I believe the easy solution is actually to have life apearing on your planet when it already has a nine-years day.

If you are thinking about how an ecossystem would thrive for so long without "plants", remember that photosynthesis is not a requirement for life to exist. Many biologists believe that life on Earth started up in the depths of the ocean, where no light reaches. In such places, the source of energy for the ecosystem is chemosynthesis rather than photosynthesis.

So you could throw in a mix - at the day-side of the planet, life thrives with plants at the base of the food chain. At the dark side, it's chemosynthethic beings - not necessarily microscopic life, you could have chemosynthetic fungi in your world.

When it starts to get dark, plants produce seeds or spores that will stay dormant for nine years before they start growing. And when daylight begins to appears, the chemosynthetic lifeforms produce spores that will stay latent for nine years before they restart their part of the cycle.

This would create an interesting effect... With plants and chemosynthetizers appearing as a "wave" in one side of the planet and dying at the same rate on the other side, at the points where it's dawn or dusk.

Or, you could completely drop photosynthesis and go chemosynthetic all the way.

See also this question about a world where it is perpetually dark. You could get some ideas for survival on the dark side of your planet.

I believe the easy solution is actually to have life apearing on your planet when it already has a nine-years day.

If you are thinking about how an ecossystem would thrive for so long without "plants", remember that photosynthesis is not a requirement for life to exist. Many biologists believe that life on Earth started up in the depths of the ocean, where no light reaches. In such places, the source of energy for the ecosystem is chemosynthesis rather than photosynthesis.

So you could throw in a mix - at the day-side of the planet, life thrives with plants at the base of the food chain. At the dark side, it's chemosynthethic beings - not necessarily microscopic life, you could have chemosynthetic fungi in your world.

When it starts to get dark, plants produce seeds or spores that will stay dormant for nine years before they start growing. And when daylight begins to appears, the chemosynthetic lifeforms produce spores that will stay latent for nine years before they restart their part of the cycle.

This would create an interesting effect... With plants and chemosynthetizers appearing as a "wave" in one side of the planet and dying at the same rate on the other side, at the points where it's dawn or dusk.

Or, you could completely drop photosynthesis and go chemosynthetic all the way.

See also this question about a world where it is perpetually dark. You could get some ideas for survival on the dark side of your planet.

I believe the easy solution is actually to have life apearing on your planet when it already has a nine-years day.

If you are thinking about how an ecossystem would thrive for so long without "plants", remember that photosynthesis is not a requirement for life to exist. May biologists believe that life on Earth started up in the depths of the ocean, where no light reaches. In such places, the source of energy for the ecosystem is chemosynthesis rather than photosynthesis.

So you could throw in a mix - at the day-side of the planet, life thrives with plants at the base of the food chain. At the dark side, it's chemosynthethic beings - not necessarily microscopic life, you could have chemosynthetic fungi in your world.

When it starts to get dark, plants produce seeds or spores that will stay dormant for nine years before they start growing. And when daylight begins to appears, the chemosynthetic lifeforms produce spores that will stay latent for nine years before they restart their part of the cycle.

This would create an interesting effect... With plants and chemosynthetizers appearing as a "wave" in one side of the planet and dying at the same rate on the other side, at the points where it's dawn or dusk.

Or, you could completely drop photosynthesis and go chemosynthetic all the way.

See also this question about a world where it is perpetually dark. You could get some ideas for survival on the dark side of your planet.

I believe the easy solution is actually to have life apearing on your planet when it already has a nine-years day.

If you are thinking about how an ecossystem would thrive for so long without "plants", remember that photosynthesis is not a requirement for life to exist. Many biologists believe that life on Earth started up in the depths of the ocean, where no light reaches. In such places, the source of energy for the ecosystem is chemosynthesis rather than photosynthesis.

So you could throw in a mix - at the day-side of the planet, life thrives with plants at the base of the food chain. At the dark side, it's chemosynthethic beings - not necessarily microscopic life, you could have chemosynthetic fungi in your world.

When it starts to get dark, plants produce seeds or spores that will stay dormant for nine years before they start growing. And when daylight begins to appears, the chemosynthetic lifeforms produce spores that will stay latent for nine years before they restart their part of the cycle.

This would create an interesting effect... With plants and chemosynthetizers appearing as a "wave" in one side of the planet and dying at the same rate on the other side, at the points where it's dawn or dusk.

Or, you could completely drop photosynthesis and go chemosynthetic all the way.

See also this question about a world where it is perpetually dark. You could get some ideas for survival on the dark side of your planet.