. After examining oxygen levels in the sediment, the researchers found a large microbe population.
"These microbes, they respire as we do," Turnewitsch says. "And this oxygen consumption is an indirect measurement of the activity of the community."
Interestingly, they found that there was about ten times more bacteria at the bottom of the trench than in the surrounding waters. This could be explained by a large amount of dead plants and creatures that had sunk down to the bottom of the trench from the surface. The microbes then feast on the dead refuse.
"The amount of food down there and also the relative freshness of the material is surprisingly high - it seems to be surprisingly nutritious," Turnewitsch says.
The microbial presence in the trench, part of an area called the Hadal zone, may even have implications for the carbon cycle and, accordingly, regulation of Earth's climate.
"The fact that large amounts of organic matter that contain the carbon accumulate and are focused in these trenches also means they play an important role in the removal of carbon from the ocean and the overlying atmosphere," Turnewitsch says. "The Hadal trenches may play a more important role in the global marine carbon cycle than was previously thought."
The Mariana Trench is of such interest that even director James Cameron took a peak. In 2012, Cameron became the first person to visit the trench in 50 years, diving to the bottom himself in a one-man-submarine. Afterward, he told the BBC that it was an "alien and barren terrain." Footage of the plunge will be released by National Geographic as a 3D documentary.
