terraforming a nitrogen world

[tniemi]

Okay. What should I take in account when terraforming a world with a nitrogen dioxide atmosphere?

The nitrogen dioxide reacts with the sea water and creates both nitric acid and nitric oxide. (Ostwald process) So we probably have nitric acid seas.

Nitrous oxide is a greenhouse gas, but nitrous dioxide can block sunlight. Is there a greenhouse effect in effect or not? I do not know. There is probably a portion of (<5%) carbon dioxide in the atmosphere too.

Now let's start the terraforming and plant something in the deep seas. Something like phosphorus-nitrogen (P-N) plants that absorb the nitric acid, recudes it and relases the oxygen as a waste product. Some of the released oxygen will merge with the nitric oxide from the Ostwald process but the oxygen levels will eventually win this battle. Tons and tons of nitrogen will be absorbed by these strange plants. (Where does the phosphorus come from? From deep sea deposits of apatite? Or from somewhere else?)

Eventually the atmosphere will clear up, PH of the seas lower and the first acid free rains come. Now it's time to get the carbon cycle running...

The final world should be equpped with human-ideal pressure and temperature.

What was the starting world like?
Is there something goofy in this general picture?
Any ideas? Visions? What could go wrong? What is still needed?

The P-N plants are a bit sci-fi but those start to be a quite standard subjects in xenobiology:
http://members.lycos.co.uk/thepixie/sfrpg/xenochem.htm

TIA! Any info would be helpful...
--
Tero

[kikinho]

Interesting!

I agree that this type of world could harbor complex life. Another interesting biosphere is a biosphere based on fluorine. Life there is silicon-oxigen based, and beings breathe fluorine. The solvent is HF. They live in temperatures about -30??C and -50??C. I've read about this in some site that I don't remember now.

[Evil Dr Ganymede]

Fluorine worlds would have to be artifical - they are VERY unlikely to form naturally - Fluorine is too rare an element and too reactive to be stable in a planetary environment, unless something was actively producing it, and even then it would be a contaminant in an atmosphere that is mostly another gas.

A NO2 world would probably be unlikely, you'd have to have to have a high N2:O2 ratio initially for it to react with to form nitrates and nitric acid. I guess you'd have to get the O2 from photodissociation of water on the surface, or something. Either way, it'd probably be like Venus - NO2 etc are not pleasant compounds (they're a major component of smog on earth). With the nitric acid in the envirnoment too, there'd be major chemical weathering.

The N2 and O2 on Earth don't react to get replaced by nitrogen compounds because we have denitrfiying bacteria to break down those compounds and produce more N2.

[Rocket Man]

tniemi said:

Nitrous oxide is a greenhouse gas, but nitrous dioxide can block sunlight. Is there a greenhouse effect in effect or not? I do not know. There is probably a portion of (<5%) carbon dioxide in the atmosphere too

The clouds would just help double the tempture of the surface. Take Venus, Venus has Carbon Dioxide atmosphere and a thick cloud cover.

To terraform, It going be a hassle getting rid of the greenhouse. Plus the the surface would be just like Venus. So you have a venusian planet.

This planet isn't a good canidate for terraforming.

[eburacum45]

Oh, I don't know; if you have a planet with a strong greenhouse effect, shade it from the local star using a sunshade at the L1 point.
Then use denitrifying bacteria to convert the NOx into nitrogen gas and oxygen;
when the planet has a suitable temperature you can remove the shade. All those weathered rocks will need processing before they are suitable for Earth-type plants- but there should be plenty of nitrate for fertiliser...

alternately why not try encouraging the development of the phosphorous/nitrogen ecology and turn the planet into a reserve, while living in orbiting habitats nearby?
As an experiment it could have some interesting results.

[Rocket Man]

Who said that life has to be made from carbon? Maybe a new spieces of alien organisms and evolve grow here maybe surviving the harsh condotions. They might even terraform it by themselfs?