Surficial sediment communities were different from each other and from the deep subsurface samples.

Therefore, deep subsurface environments that combine these stressors, potentially including the subsurface of Mars, may be more habitable than previously thought.

Studies on the microbial communities of deep subsurface sediments have indicated the presence of Bacteria and Archaea throughout the sediment column.

In addition, there are indications of microbes intimately attached to sediment particles that are believed to have come from the deep subsurface.

It remains unclear how geofluids influence the composition of the seabed microbiome and if they transport deep subsurface life up to the surface.

ASTEROIDS "We think of the deep subsurface as extreme but it's really quite protected - from asteroids or from volcanic eruptions," he said.

Our findings provide new insights into the carbon cycle in the deep subsurface and suggest the redistribution of lipids into putative symbionts within this community.

Deep subsurface environments can harbour high concentrations of dissolved ions, yet we know little about how this shapes the conditions for life.