Earthquakes have the potential to reshape this environment in several ways. Shaking can break open new rock surfaces, force out fluids that were previously sealed away, and redirect the flow of water through the subsurface. Each of these effects can create fresh chemical reactions, which in turn alter the types of energy available to microbial communities. The authors refer to this shift in available resources as a change in the chemical “menu” that microbes can draw from.

Sampling Yellowstone’s Deep Fluids After the Quake Swarm

To understand how seismic activity influenced this hidden ecosystem, the researchers collected water samples from a nearly 100-meter deep borehole located along the western edge of Yellowstone Lake. They sampled the site five times throughout 2021, giving them a rare look at how conditions changed both immediately and over the following months.

Analyses of these samples showed notable increases in hydrogen, sulfide, and dissolved organic carbon after the earthquakes. These compounds serve as important energy sources for many subsurface organisms. As the chemistry of the water shifted, the team also detected a rise in planktonic cells, suggesting that more microbes were present in the water column than before. This combination of chemical and biological changes indicates that the quake swarm temporarily boosted the resources available to deep microbial life.

Microbial Communities in Motion

Beyond detecting an increase in cell numbers, Boyd and colleagues observed that the types of microbes present changed over time. This result stands out because subsurface microbial communities in continental bedrock aquifers are often considered relatively stable. In contrast, the Yellowstone system appeared to respond quickly and noticeably to the pulse of seismic energy.

According to the authors, the kinetic energy associated with earthquakes can influence both the chemistry and the biological makeup of aquifer fluids. Their findings imply that even small seismic events can drive meaningful ecological shifts underground.

Implications for Other Worlds With Rock and Water

The processes observed in the Yellowstone borehole may not be unique. Many regions around the world experience regular seismic activity that could similarly reshape subsurface energy supplies. If this mechanism is widespread, it could help explain how microbial life persists in deep and isolated environments.

The team also notes that the same basic dynamics might occur on other rocky planets that contain water. If earthquakes or similar geological motions can refresh chemical resources below the surface, this could expand the possible habitats for microbes on worlds such as Mars.

Aerosols are tiny droplets or solid particles suspended in the air, and they surround us constantly. Some are large enough to see, such as springtime pollen, while others, like viruses that circulate during flu season, are far too small for the human eye. A few can even be sensed by taste, including the fine salt particles carried on ocean winds.

PhD student Andrea Stöllner, a member of the Waitukaitis and Muller groups at ISTA, studies the behavior of ice crystals that form within clouds. To better understand how these crystals gather charge, she works with model aerosols made from very small, transparent silica spheres.

Together with former ISTA postdoc Isaac Lenton, ISTA Assistant Professor Scott Waitukaitis and collaborators, Stöllner has created a technique that uses two intersecting laser beams to trap, stabilize, and electrically charge a single silica particle. This setup opens the door to new investigations into how cloud electrification begins and how lightning is sparked.

Building a Stable Laser Trap

Andrea Stöllner works at a large laboratory table filled with polished metal components. Green laser beams cross the space, bouncing from mirror to mirror. A slow, steady hissing noise comes from the table, similar to air leaking from a tire. “It’s an anti-vibration table,” Stöllner says, pointing out how it protects the lasers from small disturbances in the room or from nearby equipment, which is essential for extremely precise measurements.

The beams travel through a series of aligned parts before converging into two narrow streams that enter a sealed container. Where they meet, they create a concentrated point of light that can hold small particles in place. These “optical tweezers” keep drifting aerosols suspended long enough to study them. When a particle is caught, a bright green flash appears, confirming that the trap has successfully grabbed a glowing, perfectly round aerosol particle.

“The first time I caught a particle, I was over the moon,” Stöllner recalls of her breakthrough moment two years earlier, just before Christmas. “Scott Waitukaitis and my colleagues rushed into the lab and took a short glimpse at the captured aerosol particle. It lasted exactly three minutes, then the particle was gone. Now we can hold it in that position for weeks.”

Achieving this level of control took nearly four years. The experiment began with an earlier version developed by Lenton. “Originally, our setup was built to just hold a single particle, analyze its charge, and figure out how humidity changes its charges,” Stöllner says. “But we never came this far. We found out that the laser we are using is itself charging our aerosol particles.”

How Lasers Knock Electrons Loose

Stöllner and her colleagues discovered that the particles gain charge through a “two-photon process.”

Aerosol particles usually carry almost no net charge, with electrons (negatively charged entities) orbiting within each atom. Laser beams are made of photons (particles of light traveling at the speed of light). When two photons strike the particle at the same moment and are absorbed together, they can remove a single electron. Losing that electron gives the particle one unit of positive charge, and with continued exposure, the particle becomes progressively more positively charged.

For Stöllner, identifying this process has opened new opportunities. “We can now precisely observe the evolution of one aerosol particle as it charges up from neutral to highly charged and adjust the laser power to control the rate.”

