Answer: benthos

AnswerCrossword Clue
BENTHOSBottom of sea.
BENTHOSBottom of the sea.
BENTHOSSea-bottom
BENTHOSBottom of a sea or lake
benthosthe biogeographic region that includes the bottom of a lake, sea, or ocean, and the littoral and supralittoral zones of the shore
benthosthe flora and fauna of the ocean floor