Well this certainly makes sense. If organisms can thrive on phosphorus, the element above arsenic, then it makes sense to have them thrive also on arsenic. Since they are in the same column, they have similar chemical properties. I know arsenic is poison to humans, but the whole "phosphorus as a later evolution" type of thing definitely fixes that issue. Hmmm what next? Oil producing bacteria? (yay the end of the oil crisis!)

