"Ammonia on Mars could mean life

By Dr David Whitehouse 
BBC News Online science editor 
 
Is there life beneath the soil? 
Ammonia may have been found in Mars' atmosphere which some scientists say
could indicate life on the Red Planet. 

Researchers say its spectral signature has been tentatively detected by
sensors on board the European Space Agency's orbiting Mars Express craft. 

Ammonia survives for only a short time in the Martian atmosphere so it must
be getting constantly replenished. 

There are two possible sources: either active volcanoes, none of which have
been found yet on Mars, or microbes."

http://news.bbc.co.uk/1/hi/sci/tech/3896335.stm