I'm building a world for an artistic project, and I'm struggling a bit with how the photosynthetic organisms would likely be different from Earth's plants. I'm not looking for wild idea generation, merely the plausible differences you might expect (i.e. predict) based on the much different environmental parameters.
- M-Dwarf Planet (3310K star)
- Eccentric orbit combined with tidal resonance leads to zones on the planet which experience differing amounts of daylight per orbit. There is a "long day" zone in one hemisphere and a "long night" zone in the hemisphere opposite the long day zone. For example the long day zone gets up to 14-16 earth days of daylight, but only 13-11 earth days of night.
- Gravity is 75% Earth's
- Thicker atmosphere
- 2:1 tidal resonance (2 rotations per 27 Earth day orbit)
- Long days and long nights due to a 27 Earth day diurnal cycle (sunrise to sunrise).
- Planet is overall warm (freezing temps are rare). So no need to adapt to that.
- No "seasons" (in the Earth sense) to speak of. The primary cycle in a location is the day/night cycle, which depends on the respective ratio of day/night.
First things first...the spectrum output of the star is far different than Sol's output, so the photosynthetic pigments that organisms use would be different. After some reading I've determined the color pallet of the "plants" on my world will largely be dark and desaturated purple, blue, and teal. In the zones of longer night the plants will largely look black. Photosynthesis will peak around 1,045nm, well into the near-infrared, though lower wavelengths of visible light will be utilized as well (orange, red).
Photosynthesis cycles will be different of course. Photosynthesis won't produce quite as much energy as it does in the sunniest areas on earth. Also there will be a longer period of activity and dormancy during the long days and nights.
But other than that...I'm not sure. I don't want the photosynthetic organisms to be too similar to Earth's, but I don't know enough about plant ecology to readily spin off ideas on what plausible differences are likely to evolve. What do you guys think? What am I missing besides the difference in pigmentation?