It’s an invisible problem on a global scale.
Drinking straws, shopping bags and other plastic litter contaminating our beaches and oceans are easy to see, but true microplastics – particles ranging in size from 5 millimeters to those too tiny for the unaided human eye to perceive – are entering the food chain, potentially causing damage to marine animals and human bodies.
That’s why researchers in Gordon Taylor’s lab at Stony Brook’s School of Marine and Atmospheric Sciences (SoMAS) are searching for these unseen ocean contaminants with the help of two high-powered instruments.
Students and research associates are using a laser Raman microspectrophotometer to help them explore the chemical composition of microplastics that pose a global threat to marine environments, and an atomic force microscope that can image molecules and the tiniest of organisms.
“To the best of my knowledge, we are the only environmental or marine science lab in the United States to have such capable instruments, aside from Woods Hole Oceanographic Institution in Massachusetts,” said Taylor, a Professor of Oceanography at SoMAS and Director of the NAno-Raman Molecular Imaging Laboratory (NARMIL).
In simplified terms, the microspectrophotometer is a laser-based device that measures the colors of light scattered from sample materials and provides chemical information. The Raman instrument is capable of focusing a laser beam down to a third of a micrometer, which is 200 times less than the width of a human hair.
The atomic force microscope is capable of resolution down to a tenth of the width of a single DNA molecule, which enables visualization of proteins and the surface of cells and viruses.
With these tools, Taylor said, researchers can produce three-dimensional chemical maps; software then reconstructs the images in a process similar to how medical tomography interprets a CT scan.
As technology evolves, Taylor emphasized, researchers increasingly require significant funding to invest in the equipment necessary for meaningful results. “Basic research involves constant auditioning to get money,” he said.
Taylor’s Ph.D. student, Luis Medina, is studying samples taken from New York Harbor out into the Atlantic, off the Long Island coast, as well as in the Arctic, Antarctic, Caribbean Sea and the coast of Mexico. Medina has also been working on a National Geographic grant investigating microplastics in the coastal waters of his native Venezuela with help from research support specialist Tatiana Zaliznyak. Their work is in its early stages.
“For my research, I am very fortunate to have access to a confocal Raman microspectrophotometer,” Medina said. “This technology is unmatched for exploring small-scale interactions among microplastics, microorganisms and the environment. Understanding these interactions is fundamental to addressing unanswered questions about effects of microplastics pollution in our oceans.”
According to Taylor, the jury is out on whether or not ingesting microplastics poses a serious health risk. The concern is that microplastics can potentially concentrate other contaminants such as dangerous hydrocarbons, pesticides, and PCBs, which are known to be absorbed by plastics.
“We know that many types of marine animals concentrate plastic contaminants from their environment,” he said. “Microplastics can act as vehicles for harmful chemicals to move up the food chain. The technology being developed in NARMIL will provide a means to improve our understanding of microplastics behavior in the ocean.”
“As an analytical and environmental chemist, I am delighted to see this very clever combination of Raman spectroscopy and atomic force microscopy applied to the pursuit of a significant contemporary environmental problem, said SoMAS Dean Paul Shepson.
“Professor Taylor’s group is leading the world toward a better understanding of human impacts on the Earth’s oceans,” Shepson said.
— Glenn Jochum