As the scientific community recognizes that massive floating debris fields made primarily of plastic are adrift in the world’s oceans, many wonder how dangerous that plastic is, and how long it will take to disappear.

A trio of Carroll College students recently developed a mathematical model to attempt to answer those questions and claimed top honors in an international contest in the process.

Carroll’s three-person team of math majors, Brittany Harris and Kyle Perkins, and chemistry major Chase Peaslee, recently received an “outstanding” ranking in the Interdisciplinary Contest in Modeling, one of just four out of more than 350 teams in the competition to earn the top ranking. Two Chinese universities and Lawrence University in Wisconsin also had teams claim outstanding ranks.

The students were tasked with developing a model analyzing some aspect of the garbage field, its possible effects on the marine environment and what government policies might be enacted to mitigate those effects. They developed a way to measure how long it would take the sun to biodegrade all the plastic afloat in a given debris mass.

“Sunlight comes down in a unit of energy per square meter, and there are so many plastic bonds that can be broken per second,” Peaslee said. “We were able to show that each piece of a certain size will break down at a certain rate, and that all the pieces will break down in this much time if no more plastic is put into the ocean.”

The students had a 96-hour period in February to complete a 10-page paper spelling out their model, with no outside help from instructors or advisers.

“We knew we had great math and great chemistry, but we were a little worried about the writing and whether our final product would be up to par,” Harris said.

She noted that not only will it take a long time for the sun to break down all the plastic afloat in the ocean, but that the process of degrading stops when the plastic molecules reach a dangerous size.

“The size of the molecules has important implications because they seem to stop degrading from photochemical means as they approach the size that’s comparable to natural cyano-bacteria,” she said. That raises the possibility of plastic residues finding their way into the food chain.

Math professor Holly Zullo, a faculty mentor for the students, said they didn’t do the project to earn credit for a particular class, and that notoriety is the only prize that comes with high marks in the contest. She said earlier that Harris is the first woman from Carroll to qualify for an outstanding rank in the contest, and that the Carroll team may be one of just a few with women members that have achieved the ranking in the history of the contest.

“This is strictly their own interest that motivates them,” she said. “I like the internal drive.”

In a meeting at the Capitol Monday afternoon, Gov. Brian Schweitzer quizzed Harris and Perkins on their paper.

“Politicians don’t change the world,” he said. “Change is created by scientists. They are the ones that will create the ideas that will solve the problems of tomorrow.”

Reporter John Harrington: 447-4080 or

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