( ( The Benthos ) ( ( is ( ( ( the seafloor ) and ) ( ( the organisms ) ( that ( live there ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNPS Benthos)) (VP (VBZ is) (NP (NP (DT the) (NN seafloor)) (CC and) (NP (NP (DT the) (NNS organisms)) (SBAR (WHNP (WDT that)) (S (VP (VBP live) (ADVP (RB there)))))))) (. .)))
The Benthos is the seafloor and the organisms that live there.
(ROOT (S (NP (NP (VBG Living) (NNS things)) (PP (IN on) (NP (DT the) (NN ocean) (NN floor)))) (VP (VBP are) (VP (VBN known) (PP (IN as) (NP (NNS benthos))))) (. .)))
Living things on the ocean floor are known as benthos.