A new microbial community is thriving, living off plastic debris in the depths and the surface of the oceans. The plastisphere is a parallel biome rivaling the newly-built environment spawned off the millions of tons of plastic that has ended up in the oceans. Human debris now outnumbers and outweigh marine debris and has been colonialized by microbial and various other forms of microscopic life.
The biggest offender among various forms of plastics lurking in the waters is plastic bottles, an estimated 1 million of them crashing onto the seafloor every minute. And Pet bottles (polyethylene terephthalate) dominate the numbers.
Scientists found a couple of bacteria that are capable of breaking down the pet bottles. Thioclava sp. BHET1 and Bacillus sp. BHET2 were the two plastic-eating bacteria found in the depths of the ocean but were isolated in the laboratory.
The plastisphere is a definite region, much like the hydrosphere, the magnetosphere, or the atmosphere. But it’s a man-made marine environment that happens to be ‘plasticized.’ The ‘garbage patch’ spread out in the Pacific Ocean is the biggest concentration of plastic waste which is approximately double the area of France. Though the dumps in other oceans are just as big.
The term, plastisphere, was first used in 2013 and referred to a combined mass of plastic-colonizing living organisms. It included fungi and bacteria, though the definition has since been expanded and involves larger organisms, even jellyfish and crabs that have transformed to live within plastic waste floating in the oceans.
Marine microbiologist Linda Amaral-Zettler of the Royal Netherlands Institute of Sea Research coined the term. She says that back in 2010 when she and her team were on a cruise to isolate and identify organisms that adhere to or depend on plastic, she came up with this convenient name to describe this unique community that had come up with the introduction of the vast amount of plastic waste in the oceans.
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The Plastisphere has existed from the time plastic had begun to accumulate in the oceans. And it is only now that we have discovered that it is a new ecosystem that is as complex and vast as any other ecosystem. The only difference is that it is man-made.
Plastisphere As Complex A Biosphere As Any Other
There are organisms thriving within the plastisphere that photosynthesize, and then there exist organisms that are prey and predators, parasites and symbionts, and other complex organisms that are common to other ecosystems. But while other ecosystems have developed over years, the plastisphere has come up within the last century.
While the basis of this living environment is artificial, the organisms inhabiting and colonizing them are natural. And it is spread over the continent based on something persistent and durable. And a unique discovery is that the colors of plastic influence the organisms that thrive in it. Blue plastic allows for a richer and diverse community of organisms than transparent or yellow plastics.
New Forms Of Bacteria In Plastisphere A Cause Of Concern
Newer forms of bacteria have been discovered in this biosphere. Vibrio contains several pathogens, with some of them that can cause gastroenteritis. But it is the presence of plastic itself that concerns scientists. And they attract iron, carbon, phosphorus, and nitrogen. These in turn bring in microbes.
Scientists are studying these organisms from two angles. One is the potential of a number of microbes to decompose and disintegrate hydrocarbons. The other is the presence of pathogens in the plastisphere.
One exciting prospect of studying the plastisphere is discovering bacteria that would be capable of breaking down plastic waste. Scientists believe that this is going to be a frontier of research in discovering ways to fight plastic accumulation on land and in the oceans.
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Understanding the plastisphere is going to be crucial as we have changed our planet in a way that has led to the evolution of new microbes that are here to stay.