Studying Microplastics in the Ocean
Is Plastic Killing Aquatic Life?
York College senior Ana Chew is a Biology major. She grew up in New London, Pennsylvania, a bucolic-but-land-locked township southwest of Philadelphia. She attends classes in a town surrounded by lush farms and forests. Neither community is what anyone would call seaside, or even marginally coastal, for that matter.
Nonetheless, Ana Chew recently spent three months living in Honolulu commuting to Ford Island, smack in the middle of historic Pearl Harbor, Hawaii. Her job for the summer was as a research intern in the National Oceanographic and Atmospheric Administration’s (NOAA) Young Scientist Opportunity program.
And how, exactly, does one from such decidedly non-marine surroundings land such a plumb assignment in one of America’s most iconic marine settings? By following her passion and working hard on her capstone independent research project at the College.
Chew is passionate about plastics in the ocean – especially very tiny particles of plastic and their impact on embryonic fish who often mistake those bits of plastic for food, swallowing them whole and sending ripples all across the food web, potentially even reaching humans.
The Enemy Within
These so-called “microplastics” that Chew studies are only just now coming into focus as a potential environmental hazard. Microplastics are interesting to researchers for a number of reasons. First, their small size makes them hard for small fish to distinguish from the typical plankton that usually comprise their diets. Scientists surmise that these tiny bits of otherwise indigestible plastic essentially clog the gastrointestinal systems, leading to malnutrition or even outright starvation. Likewise, microplastics are also known to attract and latch onto heavy metals and other molecules that are considered pollutants. It is thought that in the digestive tract these toxins leach out of microplastics and into the bloodstream. Those fish then grow and become food for some larger organism and the toxins get perpetuated.
The origin of microplastics is no mystery. They come from two sources, Chew explains. The first is the virtual flotilla of large plastics floating in the ocean. These could be anything from plastic bottles, buckets, and bags to toys and tools that have been discarded carelessly and washed into the sea. These plastics are not biodegradable and, if left undisturbed, will last hundreds of years in the water. Over time, however, due the ravages of wind, sunshine, and saltwater, they often break into even smaller pieces. When those pieces reach 5 millimeters or smaller, they become what Chew and fellow researchers would deem to be microplastics.
The second source is a little less obvious, but perhaps more insidious. These microplastics are manufactured to be small from the start. They range from tiny bits of glitter on a party hat to the fine plastic beads used in household soaps and toothpastes as abrasives. Many of the products millions of us use every day contain billions of tiny microplastics to improve their scrubbing and exfoliant effects. These beads get washed down the drain and right into water systems all across the world. Once in the watershed, they head downstream and straight into the ocean.
"Independent research is something special about the York experience. Ana made the most of her opportunity.” — Bridgette Hagerty, PhD
And so it came to be that, early in her junior year, Chew began working as a research assistant with Wendy Boehmler, PhD, a professor of molecular and cell biology. Years earlier, Boehmler had begun to study the neurological systems of zebra fish, a popular model in biological research because they are vertebrates, like humans, and the larva are more or less transparent, for easy study under the microscope.
Here, in Boehmler’s group, Chew began to learn the fundamentals of biological research and was first encouraged to think independently about how she might apply those skills in a research project of her own making. Such independent research projects are an opportunity all York biology students enjoy, pairing them with a scientific mentor who instills in them the key skills of research and guides them as they do original work. They write a research proposal and work with faculty to shape their research.
“Independent research is something special about the York experience,” says Chew’s academic advisor, Bridgette Hagerty, PhD, a professor of biology. “Ana
made the most of her opportunity.”
In contemplating her project, Chew first came up with the notion of studying the impact of certain environmental toxins common to microplastics. She brought her ideas to Boehmler – a specialist in neurobiology, not toxicology. The mismatch caught Boehmler off guard at first. “Her ideas were a bit out of my comfort zone, but she was passionate and eager to work on microplastics, so we worked together to craft a project,” Boehmler says. “Actually, Ana kind of pushed me in a new direction, which is nice.”
Chew’s job is to separate the particulates and to categorize them. She’s intently interested in the plastic bits and the embryonic fish. She carefully dries, organizes, and photographs the microplastics and details them in a database. She cataloged some 12,000 plastic samples during the summer.
Her specific experience working with Boehmler on embryonic zebra fish was what first caught the attention of Chew’s advisors at NOAA. They were in the midst of a project to learn if there was an increase in microplastics in embryonic fish surrounding Hawaii over the past 20 years.
As a baseline, the NOAA scientists had data from several dozen water samples – known as “tows” – along the west coast of Hawaii taken two decades ago. As the moniker implies, each tow involved a research vessel dragging a mesh to collect samples of the particulates in the water. Particulates can include everything from sand, insects, and plankton to plastics and, of course, embryonic fish. The NOAA team is doing a number of present-day tows to compare how things have changed in the ensuing 20 years.
Chew’s job is to separate the particulates and to categorize them. She’s intently interested in the plastic bits and the embryonic fish. She carefully dries, organizes, and photographs the microplastics and details them in a database. She cataloged some 12,000 plastic samples during the summer. And, just as carefully, she separates, identifies, and organizes the embryonic fish found in each tow. The sorting of embryonic fish alone has been quite eye-opening for Chew.
“There is way more variety of fish in Hawaii than in Pennsylvania,” she says.
The tows are not done indiscriminately. Chew’s mentors at NOAA are specifically combing through areas known as “slicks,” surface waters that appear like darker patches on the surface of the water. These are not oil slicks, but rather areas of convergence where ascending water from below meets descending water from the surface. It is here, in these nutrient-rich slicks, where embryonic fish congregate to feed and to grow. Microplastics naturally collect here, as well, and the line between plastics and embryonic fish is clearly drawn. For Chew and her NOAA colleagues, it is an ideal place to gather data.
“In some samples, we’re finding that plastics out-number larval fish by seven to one,” Chew says of some preliminary findings.
Another of Chew’s mentors, York professor Jessica Nolan, PhD, a marine biologist by training, says such findings raise the natural question of what can be done about the problem of microplastics. She says that, among the many lesser suggestions, the only viable possibility she sees is to allow fewer plastics in the ocean. As evidence, she points to studies that show microplastics tend to clump together – to “flocculate,” as Nolan puts it – which then sink to the bottom where they can remain for long periods of time. With fewer plastics entering the water, she says, the ocean might possibly cleanse itself.
“The sort of baseline research Ana is doing is important for building the case for new policies that would limit plastics in the environment,” Nolan says.
Reflecting on the connection between her experiences at York College and in Hawaii, Chew says that she is looking forward to continuing her research in her senior year. With graduation so near, she says she would love to pursue microplastics research in graduate school or, perhaps, in a professional capacity. In that regard, she is grateful to her mentors at York, professors Boehmler, Hagerty, and Nolan, for inspiring her and giving her the opportunity to pursue her interests so freely.
“My advice to anyone at York interested in research is to find and really connect with your mentors. They were in my corner and really supported me,” Chew says.
They, in turn, are equally effusive about Chew.
“Ana has been able to carve out her niche through her own initiative and her independent research,” Nolan says.
“Ana came to me with ideas, passion, and skills – exactly what you want in a student,” Boehmler adds.