Among the most common flotsam to wash up on our beach here in the Bahamas are plastic milk crates. Modular shelving, I call them. Turned on their sides and stacked against the garage wall, they make a great storage system.
Given the number I have collected, there must be tens of thousands of crates floating around out there. They are a wonderfully versatile invention. Fishermen use them to store their gear or their catch, sailors to store food and equipment. Many apparently get tossed or fall overboard.
Milk crates are the tip of the plastic iceberg. In the North Pacific subtropical gyre -- a Texas-sized high pressure system where circulating currents round up floating debris -- it has been estimated that there are 6 pounds of floating plastic for every pound of organic life. Plastic degrades slowly at sea. Birds, seals, fish ingest the stuff. Even plankton are at risk.
It is sometimes said that we are drowning in a sea of plastic. It turns out that "sea of plastic" is more than a metaphor.