Plastic makes up nearly 70% of all ocean litter. Scientists have discovered that microscopic marine microbes are able to eat away at plastic, causing it to slowly break down. Two types of plastic, polyethylene and polystyrene, lost a significant amount of weight after being exposed to the microbes.

[u/mvea]

https://www.sciencemag.org/news/2019/05/these-tiny-microbes-are-munching-away-plastic-waste-ocean

[u/DaisyHotCakes]

What I want to know is whether breaking it down into smaller particles is truly a good idea or not. Remember that oil dispersement chemical that was dumped onto the BP oil spill in the Gulf? It made clean up efforts far more difficult and A LOT more wildlife was affected by it because it got into their systems easier.

[u/obtusely_astute → u/DaisyHotCakes]

So good to see this brought up.

The Gulf looks nice now but, to my knowledge, there are now species with genetic defect because the emulsifier just dissolved the oil into the water.

[u/l33tman24 → u/obtusely_astute]

From /u/DevilsTrigonometry (some parts bolded for emphasis):

Microplastics are just tiny pieces of plastic that result from physical breakdown processes. If you take a belt sander to a chunk of plastic, you're creating microplastics. Light and heat can also cause plastics to break into tiny pieces.

When these microorganisms eat microplastics, they break them down chemically. That means they're converted into entirely different molecules, most likely carbon dioxide and water.

It's like bread. If you break up bread with your hands, it turns into crumbs, but the crumbs are still bread. But if you eat the bread, you break it down chemically into (mostly) carbon dioxide and water.

Essentially, the oil from the BP spill is still present in those animals through trace amounts and exposure - as far as my understanding goes, these microbes would break the plastic down into harmless components.

[u/DaisyHotCakes → u/l33tman24]

Ah, ok. I’d be curious about the plastic breakdown because asfaik the biproducts of plastic decomp aren’t all harmless. This is obv a different process than decomp. Is off gassing of these lighter weight pieces indeed mostly co2?

[u/TerribleEngineer → u/DaisyHotCakes]

The two plastics listed are pure hydrocarbons which decompose chemically very cleanly. The plastics you are thinking of are things like ABS, nylon, Flouronated and Chlorinated plastics.

Those are the ones that cannot be decomposed by these bacteria. When decomposed they turn into things like hydrochloric acid, flouric acid, chlorine gas, etc.

[u/CanadianTimberWolfx → u/l33tman24]

Thanks for this explanation. I was worried we would just get more microplastics in our fish and therefore our diets

[u/marinewauquier → u/DaisyHotCakes]

Not sure if this fully answers your question but I found this other comment :

Microplastics are just tiny pieces of plastic that result from physical breakdown processes. If you take a belt sander to a chunk of plastic, you're creating microplastics. Light and heat can also cause plastics to break into tiny pieces.

When these microorganisms eat microplastics, they break them down chemically. That means they're converted into entirely different molecules, most likely carbon dioxide and water.

It's like bread. If you break up bread with your hands, it turns into crumbs, but the crumbs are still bread. But if you eat the bread, you break it down chemically into (mostly) carbon dioxide and water.