Plastics at Sea

I will never experience a Thanksgiving quite like the one I did five years ago.  I was just returning from a semester of sailing from Massachusetts down into the Caribbean conducting marine science research aboard the Corwith Cramer.  The friends I made and experiences we shared were unforgettable.  I had this adventure with Sea Education Association (SEA), which is an amazing educational sailing program that focuses on a variety of marine sciences.

My best mate and me!

Some rough seas in the Northern Atlatnic

The Corwith Cramer

If you follow news about plastics in the ocean, you may be aware that in addition to the Great Pacific Garbage Patch, there are four other "garbage patches" in the oceans.  SEA has conducted over 25 years of research in the Atlantic Ocean to identify the garbage in the North Atlantic Subtropical Gyre.  More than 64,000 individual plastic pieces were collected at 6100 locations that were sampled yearly over the course of the study, and the results were published in the journal Science last year.  On my sail in 2006, I can remember our net tows every 12 hours, in which we lowered the giant net into the water alongside the ship for an hour, and hauled up the net to examine its contents.  My research was on the migrating patterns of conger eels, so in addition to collecting eel larvae, I also had to sort through lots of tiny plastic bits.  The lighter plastics, such as low density polyethylene (recycling number 4), float, whereas the heavier plastics, such as high density polyethylene (recycling number 2) sink.  This means that we don't see the heavier plastics that sink to the bottom of the ocean floor, while milk jugs, pen caps, wrappers, etc. float near the surface of the water.  So, where did these plastics come from, and what impact do they have on oceans?

Not surprisingly, a lot of this waste comes from land sources.  All of the litter on the ground that is washed downstream or directly into our harbors and rivers, is eventually carried out to sea.  The surface ocean currents determine where the debris accumulate, which happens to be in a high concentration a few hundred miles off the coast of Georgia, in this case.  Some may place the blame on barges and cruise ships, but international ocean dumping laws were created in 1988 to prevent dumping waste into the ocean.  Although I am sure that some of the garbage comes from unregulated ocean dumping, I am also sure that our land-based impact is the major contributor of plastics in the ocean.

These plastics are dangerous for ocean wildlife because they are subject to photodegradation.  Ultraviolet light degrades the plastics into extremely small particles.  These particles are mistaken for phytoplankton by marine animals (including birds) and ingested as food.  There are millions of sad stories about sick or deceased animals from eating or becoming entangled in plastic.  Oceanographer hero, Sylvia Earle, says that the fate our lives and the oceans are one; the ocean provides us with 85% of the atmosphere's oxygen.  If we do not take care of the oceans and the diverse life within them, we are ultimately harming mankind's longevity.  SEA, along with many other researchers, have shown that now is the time to re-think plastic production and disposal.  The ocean is not our garbage can.