( ( Changes ( in ( density ( ( caused ( by ( ( wind and ) currents ) ) ) ( at ( the surface ) ) ) ) ) ) ( ( affects ( the ( deep-ocean currents ) ) ) . ) )
(ROOT (S (NP (NP (NNS Changes)) (PP (IN in) (NP (NP (NN density)) (VP (VBN caused) (PP (IN by) (NP (NN wind) (CC and) (NNS currents))) (PP (IN at) (NP (DT the) (NN surface))))))) (VP (VBZ affects) (NP (DT the) (JJ deep-ocean) (NNS currents))) (. .)))
Changes in density caused by wind and currents at the surface affects the deep-ocean currents.
(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))))))) (. .)))