underwater archaeology vs marine archaeology

underwater archaeology and marine archaeology both are nouns.

Word	Noun	Adjective	Verb	Adverb
underwater archaeology	Yes	No	No	No
marine archaeology	Yes	No	No	No

As nouns, underwater archaeology and marine archaeology are synonyms defined as:

underwater archaeology and marine archaeology: the archeology of underwater sites

Other synonyms of underwater archaeology include marine archeology, underwater archeology.

underwater archaeology (noun)	marine archaeology (noun)
the archeology of underwater sites	the archeology of underwater sites