Using data from Curiosity scientists have for the first time identified nitrates, also called fixed nitrogen, on the Martian surface.
There is no evidence to suggest that the fixed nitrogen molecules found by the team were created by life. The surface of Mars is inhospitable for known forms of life. Instead, the team thinks the nitrates are ancient, and likely came from non-biological processes like meteorite impacts and lightning in Mars’ distant past.
Features resembling dry riverbeds and the discovery of minerals that form only in the presence of liquid water suggest that Mars was more hospitable in the remote past. The Curiosity team has found evidence that other ingredients needed for life, such as liquid water and organic matter, were present on Mars at the Curiosity site in Gale Crater billions of years ago.
The data also suggests that these nitrates are widespread on the Martian surface.
The most important aspect of this discovery to me is not so much that it suggests the faint possibility of past life on Mars but that it makes Mars a more hospitable place for life in the future. Nitrates are essentially fertilizer, and for Mars to have this material in the soil already means it will be easier to figure out how to grow crops there.