Mars, being smaller, would have cooled much sooner than Earth allowing liquid water to ineract with the environment. I would guess that a, possibly common, large impact hit a water area, escape velocity might be reached.
Originally Posted by TriangleMan
As for survivability, bacteria was found on a lunar camera lens after two years of moon time (according to my Bill Bryson cd).
It would be interesting to see ejection profiles for land and sea impacts.
We know time flies, we just can't see its wings.