URIs_MOMENTUM_Research_and_Innovation_Magazine_Spring_2024_M

“These organisms, on average, live on so little energy that they directly challenge our understanding of what it means to be alive.”

STEVEN D’HONDT Professor Oceanography

- Steven D’Hondt

Core sediment samples.

When he earned his doctorate in geological and geophysical sciences at Princeton University, there were only four or five micropaleontologist openings in the country, including one at URI’s Graduate School of Oceanography (GSO) which D’Hondt claimed. At the University for more than 30 years, D’Hondt has led the Subsurface Biospheres team of the NASA Astrobiology Institute, and he was an executive committee member of the Center for Dark Energy Biosphere Investigations. He has published more than 100 peer-reviewed articles and been cited more than 10,000 times. D’Hondt and his hundreds of global collaborators have over the years better understood the microbial organisms that challenge our definitions of life. Yet, countless frontiers remain unexplored, including how these organisms interact with one another and how the study of these microscopic creatures apply to human life. One of D’Hondt’s current projects, in collaboration with the Rhode Island Nuclear Science Center, stems

from a concept first proposed in the 1950s that the radioactive splitting of water supports microbial life in marine sediment. This research has bolstered understanding of how to manage nuclear waste. “We may not yet know how we can extend human life from these microbes living forever,” D’Hondt says, “but we learn basic things about how to engage the world in other ways. And it’s not predictable. We don’t know what we are going to learn that is of use, but we do learn things that are of use.” D’Hondt says that his research is only possible because of his collaborators—who range from undergraduate students to fellow tenured professors—and because of opportunities like the AAAS fellowship and financial support of the University. “It is a tremendous privilege to be paid to learn things that people didn’t know before and share that with the world,” he says.

Professor Steven D’Hondt has dedicated 25 years to studying the subsurface biome of the ocean floor, working with his peers and students around the globe. The AAAS fellowship honors his work on the diversity and processes of microbiological communities within subseafloor sediments. “This is a globe-spanning biome that we know very little about,” D’Hondt says. “I’ve been fortunate to spend much of my career exploring it.” Although these organisms reside miles below 70 percent of the planet’s surface, they can survive and are rarely studied. “It’s an underexplored living world right here on our own planet,” D’Hondt says. Steven D’Hondt

beneath the ocean floor is significant on its own, and D’Hondt is fascinated by the makeup of the marine organisms. Surviving at mind-bogglingly low rates of respiration, they must either live an extraordinarily long time (perhaps millions of years) or reproduce on far less energy than previously thought possible. “These organisms,” D’Hondt says, “on average, live on so little energy that they directly challenge our understanding of what it means to be alive.” D’Hondt began his academic career at Stanford University, where he received a bachelor’s degree in geology. He then worked for the U.S. Geological Survey in California, studying ocean history by searching for evidence of ancient asteroid and comet impacts in marine sediment.

The sheer scope of so many living things so far

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