The biomass of archaea outweighs all other life on Earth. 
The deeper you go, the more of them you find. 
What could it be that they are doing down there? Hmmmm? 
  
How come you find oil in granite, and in other weird places, if you drill deep enough? 
How come old oil wells are slowly refilling? 
  
I pretty much think Thomas Gold and the Russians have it backwards, except with respect to methane. I don't think those little archaea (Delicate Arch-aea? ) are eating abiotic oil. I think they are MAKING biotic oil from rocks and methane. And why not breed them specifically to do this?