School Email Exchange

Why are most of the pieces of plastic you’ve been finding so small?

Posted on November 06 2012

Question submitted by Bainbridge High School

This photo was taken when we were in the largest concentration of plastic so far, dubbed the “windrow tow”.  I pointed my camera straight down off the side of the Seamans. There are some zooplankton but it is clear there are many very small pieces of plastic.

As has been mentioned in previous answers, the UV rays from the sun along with wind and wave action, and possibly the bacteria living on them, work on floating plastics to continually break them down.  Marina Garland, who is doing research on microscopic plastics, explained that depending on the type of plastic, it breaks down to a certain microscopic size then persists in the ocean indefinitely.  Being petroleum-based, these microscopic pieces (as well as large pieces) not only retain some of the additives from their production, some of them toxic, they also absorb hydrophobic toxins from the ocean around them.

Seen under a microscope, filaments of plastic loop around copepods.  Photo by Marina Garland