PNNL

PNNL scientists are getting the dirt on soil and what it says about our planet’s health

The foliage this time of year beckons us outside, perhaps for a stroll along the Columbia River or an early-morning hike up Badger Mountain.

The next time you take a step outdoors, consider for a moment the life beneath your feet. Just one handful of soil includes more than 100 billion microorganisms — about the same number as stars in our galaxy.

Soil studies are serious science at the Department of Energy’s Pacific Northwest National Laboratory.

Much more important to our world than the word “dirt” implies, soil is central to energy, national security and our climate.

Soil filters our water and regulates our atmosphere, serving as a life support system for the planet. The microbes that call soil home also are crucial to food production the world over.

It is this significance that motivates PNNL researchers to tease out soil’s secrets. We have come a long way toward understanding exactly what resides in the soil — whether bacteria, viruses, fungi, archaea or other forms of life.

Now our researchers are tackling much bigger questions around this community of microbes, known as the microbiome: What are they doing? How do they interact? Answering these and other questions will enable us to grow bioenergy crops more effectively, weaning our planet from fossil fuels, as well as to understand our climate more fully.

Some of the answers will be found at the PNNL field site in Prosser managed by Washington State University. Soil conditions are monitored and factors like irrigation are controlled closely so researchers can explore several soil processes in ways impossible to do in uncontrolled conditions.

Then, the samples are brought to PNNL and analyzed in dozens of ways. How much carbon is present? How are the grains of soil shaped? Does water flow easily between minerals? Which microbes are present and what are they doing?

Most of what our soil researchers study is unimaginably small.

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Soil samples from the Mid-Columbia region, the Midwest, Alaska and other sites around the world are collected by PNNL scientists, then brought back for study at the laboratory. Courtesy of Andrea Starr/PNNL Andrea Starr | Pacific Northwest

Consider the case of a pocket of carbon molecules locked between two fragments of calcium, each a fraction of the width of a human hair. What will happen to that carbon? Will it catch a ride on a passing trickle of water and enter a nearby river, affecting water quality?

Will it work its way between the fragments, up through the soil and into the atmosphere? Or will it stay put, stored for years or decades?

Multiply that process by billions upon billions and you begin to see the complexity in a single, small plot of land. Multiply once again, and you enter the realm of climate scientists who synthesize information about incredibly complex processes from soil, water and air to gauge our planet’s health.

These small-scale processes add up and, at the planetary scale, are central to our future.

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Microbes such as this one, shown on the root surface of the plant Arabidopsis, play a crucial role in soil. Courtesy of PNNL

They are key to understanding the chaos that erupts underfoot when conditions change suddenly: for instance, when a flood ends a prolonged period of drought.

Such extremes upend the lives of the microorganisms that live in that soil, changing how water flows, how plants grow and how events like a rapid storm surge are weathered.

Issues like these embody the type of big challenges that a national laboratory such as PNNL is uniquely capable of addressing.

Unique resources, including the Plant Sciences Laboratory at the Environmental Molecular Sciences Laboratory at PNNL, allow scientists to control conditions, such as temperature and moisture, to an exceptional degree, offering ways to address some of science’s toughest questions.

It’s remarkable to me, as a resident of the Tri-Cities, that the findings of PNNL scientists about soil samples from our very own region inform the knowledge of soil around the globe and the understanding of the health of our planet.

That’s something to think about the next time you set foot outside.

Steven Ashby is director of Pacific Northwest National Laboratory in Richland.
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