Gaea vs Gaia

Gaea

Gaia

name
  • The ecosystem of the Earth regarded as a self-regulating superorganism. 

  • A Greek goddess, the personification of the earth, and one of the primordial deities from whom all the others descend. 

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