COLUMBIA – John Huntley stood on top of a cold North Carolina mountain 20 years ago, looking at the remains of organisms embedded in rock. The place where the mountain stood was once an ocean rich with life. In that moment, Huntley knew he wanted to dedicate his future to studying the past.
Hours after departing from his friend’s college field trip, Huntley dropped his classes in elementary education and began pursuing a degree in geology. He didn’t tell his parents. He didn’t tell his friends. Huntley said it was a rash decision, but he says it was the best one he ever made.
“At that point I had determined that I was going to be a geology major before even taking a class,” Huntley said. “Everything really that got my attention was finding evidence for the history of life and understanding how environments have changed over time and how organisms changed and find out why and how that process works.”
Now Huntley, 37, is an assistant professor at the University of Missouri in Columbia. He specializes in the field of paleobiology, the study of ancient forms of life through fossils. His research looks at 10,000-year-old fossils of clams and other mollusks. Turns out that these ancient shells carry a warning for modern humans. Huntley has uncovered evidence that parasitic flatworms infected these mollusks in an era when the Earth’s climate was warmer and sea levels were higher. The worms would burrow into the clam’s shell and then feed off its delicate inner tissues before moving on to another host.
To Huntley, the implication is clear: In a world warming due to climate change, modern humans could be at increased risk of infection or disease from modern-day flatworms similar to those 10,000 years ago, Huntley said.
“And of course the implication is, ‘What are we going to do?'” Huntley said. “Sea levels rising, it is getting warmer. Are we making conditions that will be conducive to big boost to the number of parasites in estuaries?”
Looking into the research
Looking under a microscope of 10,000-year-old fossils of clams and other mollusks over years from China, Italy and Germany, when the sea level in those areas were higher and the climate warmer, Huntley found an increased number of small pockets or holes inside the fossils of these organisms where he concludes the parasites lived.
Huntley said these flatworms have fairly complex life cycles, usually inhabiting two to three different organisms through the process of their lives. They start out as eggs in the water but as immature babies called larvae they will infect an intermediate host, typically an invertebrate such as a clam. The infected clam shells develop oval-shaped pits where the clam grew around the parasite to keep it out. The prevalence of the pits provide clues to how the clams adapted to defend against trematodes.
Feeding off the intermediate host’s insides gives flatworms an opportunity to mature into full adults. Once the flatworm is an adult, it will move onto vertebrate hosts, like mammals, so it can produce offspring.
“While they are in clams often time they will be eating gonads and other parts of the tissue because they are really rich in nutrients,” Huntley said. “There is definitely a negative influence on the body. But, ultimately, what they have to do is get to their definitive host that is a vertebrate. So, it could be a bird, it could be a human.”
Once inside a vertebrate host, the flatworm lives inside the digestive tract and produces eggs that come out of the host’s feces. Symptoms in humans can range from liver and gall bladder inflammation, brain inflammation, chest pain and fever.
Huntley said his team was able to confirm the correlation between sea level rise and these parasites after they traced their interaction with other organism through the fossil record in various locations, like Germany and China. The record found that as temperature increased ,from atmospheric carbon dioxide rising, and sea level rose the traces of these flatworms appeared more frequently in the fossils of these organisms. This temperature spike lasted around 3,000 years.
“If you are exposed to the water, if it touches you, if you ingest it, the little larvae worms can actually swim and bore in,” Huntley said. “It is a nasty world.”
Although Huntley feels pretty confident about where the research is heading, he admits there are a few things his team must rule out first before they can undeniably say that rise in number of the flatworms is due to rise in sea level.
For example, another possibilities his team are currently looking in to is how the temperature could affect the behavior of these flatworms. Huntley and his team have so far ruled out saltiness of the waters and number of clams as factors that could increase the number of flatworms.
The journey up to now
Huntley came to this conclusion after several months working with geologists from around the world.
He received his undergrad in geology at Appalachian State University, his masters in geology at University of North Carolina at Wilmington, and his Ph.D. in geology from Virginia Tech.
