Shorebirds looking at human trash on a beach
Engineered microbes could help dispose of human trash in our oceans. Photo: ©Tony Neilson

Beware the ‘cane toad solution’

Just when I thought the world really was going to hell in a handcart, there is a tiny new glimmer of hope.

Tiny, because the object of this optimism is probably no bigger than the microorganisms on my skin that make me irresistible … to mosquitoes, and other biting insects. (No matter how often we wash, we all carry microbes on our bodies. But some are apparently more appealing to blood-suckers than others.)

But I digress. The reason for this quiet elation is a very recent discovery that microscopic marine microbes are eating away at the scourge or our oceans – plastic!

Continent-size clumps

According to Sustainable Footprint, nearly 70% of all ocean litter is plastic, and it floats in huge clumps, some bigger than continents. Most ends up in central regions where slow-moving circular currents congregate the debris into a constantly moving mass of plastic.

Over time (hundreds of years), the plastic slowly breaks down into ‘dust’ that small marine wildlife mistake for plankton. The little fish will in turn will be eaten by larger fish, and so the cycle of untimely death by plastic continues. (It is estimated that there are six kilos of plastic in the world’s oceans for every kilo of naturally occurring plankton.)

Concentrations are stable

However, there is better news. Ocean pollution researchers have found that despite a fourfold increase in plastic production, the main concentrations haven’t grown in 22 years.

How so? Microbes. Plastic-eating bacteria were first discovered in landfill a decade ago by Canadian high school student Daniel Burd. He collected soil samples from landfills and started feeding the soil bacteria a diet of ground up polythene bags. He found that a combination of Sphingomonas and Pseudomonas bacterial types could completely degrade a polythene bag in three months.

Frigate birds scavenging foo off the ocean
These frigate birds are scavenging scraps from a passing vessel. It could just as easily be plastic. Photo: ©Tony Neilson

Promising results

A recent five-month study where weathered and brittle plastic collected on the Greek coast was immersed in salt water containing certain natural and engineered microbes enhanced with carbon-eating strains produced promising results.

The pieces were either polyethylene or polystyrene, and both types lost significant weight after exposure to the microbial concoction.

Using marine microbes to eat up the ocean trash is apparently a definite prospect. But, is the plastic-munching bug green or mean?

Hopefully science will prove that beyond all reasonable doubt before it unleashes a ‘cane toad solution’ on our oceans.

(Footnote: Unrestricted ‘progress’ in human development over the past 50 years is the main reason a million species on our planet are currently at risk of extinction. So says the UN Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.

Natural Images 2019


©2018 TONY NEILSON All Rights Reserved. All images are protected by Australian copyright law and cannot be downloaded or reproduced without my permission. Please contact me.


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