I sat down with Ben Casterline a few hours before his internship at the National Museum of Natural History came to an end. He had been studying “paleoclimatology” while working with Smithsonian paleontologist Scott Wing. A fourth-year student at the University of Chicago majoring in biology and paleontology, Ben spent four weeks with Wing in Wyoming’s Bighorn Basin, quarrying for leaf fossils, digging trenches to measure stratification, and prospecting for new dig sites. In the Bighorn, rocks exposed at the surface represent a period of global warming known as the Paleocene Eocene Thermal Maximum, or PETM. (See "Going Behind the Scenes with Smithsonian Researchers."). In our interview, Ben remembered his time camped out with scientists and other interns (and, at one point, with Smithsonian Secretary, G. Wayne Clough) as “intellectually stimulating.”
On Working with Fossils
“It’s really about looking at the evidence of climate change, and we are trying to expose that!” Ben exclaimed when discussing his work back in Washington, D.C., after the Wyoming trip. He used an “air scribe,” a tool similar to a miniature jackhammer, to knock off rock from fossilized leaves, Ben assisted Wing through the process of revealing the visible history of climate change as witnessed through changing patterns in the morphology of those leaves. Ben’s other work included photographing the fossils and arranging specimens into groups of similar characteristics, known as “morphotypes.”
“It’s really about looking at the evidence of climate change, and we are trying to expose that!” Ben exclaimed when discussing his work back in Washington, D.C., after the Wyoming trip. He used an “air scribe,” a tool similar to a miniature jackhammer, to knock off rock from fossilized leaves, Ben assisted Wing through the process of revealing the visible history of climate change as witnessed through changing patterns in the morphology of those leaves. Ben’s other work included photographing the fossils and arranging specimens into groups of similar characteristics, known as “morphotypes.”
On Climate Change
“Models are more reliable the more data you give them,” Ben said as we discussed how his work relates to climate change, “Fossils allow us access to a record stretching back millions of years.” He explained that the study of fossil leaves allows us to see how plant communities have reacted to climate change in the past. The geographic distribution of plants is highly linked to climate: when temperatures increase, for example, plants from the south tend to replace less heat-tolerant natives. The movement reverses when temperatures cool down again.
Before and after the PETM, plants in the Bighorn Basin were similar to those in the modern southeastern United States: laurels, plane trees, etc. During the period of warming in between, plants were similar to those in subtropical Mexico: palms, a lot of legumes, etc. Ben suggested that this is why work in this field is so important; it provides us with clues to our own future.
“Scientists are able to create models that can be accurate!” he says. “What can you do with people but show them evidence?”
Ben Casterline is a fourth year student at the University of Chicago majoring in biology and paleontology. He is a former intern at the National Museum of Natural History.
Jarrid Green is a former Smithsonian intern and recent college graduate from the University of Maryland.
