New Miscellany: new extremophiles (General)

by David Turell , Sunday, February 02, 2025, 19:39 (32 days ago) @ dhw

Deep under the surface surprisingly diverse::

https://www.sciencealert.com/earths-underworld-is-full-of-life-and-it-goes-deeper-than-...

"In an ambitious 8-year census, an international team of scientists has found an astonishing diversity of microbes living beneath our planet's surface, deeper than anything we've discovered prior.

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"'...the study has turned up lifeforms as deep as 491 meters (1610 feet) below the ocean floor, and even further below land: up to 4,375 meters (2.7 miles) deep.

"The team analyzed samples from more than 50 locations across the globe, collected from above and below Earth's surface, as well as sites like caves and deep-sea hydrothermal vents that form the surface threshold.

"Surface samples were collected from soils, sediments, or water columns, while subsurface samples were retrieved from boreholes, mines, aquifers, or the fluid from fracking.

"The diversity of life forms discovered follow an unexpected pattern.

"It's commonly assumed that the deeper you go below the Earth's surface, the less energy is available, and the lower is the number of cells that can survive," Ruff says.

"'But we show that in some subsurface environments, the diversity can easily rival, if not exceed, diversity at the surface."

"This was particularly true for microbes in marine environments, and for microbes from the taxonomic category known as the archaea domain, which became more genetically rich, with diversity more evenly spread, the deeper researchers looked. Bacterial diversity in the marine subsurface was unexpectedly high compared to surface ecosystems.

"Life in these underworlds runs on a very different timeline to Earth's bustling surface. With no sunlight, energy is sparse and must be harvested from the surrounding materials and their chemical reactions: hydrogen, methane, sulfur, serpentinization, the dead (or living) bodies of neighboring microbes, and even radioactivity.

"These ecosystems move at a tectonic pace. Scientists estimate that some cells in the deep biosphere divide only once every thousand years."

Comment: another study that demonstrates the tenacity of life. It is ecosystems all the way down. In a universe fine-tuned for life, the outcome is not surprising.