Worlds Beneath Our Feet: Andrew Knoll ’73 and Daniel Richter ’73 Explore Life’s Origins Underground

Andrew Knoll ’73 was on top of the world, literally, when he began collecting rocks that would begin pinning down dates for the development of life on Earth. He and colleagues cruised in a 30-foot boat around the remote island of Spitsbergen, halfway between Norway and the North Pole, sampling from ancient reefs of fossilized microorganisms created over 600 million years ago.

“It turns out that we live on a planet that records its own history,” Knoll says, “and that history is largely found in sedimentary rocks laid down one bed atop another over time.”

Since that time four decades ago, Knoll has become one of the foremost geoscientists to establish that history, deducing the environmental factors that have led to booms and busts of species over a timeline of more than 3 billion years.

Now Fisher Research Professor of Natural History at Harvard University, he isn’t the only Lehigh alum who has explored the secrets hidden beneath our feet—or even the only Lehigh alum from his graduation year. His classmate Daniel Richter ’73, Theodore S. Coile Distinguished Professor in the Nicholas School of the Environment at Duke University, has examined soils and sediments of more recent origins to show how humans have impacted the planet.

Together, their work stretches from the beginning of life on Earth to the present moment, using tools of geoscience to show how that history still impacts us today.

Finding Life In Rocks

Growing up near Reading, Pennsylvania, Andrew Knoll collected fossils and read books on archaeology as a boy, learning “there is all sorts of interesting history beneath our feet, if you just know where to look for it.”

Among other accolades, Knoll received the 2022 Crafoord Prize in Geosciences, a complement to the Nobel Prize, for the “fundamental contributions to our understanding of the first 3 billion years of life on Earth and life’s interactions with the physical environment through time.”

His work not only sheds light on ancient mysteries, but also offers insights into our own era, when carbon is once again building in our atmosphere due to man-made pollution.

“What we see at the end of the Permian period is really a distant mirror on the 21st century,” says Knoll, who contributed to a recent U.N. global report on climate change. Over the years, he’s also worked to educate the public with appearances on the PBS science program “NOVA,” and the book “A Brief History of Earth,” a synopsis of how the Earth has changed over 4 billion years.

“Many geologists think hard about how knowing something about the past may help us understand the future,” he says. “I want to try and help the public understand the changes we are seeing, and how investing in solutions now will be far better in the long run than doing nothing.”

Humans’ Impact on the Land

Daniel Richter investigates the way that the Earth is being changed by human activity in a more immediate way, looking at the soil beneath our feet. He still remembers the sweltering hot day as a graduate student at Mississippi State, when a soil professor led a field trip into a nearby forest, pulling up pine needles from the ground.

“He got a big handful of soil and started talking in the most poetic way,” he remembers, “saying if you understood soil, you could understand so many other areas.” Richter was hooked, beginning a scientific career to examine the dirt and clay we take for granted.

“Ninety-nine percent of the terrestrial surface has some kind of soil on it,” Richter says. And yet, as Leonardo DaVinci said 500 years ago, we still “know more about the movement of celestial bodies than about the soil underfoot.”

Richter takes a multidisciplinary approach, impacted by his time at Lehigh, where he focused his time on playing soccer and pursuing a major in philosophy—a subject not unlike soil science in a way.

“You look around and see all of this superficial stuff, but what’s controlling things is the invisible stuff beneath the surface,” he says.

He continued his education after college, working a year at Bethlehem Steel and hiking the Appalachian Trail before following his girlfriend, now wife, Susan (Adam) Richter ’75 to Mississippi State, where he enrolled in forestry.

He went on to earn his Ph.D. in soil science and ecology at Duke. After graduating, he worked at Oak Ridge National Laboratory, where he participated in debates among scientists over the impact of acid rain on soil and water. He became fascinated by how humans impact the land.

“Until recently,” he says, soil science textbooks “might have had one or two references to human beings.” And yet, “like it or not, more than half of the soils on Earth are being managed or altered by humanity,” he says.

At Duke, he inherited a long-term soil experiment that examines how a pine forest has restored soil after 150 years of cotton farming. In his book “Understanding Soil Change,” Richter has shown how soil carbon, nitrogen, phosphorus and a dozen other chemical elements change in soil over time, affecting soil far more deeply than previously understood. Like Knoll, Richter has often used isotopes to estimate how the Earth cycles its chemical elements.

Starting in 2005, he began examining other long-term soil experiments (LTSEs) around the world, compiling them into a database of more than 200 studies. Along with colleagues, he has shown how the explosion in agricultural production brought on by improvements in fertilizer and other practices has had unintended consequences in soil erosion, runoff and overfertilization, affecting the environment and public health.

More recently, he’s begun looking at city soils, using new instruments that can detect potential contaminants within seconds. After the catastrophic wildfires in Los Angeles in January, he has analyzed more than 300 soil samples provided by citizens, showing potentially dangerous amounts of lead and other contaminant metals.

Richter has become so passionate about tracing humankind’s impact on the Earth that he joined the Anthropocene Working Group, a collection of geological scientists who, after 10 years of study, proposed to rename our current geological epoch from the Holocene to the Anthropocene given the scale at which humans are changing the land, ocean and atmosphere.

While the scientific community has been resistant to the proposal so far, he is optimistic that it will gain traction over time and help bring new attention to the Earth sciences to better learn how we are changing our planet for better or worse.

“Prior to this, geologists have always looked back through time, but we are trying to come to grips with the human role in the present,” Richter says. “This question is as much geological as it is philosophical.”

Story by Michael Blanding