Interesting report here on the probable existence of bacterial life in the basalt rock layer of the ocean floor. These organisms would be chemotrophs living on chemistry rather than sunlight. To be most accurate the critters haven’t actually been found down there, but evidence of their activity and traces of DNA suggest it to be true.
Now pair this with the Mars Rover’s recent finding, and you’ve really got something! I say, terraform Mars first, ask questions later. Earth will be long gone before we can make Mars habitable, best to get started now!