There was a sci fi novel I read as a teenager The Lord's Pink Ocean by David Harry Walker. It describes a Post Apocalyptic earth after scientists dumped a bunch of bacteria specially designed to eat all the pollutants in the oceans. It was a bright pink color and *surprise!* it didn't stop with just the pollutants, it ate everything in the ocean, and then managed to evolve to live on land as well ( I think- this was a long time ago), where *surprise!* it ate everything there. The story was about a couple of families who, through a lucky chance, lived in exactly the right spot that the bacteria couldn't get to because their little valley was protected by bare rocky cliffs that prevented the bacteria from crossing over to eat the last little bit of life on the planet. Even though there was a lot of holes in the premise, I've never forgotten the message from that book.