[mlyle]

> Actually you can't break down plastic at all. You can just grind it with your teeth.

I said most plastics. Some plastics have a ton of starch bonds or are vulnerable to HCl, and can be broken down by mammalian digestive tracts. I have good enzymes to break starch bonds, and I have HCl in my stomach, so I can digest e.g. TPS to a great extent or PLA to a lesser extent.

> This is where your mistake lies - if you can degrade plastic at all, then you can degrade it all the way to water and CO2. There is no partial degrading here, you either can, or you can't.

I think you're not understanding me. One species of bacteria beginning to digest plastic all the way to water and CO2 doesn't instantly remove all the plastic floating in the ocean, let alone removing it from the marine food web where it has accumulated. It doesn't even guarantee the amount of plastic in the ocean goes down: it's easy to imagine situations where the rate at which bacteria remove plastic from the oceans is lower than the rate than it is introduced.

Therefore, even after some bacteria begin to break down some plastic, plastic can still accumulate in other organisms in the ocean. The long term prognosis is greatly improved, but things are not guaranteed to improve much at all in the near to intermediate term.