Photo: Ralph Hockens/Flickr
Plastic is now the foremost form of marine pollution—perhaps not surprising to readers considering the publicity that the great Pacific garbage patch has received, as well as its counterpart pollution patches in the world's other oceans, and even the Great Lakes. It's a bad thing, on many levels, with the detrimental effect on marine animals well documented. The effect of all that plastic on the smallest residents in the ecosystem of the open ocean has heretofore not been one of these.
Now, researchers have attempted to remedy that knowledge gap. Writing in Environment Science & Technology, they've dubbed these areas of floating plastic debris the "Plastisphere" as it's a distinct enough community from the surrounding areas.
What this latest work does is look at the effect of that plastic on microbial communities in the ocean. Using plastic collected from several locations in the North Atlantic, analyzed with a scanning electron microscope, they found that there are several types of bacteria present that may help break down the plastic.
There also is a stable environment for microbes that potentially can cause illness though—bacteria from the genus Vibrio. Some of these bacteria can make invertebrates, fish, as well as humans sick, or even kill them. Depending on the species of Vibrio, gastroenteritis can result, as well as infection of open wounds leading to septicemia. Cholera is also caused by a strain of this bacteria.
The North Atlantic garbage patch was first documented over 40 years ago. Estimated to be hundreds of kilometers across, with a density of over 200,000 pieces of plastic per square kilometer, it can shift in location by up to 1,600 kilometers seasonally.
About 80 percent of the Plastisphere is comprised of materials disposed of on shore, that in one way or another make it into the water. The remaining 20 percent coming from litter dumped from ships, discarded fishing gear, materials washed off boats. Of the material coming from shore, plastic bags, food containers, and product packaging form the bulk of the debris larger than 5mm in size.
In the decade from 1997-2007 there was a 500 percent increase in plastic debris making its way into the Central Pacific Gyre. Off Japan, from the 1970s to 1980s the amount of plastic in the water increased by a factor of 10, increasing that much every two-to-three years in the 1990s.
That the problem is only getting worse shouldn't be surprising considering that in the first decade of the 21st century more plastic was manufactured than in the entire history of plastic production.