I'm piecing together the biology and ecosystem of a Titan-like cryoplanet. And I want it to have clear or nearly-clear skies instead of Titan's complex hydrocarbon haze, so that my ethane-based lifeforms can use visible light for photosynthesis.
Some planetary info:
- Magnetic field about two thirds the strength of Earth's.
- 120-150 kPa surface pressure.
- Atmospheric composition:
- 90-95% Nitrogen.
- 5-10% Methane or Hydrogen, or a mix.
- 1-4% Ethane (due to evaporation from lakes, seas and oceans).
- Trace amounts (< 1%) of oxygen or some other oxidizing gas or liquid. Emitted by plants as a waste-product.
What compounds could form either naturally or biologically that could function as a transparent UV-absorbing layer? I.e. an ozone layer equivalent.
Is less than 1% oxygen or other oxidizing gas (at 120-150 kPa) sufficient to form an ozone layer able to absorb 90-99% of UV-C and UV-B light? Or are greater percentages of oxygen required?
Could methane naturally react to form transparent UV-C and UV-B absorbing compounds that would be in sufficient concentration to act as an ozone-layer equivalent?