An interdisciplinary team of scientists led by scientists from Utrecht University with participation from University of Gothenburg have found new clues about how deep life may extend into the Earth's interior near the deepest place on our planet – the Challenger Deep in the Pacific Ocean. In their paper published in the Proceedings of the National Academy of Sciences, they examine complex organic molecules that have been trapped within rock fragments brought to the seafloor by massive mud volcanoes.

[...] In their hunt for tell-tale signs of life, the scientists have analysed rock fragments that have been carried by the mud volcanoes from as deep as 20 km within the Earth. Using state-of-the-art analytical techniques they found organic matter encapsulated within the clasts. [...] Although Dr. Plümper and his colleagues cannot pinpoint the exact origin of the organic matter, chemical analysis of the constituents hint at microbial life deep within or below the mud volcano. This is consistent with calculations conducted by the authors using the currently known temperature limit for life, 122 °C, and the temperatures expected under the mud volcanoes, which suggest that life could exist as deep as 10,000 meters below seafloor. This is considerably deeper than other serpentinizing regions such as mid-ocean ridges and could have provided a sheltered habitat for life helping it to survive the more violent phases of Earth's early history.