In subduction zones—where the planet’s most powerful earthquakes occur—tectonic activity may act like a natural “pump,” transporting microorganisms buried deep beneath the seafloor back toward the surface. This is the conclusion of research presented at the SSA Annual Meeting 2026.

These microorganisms are thought to be among the most resilient “sleeping beauties” on Earth, remaining dormant for thousands or even millions of years beneath sediment layers up to a kilometer thick. Their survival is made possible by specialized biological adaptations.

However, to pass these adaptations on to future generations, the microbes must eventually return to the upper layers of the seafloor, where they can feed, grow, and reproduce.

This is where the so-called tectonic pump comes in, as explained by Zhengze Li, a doctoral candidate at the University of Southern California. Li and his colleagues argue that fault movements in subduction zones generate fluid flows that carry buried microorganisms upward.

According to their models, this tectonic pump may circulate more than one million gigatons of fluid per million years, transporting up to 10³⁰ microbial cells. In his presentation, Li described how this microbial “elevator” works.

In subduction zones—where one tectonic plate sinks beneath another—sediments from the descending plate are scraped off and accumulate into a wedge. Some microorganisms continue descending toward the mantle, a path researchers refer to as a “journey to hell.”

Others, however, avoid this fate. They can move upward through cracks and faults under the influence of tectonic slip. When they reach the shallower layers of the seafloor, “they can reactivate and reproduce,” Li noted. The full cycle may take tens of millions of years. So-called cold seeps on the ocean floor, where fluids escape from subsurface layers, provide direct evidence of this tectonic circulation. These sites allow scientists to collect microbial samples and study the relationship between tectonic processes and life beneath the seabed.

“We can also examine how seismic activity relates to the abundance of different microbial groups, and we find a positive correlation between seismic energy and the presence of subsurface microorganisms,” Li said.

Field research at the Costa Rica subduction zone showed that higher seismic energy levels are linked to greater abundance of microbes typically found in deep underground environments. Li added that the tectonic pump is not limited to major earthquakes. Even “quiet” phenomena, such as slow slip events or seismic creep, can drive the movement of fluids and microorganisms.

Co-author Karen Lloyd, a microbial biogeochemist at USC, has identified mechanisms that allow deeply buried microorganisms to survive for vast periods, including DNA repair processes and enzymes that break down organic matter at depth.

Genomic studies indicate that mutations in these organisms are often conservative, preserving key traits for millions of years. But to pass on these traits and continue evolving, the microbes must wait for the tectonic “elevator” to carry them back to a more hospitable environment.