Joselynn Wallace
University of Rhode Island
Ph.D. candidate; biological and environmental sciences
RI EPSCoR graduate fellow & summer support

On track to graduate with her Ph.D. in May 2017, former RI NSF EPSCoR graduate fellow Joselynn Wallace isn’t exactly sure where her journey will lead after immersing herself in the study of diatoms, the single-celled, microscopic algae known for their distinctive glass shell.

But, she says, her end goal remains constant and fixed: “I’m just planning on casting a wide net. As long as I’m doing something that I feel is contributing to the body of knowledge as a scientist, I’ll be happy.”

Wallace appreciates the magnitude of her achievements in higher education, particularly since neither of her parents attended college and her father did not graduate from high school. However, both parents value education and instilled the belief that it was the key to advancement.

She says she remembers her father, an auto mechanic, coming home from work, his hands covered with grease: “He would say if you study and work hard, you won’t have greasy hands.”

Wallace grew up in Pawtucket and Central Falls, RI, graduated from Cumberland (RI) High School in 2002, and enrolled at URI. A microbiology major, she says the field first drew her interest in elementary school when a visiting microbiologist gave the young students petri dishes and swabs to collect samples.

“I went to the most disgusting place I could think of, the bubbler, and swabbed the rim,” Wallace recalls. “She brought the plates back the next day. I still remember how it smelled.”

Wallace credits Deborah Grossman Garber, who taught her URI 101 class, with encouraging her to apply for the Coastal Fellows Program, which provides undergraduates with hands-on experience in their fields of interest. She ended up working in the lab of Professor David Rowley, College of Pharmacy, throughout her undergraduate years.

Wallace says Rowley’s area of expertise — marine natural products chemistry, antibiotics drug discovery, and marine microbial chemical ecology — struck a chord with her and bridged the gap between theory and practice.

She graduated with her bachelor’s in 2006 and spent five years working for a small biotech company in Worcester, Mass. She was involved in several projects, including one that looked for new compounds that inhibit the ways bacteria make fatty acids. She put to use such skills as polymerase chain reaction (PCR), a process used to make copies of a DNA sequence, and cloning.

Wallace says she was struck by the power and potential of the molecular tools available: “That got me thinking how cool it would be to answer questions about what was going on in the ocean. Climate change is the issue of our time.”

Looking for a Ph.D. program that would combine what she had learned and what she wanted to pursue, Wallace found Associate Professor Bethany Jenkins, URI College of the Environment and Life Sciences (CELS), cell and molecular biology. She says the Jenkins lab combined her interests — marine microbes and climate change — and she began graduate school in 2011.

The climate change impact

Wallace’s dissertation on diatoms explores how their gene expression changes under different carbon dioxide (CO₂) levels; how climate change affects this tiny organism that contributes oxygen into the atmosphere through photosynthesis, responsible for every fifth breath we take.

In particular, her work looks at three species of Thalassiosira diatoms from different parts of the ocean (T. weissflogii, T. rotula, and T. oceanica) and studies them under four distinct sets of CO₂ conditions — pre-industrial, ambient, predicted climate change levels, and exceptionally high levels.

“What we’re finding is that one open ocean species, T. oceanica, is really sensitive to high CO₂, but we don’t know if that holds across diatom species,” Wallace says. “When we compare the current ambient versus future projected levels, the growth rates decrease pretty drastically.”

More work needs to be done and data analyzed, but the open ocean diatom species warrant study, according to Wallace. Unlike coastal species influenced by tides, upwelling or runoff, those in the open ocean may not handle the stress of climate change as well because they are not regularly exposed to fluctuating levels of nutrients, acidity or temperature. Any changes in abundance or quality will carry an impact that ripples throughout the ecosystem, from the microscopic organism to the mammoth whale.

Throughout her graduate studies, Wallace has received summer support from Rhode Island NSF EPSCoR in addition to her 2012-13 academic year fellowship: “It’s been huge in terms of being able to focus on my work. During the year, with the fellowship, you don’t have to teach and can plough through, getting as much analysis done as possible. And, there’s not really a good way for grad students to get paid during the summer.”

Having access to the Center for Computation and Visualization (CCV) at Brown University as part of the RI EPSCoR community also has been instrumental, allowing Wallace to handle the enormous data files generated by sequencing gene fragments. If not for the CCV and its server capacity, she says, it would take weeks or months for her to run the data.

With the experience gained during her Ph.D. degree work, Wallace says she hopes to pursue ways to harness the technology and use the data gathered to make better projections of the climate change impact.

The pressing question, she says, is: “How can we as molecular biologists make the information more useful?”

Story and photo by Amy Dunkle