Six decades in the making the man-made ecosystem known as the plastisphere began as particles of degraded plastic no bigger than grains of salt.
When that debris washes into the ocean, it breaks down into bits that are colonized by microscopic organisms, many of them new to science. Researchers suspect that some of the denizens may be pathogens hitching long-distance rides on floating junk.
Scientists also fear that creatures in the plastisphere break down chunks of polyethylene and polypropylene so completely that dangerous chemicals are leached into the environment.