Ocean garbage patches are not growing

so where is all that plastic going?

By Larry Greenemeier

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Researchers have been visiting locations in the western North Atlantic Ocean and Caribbean Sea for more than two decades to better understand the large patches of plastic that have formed there. Although the mysteries surrounding exactly how the plastic gets to these locations, where it comes from and what impact it’s having on marine life remain unanswered, a team of scientists has now published perhaps the most analytical study of the patches to date based on data collected by research vessels over a 22-year period, between 1986 and 2008.

The researchers from Sea Education Association (SEA), Woods Hole Oceanographic Institution (WHOI) and the University of Hawaii (UH) found, among other things, that the amount of plastic picked up by the researchers’ nets remained pretty stable over the years, despite society’s increased production and consumption of plastic, according to research published in Thursday’s issue of Science Express.

More than 64,000 individual plastic pieces were collected at 6,100 locations that were sampled yearly over the course of the study. To collect these data, ships towed nets along the water’s surface at each location, and researchers used tweezers to pick the small plastic bits out of the algae and other collected material. More than 60 percent of the surface plankton net tows collected buoyant plastic pieces that were typically millimeters in size. The highest concentrations of plastic were observed in a region centered at roughly the latitude of Atlanta.

By combining their measurements with a computer model of ocean circulation, the researchers report that this concentration of plastic occurred in an area where wind-driven surface currents were converging. The researchers think this helps explain why the debris accumulates in this particular region, so far away from land. The authors propose a handful of possible explanations for why the patch hasn’t grown rapidly since its discovery. The plastic there may break up into pieces too small to be collected by the nets, or it might be sinking beneath the surface. Or, it might be consumed by marine organisms. More research will be necessary to determine the likelihood of each scenario, the researchers conclude.

Scientific American