It's fairly well-known that certain bacteria that grow on dead/dying crustaceans can cause luinescence.
I purchased a fairly large number of "feeder" ghost shrimp (P. paludosus, from the look of them), expecting a high mortality. Well, I GOT a high mortality. Luckily, it seems to have leveled off. But last night, after I turned out my lights, I noticed what appeared to be a light in the shrimp tank. A recently dead shrimp (less than three hours, probably less than 2) was glowing a greenish-white. I was surprised how bright it was. I'v heard about this, but I'd never seen it before. Just thought I'd share.
I'm not saying it lit up the room but it was visible in a dark room from a few feet away. It was abbout as bright as one of those "glow-in-the-dark" toys.
I would assume others did as well, but no more died that night. Which is good, but leaves my curiosity unsatisfied.
So this forum has seen this phenomenon before. Don't know if it answers any of your quetsions, but Gregor does a good job of describing the organism responsible.
When I was diving in Australia on the Great Barrier Reef, there were bioluminescent dinoflagellate algae in the water. They glowed in response to movement, such that if you waved your arms or kicked in the water they lit up. I saw on some nature documentary that it is an indirect survival strategy for the algae. Once their predators (such as shrimp) eat them they start to glow. This is especially useful in animals with a see-through body such as ghost or other glass shrimp. This then makes the shrimp an easier target for its own predators. In the film, it was a squid. This benefits the algae because if more second-degree predators (shrimp-eaters) are attracted to the area, they will remove more shrimp and thus allow more algae to escape and survive. At least that was the explanation given in the documentary.