What common chemical/physical reactions would, in an atmosphere composed of ~20% Oxygen and ~80% Argon, behave differently than on Earth?

I think plants would get into trouble. Plants need nitrogen compounds, which many of them get from bacteria that take the nitrogen from the air. Without nitrogen in the air, those bacteria cannot create nitrogen compounds, and thus those plants are in trouble.

Note that the nitrogen compounds in dung indirectly come from plants, too. So that's no way to get new nitrogen into the cycle. Ultimately all that nitrogen comes from the air.

And the nitrogen in artificial fertilizer is taken from the air as well, so unless there's another source available, even that won't work.

Note that Argon, as a noble gas, cannot replace nitrogen in chemical compounds.

posted almost 9 years ago

celtschk‭

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Argon is inert, meaning that in doesn't really interact much with anything. Like the other noble gases, it is much less reactive than the major components of the atmosphere. Therefore, to look at changes in this atmosphere, it's important to look at what we'd lose if the nitrogen was this substantially reduced.

That said, atmospheric nitrogen (N₂) doesn't do much, either - it's also quite inert. So indirect results are what we need to look at - specifically, the nitrogen cycle.

Things that are impacted by the nitrogen cycle:

• No nitrogen fixation, leading to a lack of ammonia produced by nitrogen-fixing bacteria.
• Highly reduced amino acid synthesis (it needs that ammonia)

Really, atmospheric nitrogen isn't that important. Other sources of nitrogen exist, and organisms get quite a lot of their nitrogen from the ground and elsewhere.

posted almost 9 years ago

HDE 226868‭

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