Plastic debris field in Atlantic Ocean smaller than it should be: study

Researchers have mapped out a previously undefined field of plastic debris floating in the western North Atlantic Ocean – but their findings, published in a new study, raise as many questions as they solve.

For example, the concentration of floating plastic has not increased during the 22-year period of the study, despite the fact that the amount of plastic disposed of in the ocean has increased substantially. The whereabouts of the “missing plastic”, the study said, are unknown.

One possible answer: Since most of the plastic debris is only millimeters in size, it’s thought that biological growth may alter the physical characteristics of the plastic over time, causing it to sink.

The study – written by researchers from the Sea Education Association (SEA), Woods Hole Oceanographic Institution (both of Woods Hole, Mass.), and the University of Hawaii (UH) – is the result of a sampling of over 64,000 individual plastic pieces from 6,100 locations during 22 years, and appears in the latest issue of the journal Science.

According to the study, the debris in the north Atlantic has been found to contain high concentrations of plastic, comparable to those observed in the so-called “Great Pacific Garbage Patch” region of the Pacific Ocean.

Less mysterious than the fate of the missing plastic is the fact that the highest concentrations of debris were observed in a region centered at 32°N (roughly the latitude of Atlanta, Ga.) and extending from 22-38°N latitude. Numerical model simulations of surface currents undertaken by UH predicted that the plastic would accumulate in exactly this region, the study said.

“The analysis presented in this Science article 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,” said the SEA’s Dean Paul Joyce.