Marine Scientists, Students Find Widespread Floating Plastic Debris in North Atlantic Ocean
Undergraduates working through the Sea Education Association (SEA) play major role in discovery
Despite growing awareness of the problem of plastic pollution in the world's oceans, little solid scientific information has existed about the nature and scope of the issue.
This week, a team of researchers from the Sea Education Association (SEA), Woods Hole Oceanographic Institution (WHOI), and the University of Hawaii (UH) has published results in the journal Science of a study of plastic marine debris based on data collected over 22 years by undergraduate students.
The western North Atlantic contains high concentrations of plastic debris, comparable to those observed in the region of the Pacific commonly referred to as the "Great Pacific Garbage Patch."
More than 64,000 individual plastic pieces were collected at 6,100 locations sampled yearly over the course of the study. A plankton net was used to collect plastic debris as well as biological organisms at each station.
"We now have the first long-term, regional-scale scientific study of this phenomenon," says Don Rice, director of the National Science Foundation (NSF)'s chemical oceanography program, which funded the research.
"This unique study leaves us with a big mystery and a haunting question, however: What happens to all that plastic once it gets to the central gyre [current]? And how does it interact with deep-sea biology?"
The highest concentrations of plastic were observed in a region centered at 32°N (roughly the latitude of Atlanta, Ga.) and extending from 22-38°N latitude.
"Not only does this important data set provide the first rigorous scientific estimate of the extent and amount of floating plastic at an ocean-basin scale," says SEA scientist Kara Lavender Law, the Science paper's lead author, "but the data also confirm that basic ocean physics explains why the plastic accumulates so far from shore."
Numerical model simulations by Nikolai Maximenko (UH) explain why surface currents cause the plastic to accumulate in this region.
A surprising finding is that the concentration of floating plastic debris has not increased during the 22-year period of the study, despite the fact that the plastic disposal overall has increased substantially.
The whereabouts of the "missing plastic" is unknown.
"The analysis provides a robust scientific description of the extent of plastic pollution to date, which can be used to make better management and policy decisions, and to inform popular perceptions of this issue," says SEA Dean Paul Joyce.
A companion study published this week in the journal Marine Pollution Bulletin details the characteristics of the plastic debris collected in these tows.
Most of the plastic is millimeters in size and consists of polyethylene or polypropylene, materials that float in seawater.
There is evidence that biological growth may alter the physical characteristics of the plastic over time, perhaps causing it to sink.
"I think some of the big questions are colonization: what actually lives on these pieces of plastic?" says scientist Chris Reddy of WHOI, a co-author of both papers.
"To what extent are ocean currents moving the small life on these plastic particles around the ocean?"
Data continue to be collected aboard SEA's sailing research vessels in both the Atlantic and Pacific Oceans by undergraduate students in the SEA Semester program.
A dedicated research cruise, Plastics at SEA: North Atlantic Expedition, recently investigated the eastern boundary of the Atlantic plastics accumulation zone.
"The several thousand SEA Semester undergraduate students who helped collect and count plastic debris over the decades have been essential contributors to this work," says SEA President John Bullard.
"They have gained a much fuller understanding of the oceans and the role humans play both in their present and future."
To learn more about Sea Education Association's mission and programs, please visit their website.
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2017, its budget is $7.5 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives more than 48,000 competitive proposals for funding and makes about 12,000 new funding awards.
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