The Scientist Tackling the Ocean Food Chain
WHY YOU SHOULD CARE
As oceans change, some of the most vital organisms to watch escape the naked eye.
By Carly Stern
Sonya Dyhrman’s most treasured childhood days were those she spent clamming on the Puget Sound. As Dyhrman grew older, the times of year she could go out on the water became noticeably shorter. Clams were getting contaminated by “red tide” — when toxic algae blooms discolor coastal waters and make organisms like clams poisonous to eat.
Dyhrman, a Washington state native, had always felt called to the ocean. She quickly developed a direct understanding of how tiny organisms could affect everyday life. “I’m so fascinated by a world you can’t see,” she says.
The 47-year-old earth and environmental sciences professor at Columbia University has remained captivated by the study of life too small for the naked eye. Dyhrman’s pioneering work on microbes and microbial interactions is examining just how vulnerable the global food chain may be to climate change. Much of the correlation between food and global warming has centered on what humans consume: meat or plants, carbs or protein. But Dyhrman has gone below the surface — below the sea, specifically — to study the impact of climate change on the most elemental base of the food chain.
The objects of her fascination — marine microbes — are the heartbeat of the ocean ecosystem, as the food that zooplankton and shellfish consume. Dyhrman and her team at Columbia use specific strands of big data, like computational biology and genomics, to measure this changing pulse of the ocean as it’s exposed to warming, acidification and deoxygenation. Because of recent technological advancements unlocked by the Human Genome Project, Dyhrman and her team are able to ask and answer questions she never thought possible.
It would be as if you took the Amazon, and instead of it being dominated by jungle trees, all of a sudden it was nothing but grass.
As climate change accelerates, bearing witness to these interactions — ones that “quite literally make our planet inhabitable,” she says — brings a sense of urgency. And her research so far shows climate change will create “winners and losers” at the foundation of the food chain, with uncertain results for your favorite seafood.
The explorer bug has always been in Dyhrman’s bones — and her genes. Her grandparents were pioneers in Alaska in the 1930s, and the rest of the family settled in the Pacific Northwest. Dyhrman grew up hiking and exploring tide pools with her father, a geologist, while her mother worked as a children’s librarian and a school district administrator.
She participated in a high school marine science program and got hooked. “I could scuba dive before I got my driver’s license,” Dyhrman says with a laugh. The biology major managed to find her way back to the (chillier) water as an undergraduate at Dartmouth College in New Hampshire, rowing crew — she was summoned while crossing the quad due to her 5-foot-11 stature — and doing tropical marine biology field programs in Jamaica and Costa Rica. After graduation, she set off to earn her Ph.D. from Scripps Institution of Oceanography in Southern California, trading the East Coast formality and history she’d grown to love for the beauty of West Coast sunsets.
The vastness of the ocean beckoned, and she’s yet to come up for air. Her passion is fervent — and her knowledge of marine microbial literature is encyclopedic, adds Gwenn Hennon, an assistant professor at the University of Alaska, Fairbanks, who was a postdoctoral research scientist in Dyhrman’s lab. When Dyhrman isn’t teaching students, she spends time using genetic information from ocean samples to determine which microbes are present and what they are doing — “almost like CSI for the ocean,” she explains.
Recent advancements have revealed that marine microbes can actually talk to each other in a special chemical language, which opens up a novel slew of research questions. “It’s like we are trying to learn to understand a language that only these microbes speak in order to eavesdrop on their conversations,” Hennon says. Their research showed that certain phytoplankton and “helper” bacteria are usually friendly until exposed to global-warming-sparked ocean acidification — when their relationship can sometimes shift to become more antagonistic, according to Hennon.
All of these conditions are changing rapidly. “One of the most powerful tools we have for understanding how climate is going to affect the ocean is modeling,” says Kathleen Ruttenberg, a professor of oceanography and earth sciences at the University of Hawaii at Manoa, who collaborates with Dyhrman.
Dyhrman chases after data to fuel those models. She co-authored an MIT study suggesting that rising carbon dioxide levels might change which microbe species dominate the North Pacific Ocean. And Dyhrman can determine what allows one organism to outcompete another for limited available nutrients, explains Ruttenberg.
She’s at the forefront of a field that’s increasingly attracting major philanthropic investment given microbes’ importance not just to the food chain but also to absorbing carbon dioxide from the atmosphere.
While it’s easy for people to dismiss these radical shifts because they can’t see them with their own eyes, Dyhrman likens their magnitude to changes on land: “It would be as if you took the Amazon, and instead of it being dominated by jungle trees, all of a sudden it was nothing but grass,” she says.
Dyhrman is among a cadre of marine scientists jumping onto a never-before-seen type of treadmill as its pace accelerates beyond their control. As she studies these obscure sea interactions, she’s tasked with not only figuring out how to sustain a run — but also predicting how the incline will continue to change beneath her feet.