Alien biochemistry

[Worldtree]

Are there examples in OA of a one planet hosting major ecosystems of different biochemistries?  By "major" I just mean something more extensive than things like the chemosynthetic bacteria in acid pools around geysers or oceanic tube worms on our planet. 

Do you mean naturally occurring biochemistries? Because there’s plenty of references to megastructures and orbitals and sections of enclosed habitats on various planets where multiple biochemistries are being cultivated - Neptune’s world shell has many environments, for example. https://www.orionsarm.com/eg-article/4f1828a411675