As the charge builds, the particle also begins to lose charge again in sudden, short bursts. These spontaneous discharges hint at behaviors that may occur naturally in the atmosphere.

High above, cloud particles may undergo similar cycles of charge buildup and release.

Searching for Lightning’s First Spark

Thunderstorm clouds contain a mix of ice crystals and larger chunks of ice. As these collide, they trade electrical charges. Over time, the cloud becomes so electrically imbalanced that lightning forms. One idea is that the earliest spark of a lightning bolt could arise directly from charged ice crystals. Yet the exact mechanism behind lightning formation remains unresolved. Other theories propose that cosmic rays start the process because the charged particles they produce accelerate within existing electric fields. According to Stöllner, the current scientific view is that, in both scenarios, the electric field inside clouds appears too weak to initiate lightning on its own.

“Our new setup allows us to explore the ice crystal theory by closely examining a particle’s charging dynamics over time,” Stöllner explains. While natural ice crystals in clouds are much larger than the silica particles used in the lab, the team hopes that understanding these small-scale effects will reveal the larger processes that create lightning. “Our model ice crystals are showing discharges and maybe there’s more to that. Imagine if they eventually create super tiny lightning sparks — that would be so cool,” she adds with a smile.

“Most living organisms, including humans, cannot survive even briefly in the vacuum of space,” says lead author Tomomichi Fujita of Hokkaido University. “However, the moss spores retained their vitality after nine months of direct exposure. This provides striking evidence that the life that has evolved on Earth possesses, at the cellular level, intrinsic mechanisms to endure the conditions of space.”

Asking Whether Moss Could Survive Beyond Earth

Fujita began exploring the possibility of “space moss” while studying plant evolution. He was impressed by mosses’ ability to colonize the harshest environments on Earth. “I began to wonder: could this small yet remarkably robust plant also survive in space?”

To investigate, Fujita’s team exposed Physcomitrium patens, also known as spreading earthmoss, to a simulated space environment featuring intense UV radiation, extremely high and low temperatures, and vacuum-like conditions.

Testing Moss Structures Under Extreme Stress

The researchers compared three moss forms: protenemata (juvenile moss), brood cells (stress-induced stem cells), and sporophytes (encapsulated spores). They aimed to identify which structure had the greatest likelihood of enduring space.

“We anticipated that the combined stresses of space, including vacuum, cosmic radiation, extreme temperature fluctuations, and microgravity, would cause far greater damage than any single stress alone,” says Fujita.

Their experiments showed that UV radiation posed the biggest threat, and sporophytes clearly outperformed the other structures. Juvenile moss did not survive strong UV exposure or extreme temperatures. Brood cells fared better but still fell short. By contrast, the encased spores showed ~1,000x greater UV tolerance and remained capable of germination even after enduring −196°C for more than a week or 55°C for an entire month.

Why Encased Spores Withstand Harsh Conditions

The team concluded that each spore’s surrounding structure likely absorbs harmful UV light and provides physical and chemical shielding. They suggest that this protective feature may have helped ancient bryophytes, the plant group that includes mosses, move from water to land roughly 500 million years ago and survive repeated mass extinctions.

To determine whether this adaptation held up in real space, the researchers sent sporophytes into orbit.

Launching Moss to the ISS for a Real-World Trial

In March 2022, hundreds of sporophytes traveled to the ISS aboard the Cygnus NG-17 spacecraft. After their arrival, astronauts mounted the samples on the exterior of the station, exposing them to space for 283 days. The specimens later returned to Earth on SpaceX CRS-16 in January 2023 and were brought back to the lab for analysis.

“We expected almost zero survival, but the result was the opposite: most of the spores survived,” says Fujita. “We were genuinely astonished by the extraordinary durability of these tiny plant cells.”

Strong Survival and Healthy Return to Earth

More than 80% of the spores endured the full trip, and all but 11% of those survivors successfully germinated in the laboratory. Measurements of chlorophyll showed normal levels for nearly all pigments, except for a 20% drop in chlorophyll a, a light-sensitive compound. Despite this reduction, the spores remained healthy.

“This study demonstrates the astonishing resilience of life that originated on Earth,” says Fujita.

The team also used their data to build a mathematical model estimating how long the spores might last in similar conditions. Their calculation suggested a potential survival span of up to 5,600 days, or about 15 years, although they stressed that more data is needed for a firm conclusion.

Implications for Growing Life Beyond Earth

The researchers hope these findings support future studies on how extraterrestrial soils might sustain plant life and encourage efforts to use mosses in developing agricultural systems for off-world environments.

“Ultimately, we hope this work opens a new frontier toward constructing ecosystems in extraterrestrial environments such as the Moon and Mars,” says Fujita. “I hope that our moss research will serve as a starting point.”

This work was supported by DX scholarship Hokkaido University, JSPS KAKENHI, and the Astrobiology Center of National Institutes of Natural Sciences.