The linkage between these findings about Meridiani and the MARSIS results were not lost on me either - I'd be interested in hearing what others have to say. I think these two most recent papers makes life on Mars less likely. I also think they support a "cold and sometimes saturated" model of Martian geophysical history, punctuated by an occasional castrophy induced deluge.

I think one of our problems with understanding Mars is that it looks too much like the deserts of the American southwest. That lulls people into thinking it shares a similar environment when, in fact, the geochemistry of Mars not exactly friendly with the biochemistry of life. Its actually a very poisonous place.