limnology vs earth science

limnology and earth science both are nouns.

Word	Noun	Adjective	Verb	Adverb
limnology	Yes	No	No	No
earth science	Yes	No	No	No

As nouns, earth science is a hypernym of limnology; that is, earth science is a word with a broader meaning than limnology:

limnology: the scientific study of bodies of fresh water for their biological and physical and geological properties
earth science: any of the sciences that deal with the earth or its parts

limnology (noun)	earth science (noun)
the scientific study of bodies of fresh water for their biological and physical and geological properties	any of the sciences that deal with the earth or its parts