After completing his Ph.D., Huntley had difficulty getting any jobs other than short-term positions in teaching or research. Eventually, he received the Humboldt Research Award to do research in Germany through the Humboldt Foundation, named after Alexander von Humboldt. Huntley said the purpose of the foundation was to promote science, promote international exchange, and establish collaboration between scientists in Germany and elsewhere around the world.
He and his wife of one year dropped everything and left for Germany. Huntley said being newlyweds and heading to a place unfamiliar to them had its challenges.
“They sent us both to language school so we could actually communicate a little more effectively and it worked out quite well,” Huntley said “My wife wasn’t allowed to work while she was there. She didn’t have a work visa.”
Instead, Huntley and his wife decided to survive on one income. On most days, Huntley’s wife would come with him out to the field, and sometimes they traveled to other cities.
While in Germany Huntley began to study the fossils of organisms and how the environment affected them. He noticed traces of parasites in organisms in several regions of the world.
Huntley later moved to New York did research where he received an email from friend and German researcher Manja Hethke that would further his research on the prevalence of parasites in mollusks fossils several thousand years ago.
“He was a Ph.D. student in the group at the time,” Huntley said. “He said, you know I have these samples left over from my own undergraduate thesis and I think I found these traces of parasites that you were always talking about.”
Hethke shipped the 13,000 fossils Huntley’s way from China. Huntley found traces of parasites from all throughout the Pearl River Delta in China — a place where Huntley spent some time doing research. About 10,000 years ago the climate was warming much like today.
“The climate is warming, the sea level is rising. We have that whole record of sea level rise preserved in this area,” Huntley said, “and they have a very complete very high resolution picture of how these environments were changing time, how the organisms were changing through that time, and so they had built this beautiful context to which to interpret the story.”
Huntley continues this research today at the University of Missouri. His wife now teaches in special education, and together they raise a 3-year-old daughter who just began attending preschool.
He still maintains connections with geologist across the world though. One connection in particular is with fellow geologist Hethke from Germany.
Hethke got to know Huntley while Huntley was working on his Ph.D. Whenever Huntley was in his office, Hethke said in a email, he would be searching for the small hole malformations on fossils created by the trematodes.
Hethke said one of the main things palaeontologists are interested in is the fossil groups change during different climates throughout our earth’s history. Episodes of climate change have occurred repeatedly.
Their results showed that trematode prevalence was significantly higher during the first 300 years of the postglacial sea-level rise in the Pearl River area, Hethke said.
“As an increase in parasite prevalence directly affects human health,” Hethke said, “and the fisheries, such studies are important to raise awareness.”
While Huntley still maintains his relationships with the researchers in Germany, he now teaches students at MU as well.
Kelly Hale, a graduate student at the University of Missouri who is working with Huntley to do research on paleoecology, has known Huntley prior. Huntley taught at St. Lawrence University for two years while Hale was an undergrad. She said that Huntley is interested in topics that she wouldn’t expect, for example listening to rap artists like, Drake.
“He has a wide interest in music which makes me laugh,” Hale said. “I was shocked that he liked some really great rap songs. I walk in here and I’m always bobbing my head and I’m really enjoying all the tunes he’s listening to from a wide variety from jazz to hip hop to rap it is great.”
Huntley and Hale, with undergraduate student Ronald Stuart, have collected dozens of fossils around Columbia. Once they’ve found a fossil the team will splice open it with a spinning saw in the lab. Afterwards they will smooth out the edges, dye it and look under a microscope.
Stuart said his research and interactions with Huntley can be summed up in one word — humbling.
Currently, Huntley has a box filled with 177 fossils of different species extracted from the ground.
“So, I spent a fair amount of time last spring semester, especially when my wife was out of town visiting family, I practically lived in my office,” Huntley said. “Going through and looking at those underneath the microscope and looking for traces.”
Huntley said the next few steps in his research are expected to be heavy in resources. He wants to use geochemical analysis to study if temperature played a role in the behavior of flatworms invading clams and mollusks.
He’s started to form relationships at the University of Missouri Research Reactor Center and apply for grants so he and his students continue their research.
“I think in general though the fossil record of parasites is one of the areas that is experiencing rapid growth right now,” Huntley said, “They are small, they don’t have skeletons, they don’t preserve very well. But we are finding interesting ways of tracking their history.”