Researchers are finding that ocean currents carry plastic pollution -- cigarette lighters, plastic bags and other trash -- from the world's coastlines to the middle of its oceans. Two experts answer your questions on the impact of plastic ocean pollution.
Are the plastic particles in the ocean concentrated at relatively shallow depths? Also, if we could reduce the amount of plastic entering our oceans, could the ecosystem "absorb" the current concentration, or is it too late to save our oceans?
Holly Bamford responds:
Plastic debris, like many other types of marine debris, has no boundaries and is carried by wind and currents far from its origin. Marine debris is found in waters of varying depths, from nearshore shallow waters to the middle of an ocean. As far as at what depth can plastic particles be found, we believe that some (not all) of the plastic particulate debris can be found in the upper layer of the ocean. Remember that 1) not all plastics float and 2) biofouling (biological growth) occurs on debris at sea, adding to the weight of an item.
For your second question, research has shown thus far, plastics degrade very slowly, mainly via sunlight (photodegradation), into smaller and smaller pieces. Exactly how long it would take for plastic to be reduced to its inorganic components is not known. This being said, it would most likely take a very long time for plastic debris to leave the ecosystem on its own.
This is where people can help. Reduce, reuse, and recycle, and get involved in local debris cleanups. While there are a myriad of problems facing our oceans today, including marine debris, you should not let that stop you from having hope and enacting a change.
Charles Moore responds:
The majority of the particles are within 10 meters of the surface in calm conditions, but get mixed more deeply when it is rough. We have found plastic in all our trawls down to 50 meters. The ocean will eventually "spit out" or cover the plastic debris if we stop putting it in.