The most common method for measuring plastic in the ocean is the surface plankton net tow.  More recent studies done by SEA indicate that this method may dramatically underestimate the total amount of plastic in the upper ocean because wind energy can mix buoyant plastic down away from the surface.

Neuston Net

Plastics Chart
Distribution of plastic marine debris collected in 6136 surface plankton net tows from 1986-2008 in the western North Atlantic Ocean and Caribbean Sea. Symbols indicate the location of net tows; color indicates the measured plastic concentration in pieces per square kilometer. Black stars indicate tows with measured concentration greater than 200,000 pieces per square kilometer. Symbols are layered from low to high concentration. Figure courtesy of the Journal Science

Plastic Distribution

Plastics Map
This is representative sample of the plastic pieces collected in a single surface plankton net tow.  The majority of plastic pieces are small less, than 1 cm in length and less than 0.15 g in weight, and less dense than seawater. Credit: K. L. Law et al. Science

Plastics Pieces

Plastics Pieces

Despite growing awareness of the problem of plastic pollution in the world's oceans, little solid scientific information existed to illustrate the nature and scope of the issue. This week, a team of researchers from Sea Education Association (SEA), Woods Hole Oceanographic Institution (WHOI), and the University of Hawaii (UH) published a study of plastic marine debris based on data collected over 22 years by SEA undergraduate students in the latest issue of the journal Science.

A previously undefined expanse of the western North Atlantic has been found to contain 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 6100 locations that were sampled yearly over the course of the study. A surface plankton net was used to collect plastic debris as well as biological organisms at each station. 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. Numerical model simulations by Nikolai Maximenko (UH) explain why surface currents cause the plastic to accumulate in this region.

First Author Kara Lavender Law

Kara

Kara received her PhD in physical oceanography from Scripps Institution of Oceanography, and developed an interest in marine debris while teaching and sailing with SEA. Kara is on the oceanography faculty at SEA Read More...