New Study Finds That Microplastics Reduce the Efficiency of Removing Carbon Dioxide from the Atmosphere
MES/COS/CEE Professor Aron Stubbins co-authored a new study, published in Marine Chemistry, which shows that microplastics slow down the ocean’s natural carbon sink process. This is reducing the ocean’s ability to remove carbon dioxide from the atmosphere, which impedes it from helping offset the climate crisis.
This article originally appeared on Northeastern Global News. It was published by Cynthia McCormick Hibbert. Main photo: A new study shows that microplastics may reduce the ocean’s ability to help offset the climate crisis by hampering carbon sequestration. Photo by Matthew Modoono/Northeastern University
What is ‘marine snow’? And how do microplastics slow the rate at which carbon is pulled from the sea surface to the depths?
It turns out plastics in the ocean do more than suffocate turtles, fish and other marine life.
A new study co-authored by Northeastern researcher Aron Stubbins shows that microplastics may reduce the ability of the ocean to help offset the climate crisis by slowing down the rate at which carbon is taken from the sea surface to the depths.
For millennia, the ocean has been part of a carbon sink process in which dead phytoplankton clump together and fall into the deep ocean in showers of what look like “marine snow,” says Stubbins, a professor of marine and environmental science.
The resulting carbon sequestration is a marine version of how trees and plants on terrestrial Earth take carbon from the atmosphere and store it in soil, he says.
But research by Northeastern shows that microplastics in the ocean are slowing the process down by making the “marine snow” more buoyant, Stubbins says.
Aron Stubbins, professor of marine and environmental sciences, inspects microplastics from the open ocean in the Mugar Life Sciences Building. He co-authored a study showing they slow the descent at which carbon-removing “marine snow” descends to the deep ocean. Photo by Matthew Modoono/Northeastern University
“Plastics want to float. If phytoplanktons grow on microplastics in biofilms, instead of as free living organisms, that changes the buoyancy of the phytoplankton when they die,” Stubbins says.
“Basically, the plastics are slowing down the sinking rate of the marine snow, which is potentially reducing the efficiency with which the ocean can remove carbon dioxide from the atmosphere,” he says.
For the study reported in Marine Chemistry, researchers grew the tiny one-celled plankton in tanks with and without exposure to microplastics.
Then they held their own version of a race to the bottom.
The researchers put the regular clumps of phytoplankton in one measuring cylinder filled with seawater and put the phytoplankton entwined with microplastics in another cylinder.
“You timed how quickly they sank,” Stubbins says. “The ones with the plastics were slower, by about 20%.”
Read full story at Northeastern Global News