Celestia Forums

I'd like to people's opinions on this subject. Given Mars' atmosphere, if there were plants and water on Mars, would photosynthesis be more efficient? What would be the materials used to decide this?? Looking forward to hearing your thoughts!

(I'm assuming you've got your putative plants in a room temperature greenhouse with warmed up martian atmosphere circulating through it - otherwise your plants are going to freeze instantly )

I don't think it'd really be more efficient without changing the plants themselves. Plants can only take in a certain amount of CO2 per instance of the reaction that creates sugar and oxygen:

6H2O + 6CO2 ----------> C6H12O6+ 6O2

Having a CO2 atmosphere just means that there's more CO2 available to convert, I'm not sure it means that it'd be converted more efficiently though.

However, the obvious problem is that sunlight provides the energy for the reaction, and the sun is about 0.4 times the brightness at Mars as it is at Earth (so even if you were at the equator, you'd be getting less than half the illumination per square metre that you'd be getting at Earth's equator). That alone might make the photosynthetic reaction that much less efficient, depending on how much energy is actually required for the reaction to occur.

The fact that there are fewer clouds on Mars compensates for the lower light levels to a small degree,

but not enough to make photosynthesis as potentially effective as on Earth.

What would be a good experiment to perform to find out about the effeciency of photosynthesis on Mars compared to Earth??? Materials used??

For your experiment, use a vacuum pump to remove air from the
terrarium. Put in CO2 at a pressure of 7.6 torr (1/100 atmosphere).
Get an x-ray source to radiate the terrarium with x-rays. Add water.
Put on lead apron, lead face mask, lead gloves. Sit back and watch
everything die in the terrarium. Use time lapse photography to record
the motion of the plants as they wilt. Show the video here.

One other factor you must take into account is that plants also need Oxygen to survive. Simply sticking them in a near 100% CO2 atmosphere isn't going to give you very good results. Just thought I would drop that in.

Don. Edwards

less, for obvious reasons (the 1st is we are here and not there).

to add I would say sun light being just right & planet size/gravity being just right, would be a factor for the advanced development of surface life.
However when we refer to life on mars we are NOT refering to what we would call life here on earth....

what may have developed on Mars may be no more complex than sub surface autophids....tiny microscopic bugs that livein dark(?), warm, possibly wet or dry-icey places.