intertidal zone vs seashore

intertidal zone

noun
  • The part of a shore between high water and low water, especially the beach exposed at maximum ebb spring tides. 

seashore

noun
  • The foreshore, the strip of land between low water and high water. 

  • The coastal land bordering a sea or an ocean. 

How often have the words intertidal zone and seashore occurred in a corpus of books? (source: Google Ngram Viewer )