Resource partitioning would most likely occur between populations of sympatric species with similar ecological niches.
Explanation:
Resource partitioning is when limited resources are divided between species to avoid competition in an ecological niche. Resource partitioning occur between populations of sympatric population(species that coexist in the same geological area) and their ecological niche. This is because similar group of species compete the same way for limited resources.
The atmosphere is a reservoir for carbon and nitrogen and cannot be a reservoir for phosphorous. This is because the phosphorous cycle does not include gaseous phase.