What are the domains of Earth Science?
Regarding subdomains - I expect that there may be hundreds or thousands of subdomain *spheres. 

For example, I've studied soil for many years and had never heard of the "drillosphere", "porosphere", "aggregatusphere", or "detritusphere".


  “drilosphere” (the portion of the soil volume influenced by secretions
  of earthworms), the porosphere (the total pore space), detritusphere
  (dead plant and soil biota), aggregatusphere (the sum of aggregates)
  and the rhizosphere.


from fig 4 in the same Nature Education article that provided the macro-view venn diagram in @blunders' answer.

(source: nature.com)