( ( The ( deep-ocean currents ) ) ( ( differ ( from ( ( surface currents ) ( ( in that ) ( they ( ( are density ) driven ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ deep-ocean) (NNS currents)) (VP (VBP differ) (PP (IN from) (NP (NP (NN surface) (NNS currents)) (SBAR (WHPP (IN in) (WHNP (WDT that))) (S (NP (PRP they)) (VP (VBP are) (ADVP (RB density)) (VP (VBN driven)))))))) (. .)))
The deep-ocean currents differ from surface currents in that they are density driven.
(ROOT (S (NP (JJ Deep) (NNS currents)) (VP (VBP are) (VP (VBN caused) (PP (IN by) (NP (NP (NNS differences)) (PP (IN in) (NP (NN density))))) (PP (IN at) (NP (NP (DT the) (NN top) (CC and) (NN bottom)) (PP (IN of) (NP (DT the) (NN ocean))))))) (. .)))