Styrofoam does not biodegrade at all. It degrades into smaller and smaller pieces over time, like rocks turning into sand, and finds its way into the food chain, where it begins to poison animals that eat it in error. There exists no bacterium currently capable of metabolising styrofoam or plastics, and it may be hundreds of thousands of years before one evolves. By which time, the planet will be choked with plastic and styrofoam.
Beware of plastics that advertise themselves as degradable. There are various kinds of bin liners, sandwich bags and freezer bags on the market and indeed they are just that. Merely degradable. All that means is that they break down into smaller pieces of plastic quicker than regular plastic, meaning that they poison smaller creatures more quickly than non-degradable plastics do. And when the plankton dies, we're all screwed.
Beware of plastics that advertise themselves as degradable. There are various kinds of bin liners, sandwich bags and freezer bags on the market and indeed they are just that. Merely degradable. All that means is that they break down into smaller pieces of plastic quicker than regular plastic, meaning that they poison smaller creatures more quickly than non-degradable plastics do. And when the plankton dies, we're all screwed.