Funnily enough, the microbial communities that can digest oil spills (given the right set of conditions) attract a lot of attention after each major disaster, but suffer from neglect soon after. I covered this issue briefly in my book Life on the Edge (1998) and have now revisited it on the occasion of the Deepwater Horizon spill.
Turns out the research hasn't made as much progress as one might have wished, it's still mainly guesswork if you want to predict whether a given spill will or will not be efficiently degraded by microbes.
I wrote a news feature about all this for Chemistry & Industry, which is out today:
Digesting a sticky problem
Chemistry & Industry No. 23, page 14-15.
Full text (open access)