At least, that’s what NASA scientists speculate.

Chemical analysis from the Phoenix lander indicates that the Martian soil is alkaline (slightly basic) with a pH between 8 and 9. Further, the soil released both water and carbon dioxide vapor when baked in an oven, indicating that it had once interacted with water at some level.

It’s interesting to speculate that with an influx of water and a slight thickening of the atmosphere that plant life, especially if adapted to harsh conditions, might thrive on Mars…or might be thriving there now in some unexplored crater.