My story begins with a group of colonists on a ship when something happens (spoilers) and the colonists are forced to abandon ship and land on a nearby uncharted moon of a gas giant.
The good news: they have enough rations for a good long while and a couple of seeds and plants for farming. The moon has an atmosphere with oxygen, nitrogen (with a couple things I’ll get to later) and oceans worth of water. The landmasses on this moon are volcanic islands (think Hawaii or Iceland), meaning that the ground is fertile. Also the moon has a thriving biosphere, meaning plenty of plants and animals.
Now the bad news: the atmosphere has a lot of ammonia in it. I hesitate to give a concrete percentage (I’ve been burned and yelled at before) but I will say enough that a all of the local wild life has a good deal of ammonium in their tissue (like certain squids use for buoyancy) and the air isn’t breathable for terrestrial organisms (don’t take your helmet off).
Now I did do some research into ammonia before posting this so I know that ammonia is lighter than air (which gives me quite a few ideas for the flying animals on this moon) it is corrosive (which gives me a few ideas for how murphy’s law can run amuck) and that it reacts with moisture (such as the ocean and a persons lungs). So what this tells me is that my astronauts are stuck on a moon with air they can’t breathe, creatures they can’t eat and most probably water they can’t drink.
Now most of the is set up for a “science the s#%t out this” style story (like the Martian, The new Lost in Space and parts of the Expanse). The only problem is my expertise relates to biology and paleontology, not chemistry. So what I would like to know is how would someone with equipment to settle a new world deal with this? How would they filter the ammonia from the water and soil? Would it be possible to filter out the ammonium from the creatures to make something remotely edible? Can a group of people set to colonize this world?