Astonishing microbial biodiversity discovered beneath Earth's surface
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Scientists have found an astonishing diversity of microbial life thriving deep beneath Earth's surface.
Led by Emil Ruff, an associate scientist at the Marine Biological Laboratory (MBL), the research explores ecosystems as deep as 491 meters below the seafloor and 4,375 meters underground, revealing subsurface biodiversity comparable to that of tropical rainforests and coral reefs.
Findings may have implications for extraterrestrial life and cellular adaptations in extreme conditions.
The study emphasizes the resilience of microbes, particularly those in the Archaea domain, which flourish in extreme, low-energy environments. According to Ruff, some deep subsurface habitats even surpass surface ecosystems in biodiversity, challenging assumptions about the energy limitations in such isolated conditions.
This research is among the first to compare microbial diversity in marine and terrestrial subsurface ecosystems. While diversity levels are similar, the microbial communities differ significantly between land and sea due to unique environmental pressures. These distinctions underline the adaptability of microbial life and its ability to specialize within specific realms.
The study estimates that 50-80% of Earth's microbial cells exist beneath its surface, enduring minimal energy availability. Some cells divide as infrequently as once every 1,000 years, offering critical insights into cellular efficiency, aging, and survival strategies in extreme conditions.
The findings also have implications for the search for life on Mars. Ruff suggests that rocky subsurface environments on Mars might mirror those on Earth, providing a valuable model for exploring the potential for past or existing life on the Red Planet.
A uniform DNA sequencing protocol was key to the study’s success, enabling comprehensive comparisons across over 1,000 samples from 50 ecosystems. Co-first author Isabella Hrabe de Angelis from the Max Planck Institute for Chemistry contributed bioinformatics expertise to the project, which Ruff credits for enhancing the study’s depth and reliability.