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Rock Tasting at Biosphere 2

The views expressed are those of the author and are not necessarily those of Scientific American.


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Dragos Zaharescu, Ph.D. tastes ground rock used in his plant medium

Dragos Zaharescu, Ph.D. tastes ground rock used in his plant medium

With a mischievous grin and gleaming dark eyes, Dr. Dragos Zaharescu raises a small spatula to his lips and tastes. At his feet are four containers, each filled with a different type of ground rock—granite, basalt, rhyolite or schist. Zaharescu will blend this rock with bacteria or fungus, creating a sandy medium for seedlings he grows here under the glass dome of Biosphere 2.

The dark-haired scientist cleanses his palate with water and tastes another sample. He won’t tell us his opinion yet, but dares us to participate as he serves sand like a sommelier.

“Which one do you want first?” he says.

After we sample the ground rock, Zaharescu agrees that granite tastes like salt.

Biosphere 2, where he does his research, is about 35 miles north of Tucson, Ariz. The dome of Biosphere 2 rises from the mesquite savannah like a cathedral for the celebration of science. Assorted biospherians and scientists have studied within this glass vivarium. The enthusiasm for discovery has not waned since the original crew of biospherians lived here two decades ago. Their mission: To survive for two years sustained only by the food they grew beneath the dome.

The Birth of the Biosphere Concept

Biosphere 2

Biosphere 2

The word “biosphere,” meaning the place on Earth’s surface where life dwells, was coined in 1875 by Edward Seuss, an early ecologist. New life was breathed into the biosphere concept in the 1960s, a fertile era for the melding of ecological principles and New Age philosophy. It was in this rarified atmosphere that the idea for Biosphere 2 was born.

In the early 1980s a team of scientists, architects, adventurers and dreamers decided to build an artificial biosphere—a geodesic-like structure within which they would create a self-sustaining community. Ground was broken for Biosphere 2 in January 1987, and four years later the infrastructure was complete. During construction, in a mysterious process more akin to a vision quest than the vetting of a team of scientists, eight individuals were chosen to inhabit Biosphere 2 for two years. The biospherians survived the experience, living almost entirely without assistance from the outside world. In the process, they learned as much about human relations as anything else.

Biospherian for the 21st Century

Dragos and rockubators

Dragos Zaharescu explains his research at the Biosphere 2 near Oracle, Ariz. on Oct 5, 2012. Zaharescu is a postdoctoral researcher studying how plants grow in a rocky environment.

Dragos Zaharescu is an intellectual descendant of the original biospherians. He says, without hesitation, that he would go back in time and join them in their grand experiment—if he could. Zaharescu came to Biosphere 2 as a research associate in 2011 after graduating from Vigo University in Galicia, Spain, where he investigated the interface between high-altitude organisms and their environment.

Here at Biosphere 2, Zaharescu sprouts seeds in ground rock, studying the interaction among the organisms living in his unique growth medium. He hopes his research will demonstrate how plants, microbes and fungi contribute to biological weathering, part of the process that changes rock into a living ecosystem and, ultimately, soil.

Some of the rocks that Zaharescu uses come from Arizona or New Mexico. Other rocks are sent to him by mountaineers and explorers affiliated with Adventurers and Scientists for Conservation (ASC). This organization pairs adventure athletes with scientists who need help collecting samples or data from extreme environments. Mountaineers associated with ASC collect bedrock for Zaharescu from the tops of mountain ranges.

Dragos Zaharescu shows a Biosphere 2 greenhouse to Sean Fleming, one of Carols Schwalbe's science journalism students at the University of Arizona, Tucson, Ariz.

Dragos Zaharescu shows a Biosphere 2 greenhouse to Sean Fleming, one of Carol Schwalbe's science journalism students at the University of Arizona, Tucson, Ariz.

The arrival of a new rock in the mail renews his excitement. “I open the package, and it might be a rock from Kilimanjaro. Whoa! Kilimanjaro.”

He feels a close bond with these citizen scientists, who risk life and limb to collect samples for him. “Anything can happen to them. They can die.”

Zaharescu plans to bring his team of mountaineers to Biosphere 2 for a conference once his research is complete, perhaps within the next five years. “They will be co-authors on the papers,” he says. This is the highest honor a scientist can confer on a colleague.

Life in a Bottle

Dragos Zaharescu inspects his ponderosa pine seedlings on Oct. 5, 2012 at the Biosphere 2 35 miles north of Tucson, Ariz.

Dragos Zaharescu inspects his ponderosa pine seedlings on Oct. 5, 2012 at the Biosphere 2, 35 miles north of Tucson, Ariz.

Zaharescu’s work harkens back to the studies of Dr. Clair Folsome of the University of Hawaii—a “historic figure in the Biosphere lineage,” according to Jane Poynter, one of the original biospherians. In her book The Human Experiment: Two Years and Twenty Minutes Inside Biosphere 2, Poynter describes Folsome’s life-in-a-bottle experiments. In 1968 Folsome sealed an amalgam of beach sand, bacteria and algae into flasks, sealed the flasks and sterilized them. “[N]o matter what he did to the flasks, unless he heated them to the point that the proteins broke down irreparably, or deprived the systems of light for a long time, life always persisted inside,” Poynter wrote.

