ocean bottom vs sea bottom

ocean bottom and sea bottom both are nouns.

Word	Noun	Adjective	Verb	Adverb
ocean bottom	Yes	No	No	No
sea bottom	Yes	No	No	No

As nouns, ocean bottom and sea bottom are synonyms defined as:

Other synonyms of ocean bottom include Davy Jones's locker, Davy Jones, ocean floor, sea floor, seabed.

ocean bottom (noun)	sea bottom (noun)
the bottom of a sea or ocean	the bottom of a sea or ocean