08 November 2011

Ocean Bacteria Might Help Clean the Oceans from Plastic



We may not see them but the results of our throw-away culture are killing the oceans' inhabitants. Enormous patches of plastic trash lure ocean animals into mistakenly taking it for food. Albatrosses fly tens of miles to feed their young with colorful plastic debris, sea lions wear necklaces of plastic bags and sea turtles grow with mutated shells because of plastic rings that once got stuck around their bodies.

Over a million seabirds, and more than 100 thousand marine mammals die every year from ingesting plastic debris. Some researchers estimate that there are over 13 pounds (6 kg) of plastic for every 2 pounds (1 kg) of plankton in the Pacific Garbage Patch.

Photo: Tom Magliery
The history of plastic
The first synthetic plastic material, parkesine, was patented by Alexander Parkes, in UK in 1856. But the development of plastics has gone a long way - from the use of natural plastic materials (chewing gum, shellac) to chemically modified natural materials (rubber, nitrocellulose, collagen, galalite) and finally to completely synthetic molecules (bakelite, epoxy, polyvinyl chloride).

The first plastic based on a synthetic polymer was made from phenol and formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo Hendrik Baekeland, a Belgian-born American living in New York.

Since the 1950s, one billion tons of plastic have been discarded and may persist for hundreds or even thousands of years. A great percentage of the discarded plastic that is not in landfills finds its way into the oceans either blown by the wind or floating on the rivers from regions that are thousands of miles far from the sea. Plastic comprises 80% of the trash floating in the oceans. The weight of just one of the great garbage patches,  the so-called Great Pacific Garbage Patch, floating between Hawaii and California has been estimated to about 4 million tons.

Photo of Salmonella typhimurium invading human cells by: Rocky Mountain Laboratories, NIAID, NIH through Mycrobe World

Plastic eating bacteria in the oceans
But maybe there is light in the tunnel. Scientists working on environmental pollution have noted that although global plastic production has grown fourfold in the last 20 years, the quantity of trash in the oceans has remained the same. An ocean bacteria may be eating the plastic but the consequences of that are yet to be researched. It s not yet clear if plastic digestion produces harmless by-products, or whether it might introduce toxins into the food chain.

Tracy Mincer, a marine microbiologist in the Woods Hole Oceanographic Institution in Massachusetts says:
“It has been proven that microbes can degrade plastic. What's significant is that the plastic is being degraded in a nutrient-poor area of the sea, an "ocean desert." We are seeing the plastic particles as a type of artificial reef that certain types of microbes can colonize. Since plastic has a much longer residence time in the water column than any other natural particle in the water column, this could be making a significant impact."
The bacteria was found in a region of the North Atlantic Ocean called the Sargasso Sea. It is  breaking down the plastic, but it is yet to be researched if the byproduct is environmentally-friendly waste or a toxin.

The great garbage patches found in the regions of the five ocean gyres that have been considered by scientists devoid of life may turn out to be full of unknown living communities. They are now seen as an artificial reef that certain types of microbes can colonize.

But the discovery of the plastic-eating bacteria poises further questions about the effect on other aquatic life. Scientists are yet unsure of the way the byproducts will influence the overall microbial balance of the ocean. The part of the Sargasso Sea where the bacteria is found is quite poor in nutrients and depleted of phosphorous, challenging scientists to find out if it is “stealing away” phosphorous from others that normally receive this share.

New bacterial species
It has already been proven that the bacteria on plastic are different than the ones in nearby seaweed or in the surrounding water. The DNA analysis by the Marine Biological Laboratory, Woods Hole so far shows that almost 25% of the bacteria on one polyethylene surface are vibrios - bacteria from the same group as the cholera bacterium. Evidence of eukaryotes, which are organisms with more complicated cells than bacteria have also been found on the plastic. With our collective strive for a fast-paced, disposable civilization we have obviously created a new world without even realizing there might be consequences but now they are a fact and we will have to find a way to deal with them, for better or worse.

How can YOU change the situation?
Humans have been playing with plastics for the past 60 years and it is no wonder that nature is looking for ways to adapt. If no organisms exist to decompose them, it is estimated that plastic bags and bottles will last for at least 400 years. Even after that period, the small bits of plastic may remain.

With or without plastic-eating bacteria, plastic still is a major problem for humanity.  Here are several things you can do to lessen the use of plastic in the world and give your grandchildren a chance:
  • avoid food packed in plastic
  • avoid disposable plastic dishes and cutlery
  • refuse plastic bags 
  • look for bio-degradable plastic products
  • place your trash in a closed bin
  • take care that your plastic is being recycled.