a team of international scientists illustrate how they created—by accident—a new enzyme capable of breaking down plastic bottles.
So let's assume microbe like that was engineered to just eat plastic like it eats sugars and other stuff. Then, containment broke in processing plants next to ten rivers that contribute the most to plastic problems:
How fast can we get this microbes all around the oceans, especially plastic deposits? They will be almost unchallenged on food, because hardly anything else in nature eats plastic, so all real life models look irrelevant to me. On the other hand, I'm not sure if I can just use speed of ocean currents - and if I can, simulating it is above my knowledge at the moment.
You can give this microbe any advantage needed, I want it everywhere as fast as possible to make my apocalypse sudden, and to make world unable to stop it.
Note: This question does not touch things that are not relevant to rapidity of spreading. It avoids them on purpose, they will be worked upon in parts 2, 3 and possibly more. Now, if there is something missing about how fast could it spread in oceans, I'll be glad to work on this question. If it belongs to follow ups, please wait.