Tatiana Rynearson
URI Graduate School of Oceanography
Associate professor, oceanography

To the non-scientist, the idea sounds farfetched — microscopic organisms drift freely in the currents and tides of the world’s oceans, generating half of the oxygen we breathe.

These tiny, one-celled plants — phytoplankton — undergo photosynthesis in the sunlit waters of the ocean’s surface, drawing down enormous amounts of carbon dioxide and pumping oxygen into the atmosphere. Unseen by the naked eye, they also form the base of the marine food web, eaten by tiny floating animals, zooplankton, which in turn serve as a food source for the next level of predators.

Consequently, climate change or not, these organisms hold considerable interest for scientists and are the subject of much study.

“We want to know what they do and how they work,” says Tatiana Rynearson, whose research focuses on plankton ecology and evolution. “Then, you add in climate change, and there is the concern of how they are going to respond. What drives their productivity, what regulates their success over time?

“It’s much like if you are running a farm and raising cows, what’s going to happen to the grass if there is a drought and you don’t have enough to feed the cows? In a similar sense, phytoplankton are the grass of the ocean. How are they going to respond to higher temperatures? Ocean acidification? And in some cases, lower levels of nutrients?”

Rynearson says she takes three primary approaches to her investigations, first looking at evolutionary dynamics. Different species have different adaptations. And, from an evolutionary perspective, her interest lies in how the different species of phytoplankton adapt to their specific locations and how much genetic exchange takes place between locations.

Her second focus looks at the successful metabolic pathways the organism employs. Using cutting edge molecular tools, Rynearson probes inside the cells to gauge what pathways are turning on and off, and if and how that alters their growth.

“We want to know how they respond to the environment,” Rynearson says. “We start to ask who might be more successful under different scenarios. The new technology is so cool — we can probe inside a cell to assess its health, see whether it’s stressed when there is not enough light or nutrients.”

The third avenue seeks to understand interactions between the groups of plankton — such as between phytoplankton and bacteria, both of which exist in what Rynearson describes as a symbiotic relationship. As with any set of individuals living in a group, a change in context can change the nature of interaction.

“What if the phytoplankton are stressed?” asks Rynearson. “Will the bacteria sense the weakness, start to attack and hasten their downfall? We think the kinds of interactions between phytoplankton and bacteria might change depending on the context.”

Specifically, in Narragansett Bay, Rynearson says research indicates there are seasonal changes in both cold and warm water species. She describes the cold water species as highly productive and suspects they will retreat and lessen in abundance as water temperatures warm, a pattern that follows the current seasonal shift. The questions that follow are whether and how this change will affect the Bay’s food web.

Rynearson says most of her work, in one way or another, has benefitted from the Rhode Island NSF EPSCoR grant — most broadly through the use of the shared core facilities. She has mentored Summer Undergraduate Research Fellowship (SURF) students, trained EPSCoR graduate fellows, and secured RI Science and Technology Advisory Council (STAC) grants, which have yielded publications and launched other grants.

The students gain tremendous access to scientific methods through active, hands-on research. Rynearson describes her role as a guide: “I love it — they are a group of super creative, really motivated students who can be unleashed on a problem.”

One of her STAC projects funded a postdoctoral student who arrived in Rhode Island from Delaware. When the project ended, he took a job in a National Oceanic and Atmospheric Administration (NOAA) facility in the state. He trained here and stayed, the STAC project serving as his entry point to the Ocean State. At the graduate and undergraduate levels, students in the Rynearson lab have secured internships through STAC grants and trained on cutting edge molecular work, and gone onto careers in the biotech industry.

“One paper may not change the trajectory of policy, but if we have a list of 20 publications that all reach the same set of conclusions, then we can say, globally, here are the changes we expect.”

Rynearson also has taken advantage of professional development opportunities through the Metcalf Institute for Marine & Environmental Reporting SciComm Exchanges, science communication events sponsored by RI EPSCoR.

“The science communication events and workshops have been enormously helpful to me and my lab,” she notes. “I’ve sent grad students and post docs. Most recently, the SciComm on how to testify at a congressional hearing was new information for me — I had no idea. It’s also important continuing education that students don’t get in their normal courses. It makes us better scientists.”

Stepping back and contemplating the impact of her research, Rynearson says no single project or outcome is likely to change minds or spur leaders to act. However, she figures, her findings will add to a continually growing body of work and help fill in the unknowns. The information produced by the RI EPSCoR community as a whole can help leadership adapt policy to projected change; for example, less phytoplankton in Narragansett Bay could lead to less fish, which means adjusting to the new normal.

“Capstone conclusions are always supported by many, many research projects,” she explains. “One paper may not change the trajectory of policy, but if we have a list of 20 publications that all reach the same set of conclusions, then we can say, globally, here are the changes we expect.”

Story and photo by Amy Dunkle | RI NSF EPSCoR