Comment Re:One non-disturbing theory (Score 1) 304
The term plastic covers many materials. The ones made from hydrocarbons - polyethylene, polypropylene etc are gradually attacked by bacteria. If they are very thin as in plastic bags they are short lived. it is a little lighter than water, so it floats and gets the cross links broken by UV light unless filled with something heacvy, clay, TiO2 etc and might sink.
These are not long lived, nor are they hard, the scraping tongues with erode them, and a few cyles = gone.
If you replace one or more Hydrogen with fluorine or chlorine you get items that are not metabolized by any complex organism, however bacteris can colonize them and they remove an atom at a time, so they eventually go away.
https://www.google.ca/?gfe_rd=...
These are all soft so the scraping of tiny teeth turns them into small particles and the bacteria get at them.
One big problem with small particles is their lack of nutrition, so the small animal wastes energy to gnaw it and gets nothing back. Too many small particles and they starve to death via metabolic losses. People can starve on some foods that take more energy to digest then they yield.
Recently microspheres for cosmetics have been released into the water and they get through filtration plants = starvation again for the small fly if there are too many.
The rise of biodegradable layers has helps plastic go away sooner, if we made bags from starch film, if would be eaten in weeks in the sea