Student Profile: Seanna Forrester

SoMAS graduate student Seanna Forester

Seanna Forrester is a Ph.D. student in Daniel Knopf's lab. She graduated from Stony Brook University with a double major in Chemistry and Environmental Studies, and was the recipient of an award for excellence in undergraduate research for her work on “The Effect of Organic Surfactants on the Heterogeneous Ice Nucleation of Aqueous Salt Droplets.”

Seanna's interest in atmospheric chemistry reseach was sparked when she took a course on air pollution taught by Dr. Knopf during her Junior year at Stony Brook.

"I loved learning about different photochemical reactions, about the ozone hole and the chemical processes behind it," she said. "I’ve always cared about the environment and enjoyed chemistry. Atmospheric chemistry combines those two interests very well."

Seanna then spent four semesters and a summer in the Knopf lab studying how organic coatings affect an aerosol particle's ability to act as the nucleus for the formation of an ice crystal in the atmosphere. Natural sea salt particles can have an organic coating that comes from the microscopic layer of organics on the surface of the ocean created by decomposition of phytoplankton or other biological organisms.

In the lab, Seanna examined two different organic coatings--nonadecanol and nonadecanoic acid--and was able to relate their molecular properties to their effect on ice nucleation efficiency.

She found that the organic coating nonadecanol can induce freezing of water at much higher temperatures than expected from homogeneous ice nucleation. This suggests that a monolayer coating on the surface of a cloud droplet in the upper troposphere can induce ice nucleation at higher temperatures than without the coating. Better understanding of the mechanisms of ice cloud formation could greatly improve understanding of the global radiative budget and help refine climate models.

For her Ph.D. research, Seanna will study the chemical transformation of aerosol particles using a chemical ionization mass spectrometer and Dr. Knopf is delighted that she chose to stay in his lab despite having other graduate school options. "Seanna is a hard working and very focused student who tries to get to the bottom of the problem," said Dr. Knopf. "I'm sure her research project will yield very exciting new science crucial for a better representation of the role of particles in the atmosphere."

"Research is my passion," said Seanna. "It's what I want to keep doing after graduate school, whether in academia or in a national lab or government job," she said.