Decades later, Zaharescu carries out his own “life-in-a-bottle” project. In his exquisitely designed and executed experiments, he grows grass and ponderosa pine seedlings within specially designed chambers, using rock that he or his collaborators collected and his young associates ground into a sandy mixture.

Dragos Zaharescu grows ponderosa pine seedlings on a ground-rock medium to study the impact bioweathering has on the generation of soil. Zaharescu conducts his experiments at the Biosphere 2 in 35 miles north of Tucson, Ariz. Photo taken on Oct. 5, 2012.

Dragos Zaharescu grows ponderosa pine seedlings on a ground-rock medium to study the impact bioweathering has on the generation of soil. Zaharescu conducts his experiments at the Biosphere 2, 35 miles north of Tucson, Ariz. Photo taken on Oct. 5, 2012.

Zaharescu smiles ruefully as he describes how he burned through at least 20 assistants during the rock-crushing phase of the project. To avoid contamination, any living matter had to be ground off the rock with a drill. Then the rock was crushed and sterilized in an autoclave. Each grain of sand had to be the same size, so the growth medium would be uniform.

Zaharescu didn’t spare himself the hard labor, but he wouldn’t demonstrate the process for us. “Don’t ask me to crush rock again,” he says.

“No more,” echoes Andrew Toriello, one of the few student assistants still with the project.

Toriello, a nutritional science undergraduate at the University of Arizona, joined the project in March 2012. Toriello helped denude and grind rock for months.

In spite of these monotonous tasks, Toriello enjoys working with Zaharescu. “It makes me want to stay in the science field just to know that there are a lot of people [in science] that are personable and social.”

Dragos Zaharescu explains his system for growing ponderosa pine seedlings in a ground rock medium on Oct. 5, 2012

Dragos Zaharescu explains his system for growing ponderosa pine seedlings in a ground rock medium on Oct. 5, 2012

Jennifer Presler, also a University of Arizona undergraduate, started on the project as a summer National Science Foundation intern and was hired on when her internship ended. “I wasn’t in charge of the grinding,” she says. “I was in charge of the cleaning, thank goodness.”

Presler also helped to assemble a watering system for the seedlings. “It’s a lot of fun,” she says. “His [Zaharescu’s] excitement makes me excited, too.”

After mastering rock grinding and cleaning, Zaharescu designed and built “rockubators”—hexagonal Plexiglas incubators where seedlings grow in the ground rock medium. These cradles for infant plants are kept as clean as possible during each experiment. Rows of tubes carry water to the seedlings. Gloves dangle from portholes opening into the rockubators. If plants must be handled or tubes adjusted, only gloved hands will enter the clean environment.

Dragos with his soil

Dragos with his soil

To the sandy medium, Zaharescu adds a rich mixture of bacteria and fungus that will jumpstart his plants. As water drains through the Plexiglas columns containing the seedlings, he will collect the runoff and analyze it for nutrients, bacteria, fungi and the chemical metabolites of plant growth. In this way he hopes to learn how plants, bacteria and fungi transform a rocky environment into a living ecosystem. This knowledge will help us understand how the Earth evolved from a rocky, uninhabitable planet into the green, fertile biosphere it is today.

With his experiments, Zaharescu has shown himself to be a consummate scientist with a creative approach worthy of the original biospherians. As he says, “Don’t think outside of the box. Just get rid of the box.”

Susan Swanberg About the Author: Susan Swanberg is a freelance journalist and photographer from Tucson, Ariz., and a lifelong learner. Not content with a J.D. from the University of Oregon, an M.S. in biological science from California State University Sacramento and a Ph.D. in genetics from the University of California, Davis, she is now completing an M.S. in journalism at the University of Arizona. Swanberg lives at the foot of the Santa Catalina Mountains, a picturesque mountain range surrounding Tucson. "As I explore the world of science writing," she says, "I always keep in mind the words of geneticist William Bateson: 'Treasure your exceptions.’” Follow on Twitter @seswanberg.

The views expressed are those of the author and are not necessarily those of Scientific American.






Comments 4 Comments

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  1. 1. Postman1 1:41 pm 12/12/2012

    I would love to see this type experiment done using Mars rocks. Even more reason for a sample return mission. I imagine ponderosa pine seedlings growing in a large domed crater, close to the ice caps. Ad Astra!

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  2. 2. zdragos 12:12 am 12/13/2012

    Nice idea Postman1. That would be for oxygen production. I would also love to have grasshoppers grow on grass in those rock chambers. Then used them as protein source in the places you talk about.

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  3. 3. DaniEder 12:04 pm 12/14/2012

    @Postman1 – The popular ideas of domes on Mars are mechanically naive. Assuming you have Earth-normal pressure inside, and Mars-normal pressure outside, the difference tends to blow out the dome glass or bodily lift the dome off the ground. To counteract this, you need either a very thick or massive dome structure, very strong foundations to hold it down, or piling lots of rocks on top.

    The pressure difference is 100 kPa, which at Mars gravity requires 26 tons per square meter of mass or structural strength (or a combination) to resist. This can be done, but it will not result in lightweight bubble domes like you often see in illustrations.

    Link to this
  4. 4. Postman1 9:30 pm 12/15/2012

    DaniEder Yes, I expect the first settlements will be in sealed up caves or lava tubes. Maybe, after some terraforming, or with stronger materials produced on site, those seedlings will grow there someday.

    Link to this

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