London: Previous research has shown that marine microbes could beat plastic pollution.
Now, marine microbiologist Tracy Mincer of the Woods Hole Oceanographic Institution in Massachusetts and his colleagues have discovered that bacteria seem to be digesting the plastic garbage.
They examined bits of fishing line, a plastic bag and a pre-production plastic pellet fished out of the Sargasso Sea, an area of the North Atlantic where currents cause debris to accumulate.
Electron microscopy revealed bacteria-like cells living in the plastic, as if they were eating the surface away.
‘They look like you took a hot barbecue briquette and threw it into snow,” Nature quoted Mincer, as saying.
“You see this melting bit all around the outside of the cells, and they`re just burrowing into the plastic,” he added.
According to Mincer, though bacteria have been found digesting plastic in landfills, this is the first evidence of marine bacteria breaking down plastic in the ocean.
The new discovery might help explain why the amount of debris in the ocean has levelled off, despite continued pollution.
Researchers, however, don`t yet know whether the digestion produces harmless by-products, or whether it might introduce toxins into the food chain.
According to microbiologist Linda Amaral-Zettler of the Marine Biological Laboratory, Woods Hole, genetic analysis showed that the bacteria on the plastic differ from those in the surrounding seawater.
The DNA sequences obtained showed that almost 25 percent of the bacteria on one polyethylene surface were vibrios, bacteria from the same group as the cholera bacterium.
The researchers also found genetic and microscope evidence of eukaryotes — organisms with more complicated cells than bacteria — on the plastic.
The finding was presented at the 5th International Marine Debris Conference in Honolulu, Hawaii, held recently.