( ( Most ( river invertebrates ) ) ( ( live ( ( ( ( in ( the benthos ) ) , ) not ) ( in ( water column ) ) ) ) ; ) )
(ROOT (S (NP (JJS Most) (NN river) (NNS invertebrates)) (VP (VBP live) (PP (PP (IN in) (NP (DT the) (NNS benthos))) (, ,) (RB not) (PP (IN in) (NP (NN water) (NN column))))) (: ;)))
Most river invertebrates live in the benthos, not in water column;
(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.