A landmark global study published in Science Advances has revealed the extraordinary diversity of microbial life thriving beneath the Earth’s surface. Conducted by a team led by Emil Ruff, Associate Scientist of the Marine Biological Laboratory (MBL), this research provides new insights into the life forms living at depths of up to 491 meters below sea level and up to 4,375 meters underground. According to the study, these subsurface ecosystems rival the biodiversity found on Earth’s surface, which has implications for areas such as bioprospecting, cellular adaptation to low-energy environments, and the search for extraterrestrial life.
Microbial diversity in depth
The study highlights the ability of microbes in the Archaea domain to thrive in these extreme conditions, with some subsurface environments displaying biodiversity comparable to tropical forests or coral reefs. Speaking to the publications, Ruff explained that contrary to assumptions about energy limitations at great depths, some subsurface habitats surpass surface ecosystems in diversity.
Comparison of marine and terrestrial microbiomes
Ruff’s team conducted the first comparison of microbial diversity between marine and terrestrial regions, revealing vast differences in composition despite similar diversity levels. According to Ruff, these findings suggest that selective pressures specific to land and sea create distinct microbial communities that are unable to thrive in the opposite region.
slow life
Reports indicate that an estimated 50–80 percent of Earth’s microbial cells exist in the subsurface, often in conditions where energy availability is minimal. Some cells divide once every 1,000 years, providing valuable insights into how to survive in low-energy environments. Understanding these adaptations could help future studies on cellular efficiency and aging, Ruff said.
Implications for extraterrestrial research
The study also draws parallels between Earth’s subsurface ecosystem and the possibility of life on Mars. Ruff suggested that rocky ecosystems beneath the surface of Mars may be similar to those on Earth, offering a model for exploring past or surviving Martian life.
Similar methodology enhances data comparison
The study succeeded by employing consistent DNA sequencing protocols across more than 1,000 samples from 50 ecosystems. Co-first author Isabella Hrabe de Angelis from the Max Planck Institute for Chemistry contributed significant bioinformatics expertise to the research. Ruff attributed the success of the study to this uniform approach, which enabled unprecedented cross-environment comparisons.
