Exploring life below the background at SNOLAB

From sunburn to skin cancer, the risks of too much radiation are fairly well known. But what about the opposite? What happens when there’s too little radiation?

That’s the radical question a team of researchers from NOSM University (formerly the Northern Ontario School of Medicine) is exploring through a project supported by NII Environment, Bruce Power, and NSERC.

The work takes place two kilometres underground in SNOLAB, the deepest clean laboratory in the world, located in Sudbury, Ontario. There, shielded from most natural sources of ionizing radiation, scientists are studying how living organisms respond when background radiation is almost entirely eliminated.

Panoramic view of the life sciences laboratory in SNOLAB.

What happens without radiation?

Life on Earth evolved in an environment that includes low levels of ionizing radiation, including from cosmic rays, radioactive rocks, and even naturally occurring isotopes within our own bodies. To this day, every organism on the planet lives with a constant background dose. This project asks whether some level of background radiation is not only harmless but possibly even necessary for healthy cellular function.

If removing radiation disrupts biological processes, it could reshape how we think about long-term space travel, radiation safety and even the fundamentals of cell biology.

A tiny test subject with big insights

In 2024, the team made significant progress using yeast (Saccharomyces cerevisiae) as a test organism. Yeast is simple, well-studied, and ideal for genetic experiments, making it a powerful model for early-stage research.

The NOSM University SNOLAB research team.

One set of experiments tested whether dried-out (desiccated) yeast could act as a biological radiation detector. If so, it could be a solution to one of most prominent challenges in long-term biosensing experiments: shelf-life and stability.

Previous studies have shown that when yeast is dried, its metabolism slows dramatically, essentially “pausing” the cells. This makes it easier to measure accumulated damage over time from stressors like radiation. Remarkably, desiccated yeast can endure for centuries—or even millennia. Viable yeast cells have been recovered from Philistine beer jugs that are thousands of years old. After rehydration, they sprang back to life, fermenting just like modern brewers’ yeast.

Researchers exposed different yeast strains to neutrons, protons, and x-rays and tracked the survival rates. Dried yeast was unexpectedly tough, showing a threefold increase in radiation resistance compared to hydrated yeast.

Saccharomyces cerevisiae, also known as brewer's yeast or baker's yeast (Credit: Mogana Das Murtey and Patchamuthu Ramasamy, Wikipedia)

The relative biological effectiveness (RBE, a measure of how damaging types of radiation are to living tissue) of neutrons and protons in dried yeast closely matched the results seen in hydrated cells. What’s more, the presence or absence of oxygen had no measurable effect on how the dried yeast responded to radiation—a result that will simplify future experiments.

The findings suggest that dried yeast could be a reliable long-term biological dosimeter (equipment that measures radiation exposure) for tracking radiation exposure in environments like SNOLAB, or potentially even in space.

Slower growth, deeper questions

In another experiment, yeast was grown inside SNOLAB for more than 100 generations (approximately one week). The results were surprising: underground yeast grew up to 16% more slowly than surface-level control strains.

Lead containment shielding in SNOLAB used to reduce background gamma radiation to desiccated yeast samples.

This suggests that natural background radiation may play a role in regulating growth and metabolism. To investigate why, the team is analyzing gene expression data to see which cellular processes are affected by radiation deprivation.

Next, they’ll study yeast that’s been depleted of potassium-40, a naturally radioactive isotope found in all life. Removing this internal radiation source may help isolate the pure effects of an ultra-low-radiation environment.

From yeast to human cells

Building on the yeast research, the team is now examining how low-radiation environments affect cancer risk and cellular metabolism for human bronchial epithelial cells (a standard model in lung cancer research). Early studies will also explore how these cells handle oxidative stress, a key factor in aging and disease.

What began with yeast may ultimately reshape our understanding of how radiation shapes life. The findings from this work have the potential to inform medical research, improve long-duration space travel, and challenge assumptions about radiation safety.

At the Nuclear Innovation Institute and funded by Bruce Power, the Environment program within the Bruce Power Nexus Research Centre is committed to research on environmental and human health. Read the 2025 Environment Annual Report to learn more about the other research projects happening through this program.

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Dr. Stephanie Keating is Director, Environment, part of the Bruce Power Nexus Research Centre.