Mariana microbes: Signs of life discovered at deepest point on Earth - study
Scientists have unearthed rock fragments containing organic matter six miles below the Mariana trench, presenting the possibility that this could be the deepest microbial life ever found on Earth.
The fragments were brought to the sea floor by massive mud volcanoes near the Mariana trench - the deepest place on the planet. If scientists confirm evidence of microbial life in the material it will triple the previous estimated depth limit for life within the Earth’s mantle.
Het onderzoeksteam vond voor het eerst organisch materiaal; bewijzen van leven, in gesteente van zo’n twintig kilometer diepte pic.twitter.com/TH1RsPc1za— Universiteit Utrecht (@UniUtrecht) April 11, 2017
A team of scientists lead by Oliver Plümper, a researcher at Utrecht University in the Netherlands, published their findings in the Proceedings of the National Academy of Sciences. During an analysis of the mineral-rich mud, the team did not find intact microbes but did observe traces of organic material.
Hydrocarbons, lipids, and amino acids were found in 46 rock samples drilled from the mud volcano chemicals associated with bacterial waste products, reported Science Alert.
“This is another hint at a great, deep biosphere on our planet," Plumper told National Geographic. “It could be huge or very small, but there is definitely something going on that we don’t understand yet.”
Dr Ivan Savov from the University of Leeds, who also worked on the research, added in a statement that the findings reveal a “new insight into the habitability of the planet.”
“Given the difficulty of obtaining samples from the deep earth, there have not been many opportunities to explore how microbial life can be supported in the absence of photosynthesis,” Savov explained. “The mantle rocks we studied give us a link between the deep carbon cycle and the surface world.”
While the scientists admit the source of the organic chemicals is not clear, they say there is a possibility of life at this depth given the currently known temperature limit for life of 122°C and the likely temperatures under the mud volcanoes.
One possibility the researchers suggest is that the depth provided a sheltered habitat, allowing life to survive there during the “more violent phases of Earth’s early history.”
The Mariana Trench, located in the western Pacific ocean, is part of the Izu-Bonin-Mariana subduction system that forms the boundary between two tectonic plates. In the film 2012, director James Cameron made the first solo journey to the trench’s deepest point, the Challenger Deep, following in the footsteps of the manned descent by the Trieste in 1960.