From the microscopic to the gigantic, plastic debris has plagued our oceans since its invention. Much of the problem originated initially because we didn’t realize that plastics don’t degrade until after we had dumped tons into the ocean, largely off of ships as trash. WHOI offers a good summary of the history of plastic pollution. Many things changed since that first realization and the nature of plastics in the marine environment has a very different face nowadays.
The plastic is smaller and more widely distributed. There are fairly well-known areas that collect the plastics such as the Great Pacific Garbage Patch. There are also other areas affected that are closer to shore and where people use marine resources. Plastic often settles in seagrass beds that serve as important nursery habitat and on beaches where turtles and shorebirds mistake them for food and nesting material. Need more details on plastic?