Chlorine photosynthesis on exoplanets

[stevebowers.]

You can't have chlorine photosynthesis without light. If a chlorine atmosphere is really that opaque, the only way to make it work would be to have skyplankton at the top of the atmosphere column.

[stevebowers.]

I've just read (skimmed through) the Haas paper; it says that the liberation of 1% of a bar of Cl in the atmosphere would require 10x the salt in the Earth's ocean.

I see a coincidence here- if we liberated all the chlorine in the ocean into the atmosphere, we'd get just the right amount to allow some light through. 0.1% of a bar of Cl would be thin enough to allow enough light for photosynthesis, and would be a realistic quantity of chlorine for an Earth-like world.

[Matterplay1]

I've just read (skimmed through) the Haas paper; it says that the liberation of 1% of a bar of Cl in the atmosphere would require 10x the salt in the Earth's ocean.

I see a coincidence here- if we liberated all the chlorine in the ocean into the atmosphere, we'd get just the right amount to allow some light through. 0.1% of a bar of Cl would be thin enough to allow enough light for photosynthesis, and would be a realistic quantity of chlorine for an Earth-like world.

So, the lesson of all this seems to be that we can still have our greenish air and so on if we ratchet back the amount of free chlorine to something much less. Chlorine is so colourful that it will do the job in much smaller quantities than those I wrote about. I'll find time to read the articles myself, first, just to be sure, but it looks like I'll be tweaking the stats on OA's chlorine worlds to match expert opinion.