Re: Can food be grown in Mars? Possibly in a greenhouse on Mars

Hi Alex,

Scientists don't actually know the answer to your question at this point. There have been experiments where scientists grew plants in soils derived from meteorites (in other words, soils that have the same chemical composition as the meteorites), but the meteoritic soils they used weren't martian. They were from meteorites called chondrites, which do not come from Mars. No one has done the experiments using soils derived from martian meteorites. The difference between the martian meteorite and the chondritic meteorites used in the experiment is that the chondritic meteorites contain carbon, whereas the martian meteorites generally do not to any appreciable level.

We could probably grow plants on Mars, provided that we have a heated greenhouse and could irrigate the plants with liquid water. The atmosphere of Mars is high in carbon dioxide, so plants would have no trouble taking that in from the atmosphere. There isn't much nitrogen in the atmosphere, though, and the plants would definitely require an alternate source of that. On Earth, microbes that live in plant roots fix nitrogen from the atmosphere so that the nitrogen compounds are in a chemical form that the plants can use. That is, nitrogen in the atmosphere is either nitrous or nitric oxide (N2O or NO), and plants can only use nitrate (NO3-) or ammonium (NH4+, which is preferable). Presumably, the plants on Mars would require these microbes as well. As far as nutrients that are typically derived from rocks (such as phosphorus, sulfur, and trace elements such as molybdenum that play integral roles in plant biochemistry) are concerned, the martian surface seems to contain all of these in some form. The problem is that we don't know the mineralogy of the martian surface well enough to know whether the nutrients are accessible to biological organisms. We only know what the major iron minerals are, and the approximate abundance of major elements.

There are people who want to colonize Mars, and I'm sure they've thought extensively about growing food there. You might want to try the Mars Society website for more information (http:// marssociety.org/). The NASA Astrobiology website (http:// astrobiology.arc.nasa.gov/) might have relevant information as well.

Sarah Earley
CU Boulder