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Penelope Boston: Lessons from Life in a Cave

Penelope Boston digs deep for answers to life’s persistent questions.

Photo of Dr. Penelope Boston

Dr. Penelope Boston

What do you eat if you’re completely encased in rock? Is it possible to grow crops without sunlight? If there is life on Mars, how would we recognize it?

Questions like these have lured Penelope Boston, Ph.D., into some of the most extreme environments on Earth—those found in underground caves. The unusual organisms she finds there can inspire new approaches to energy, medicine and the search for extraterrestrial life.

All in a Day’s Work

When she gets dressed for work, Boston might wear anything from jeans and a T-shirt to a 30-pound space suit. She has descended into caverns hundreds of feet beneath the surface to endure bone-chilling cold and scorching heat. She has dived into hot acid waters and been the first human to set foot in pristine caverns.

Once, Boston strapped on an ice-filled backpack to survive a visit to Mexico’s hellish Cave of Crystals, where gas leaking up from deep magma chambers heats the air to 118°F with over 80 percent humidity.

She does all this in pursuit of “extremophiles”— organisms that thrive where most others would perish.

When Life Hands You Lemons…


'Snotties' -- actually strings of bacteria -- are one of the amazing life forms Boston has found in caves.

The organisms Boston studies often live in absolute darkness. They are buried in caves deep in the Earth’s crust, encased in what are essentially alien worlds on our own planet. These environments can be highly acidic, and though they may be replete with minerals like sulfur, manganese and iron, caves often lack the basic nutrients that support most food webs above ground.

Despite these unfriendly surroundings, life thrives in the fissures and caverns of the world below. Boston’s research has illuminated an incredible array of bacteria, viruses, fungi and archaea adapted to survive each cave’s unique set of conditions.

Boston and her colleagues use Scanning Electron Microscopy and Electron Dispersive Spectroscopy analysis to study these cave-dwelling organisms and their energy sources. They’ve found creatures that essentially eat rocks by using biochemical processes to extract energy from minerals in the cave walls. Other organisms thrive in acidic pools of water or near gas vents; some subsist on those organisms or on the occasional bits of organic matter that fall in through cave openings.

Mighty Microbes Offer Inspiration

Studying cave-dwelling microbes can inspire innovative ways for humans to address our own energy needs. “Energy is something that biology has been doing very successfully for many billions of years,” said Boston. Learning from the chemical and biological processes these organisms use could potentially help us tap into new energy sources.

The huge diversity with which organisms approach this need for energy and how to process it…is something that we can at least be inspired by.” – Penelope Boston

The viruses and bacteria Boston encounters below the surface may also offer novel antibiotics or enzymes useful for medicine and industrial applications. Studying extremophiles could also yield insights about the origins of life on Earth, or help us understand how organisms adapt to a changing climate.

Boston also believes her research offers clues about the potential for life on other planets. Could caves beneath the Martian surface support life forms similar to the extremophiles in caves here on Earth?

Audio interview

Penelope Boston is Director of Cave and Karst Studies at the New Mexico Institute of Mining and Technology (New Mexico Tech). Spanning the frontiers of biology, chemistry and geosciences, her research demonstrates that working across disciplines makes for science that is more than the sum of its parts.