A planet on the edge between anaerobic and aerobic life forms. Possibly by Asimov [duplicate]

Question

I read this short story at least 40 years ago. I don't remember where, probably a collection. It has a rather "Asimov" taste but he wrote so many short stories...

It takes place on a very special planet, which is exactly on the "edge" between anaerobic life forms and aerobic ones. There is still a lot of CO2 in the atmosphere, but free oxygen is building up through photosynthesis. But there are not enough plants to push the biosphere fully over this "edge".

There are only two humans there. Maybe they arrived there by accident, but I think they were sent on purpose. Anyway, they cannot leave, their spaceship does not work anymore.

They try to help the transition to aerobic life, to open a new planet to human colonisation, by planting a lot of trees. They hope that someday mankind will, either remember them, or rediscover this planet by pure chance. But the trees do not grow well, and after many years the ratio of free oxygen to CO2 has not changed. Well, I would not expect just the few trees that two people can plant to change the atmosphere of a full planet, but somehow they were hoping for a positive feedback effect.

Finally one of them gets very sick, or just too old, and asks the other one to bury him, when he dies, directly in the ground and plant a tree over him.

And helped by the nutrients from the decomposition of his corpse the tree grows fast, the positive feedback effect begins and the planet is finally pushed over the edge to aerobic life forms. (Not very likely if you ask me... but I did not write this story !)

Answer 1

This is "Founding Father" by Asimov, originally published in the October 1965 issue of Galaxy.

An exploratory spacecraft of the Galactic Corps, charged with opening up planets for human colonisation, sometimes by terraforming, crash-lands on an alien planet. They find that the ecology is heavy in ammonia, making the atmosphere unbreathable by humans, and the soil unsuitable for the Earth-type plants they have brought for colonisation.

As they are unable to take off again, the crew spend their time trying to adjust the environment to make it suitable for possible future human colonists, by cultivating Earth plants which will create oxygen. Although they spend many years at this task, they fail and, one by one, they die of ammonia poisoning.

As the last man dies, the flesh of the buried crew feeds the plants and finally helps them to flourish, providing the catalyst that alters the environment to become more Earth-like.