( ( Measurements ( of ( ( carbon dioxide ) ( ( ( in ( the atmosphere ) ) and ) ( in ( the ( upper ocean ) ) ) ) ) ) ) ( ( suggest ( that ( ( the ( Southern Ocean ) ) ( is ( one ( of ( ( the ( primary sinks ) ) ( for ( atmospheric ( carbon dioxide ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Measurements)) (PP (IN of) (NP (NP (NN carbon) (NN dioxide)) (PP (PP (IN in) (NP (DT the) (NN atmosphere))) (CC and) (PP (IN in) (NP (DT the) (JJ upper) (NN ocean))))))) (VP (VBP suggest) (SBAR (IN that) (S (NP (DT the) (NNP Southern) (NNP Ocean)) (VP (VBZ is) (NP (NP (CD one)) (PP (IN of) (NP (NP (DT the) (JJ primary) (NNS sinks)) (PP (IN for) (NP (JJ atmospheric) (NN carbon) (NN dioxide)))))))))) (. .)))
Measurements of carbon dioxide in the atmosphere and in the upper ocean suggest that the Southern Ocean is one of the primary sinks for atmospheric carbon dioxide.
(ROOT (S (NP (NNP Ocean) (NNP acidification)) (VP (VBZ occurs) (SBAR (WHADVP (WRB when)) (S (NP (NP (JJ excess) (NN carbon) (NN dioxide)) (PP (IN in) (NP (DT the) (NN atmosphere)))) (VP (VBZ causes) (S (NP (DT the) (NNS oceans)) (VP (TO to) (VP (VB become) (NP (NNS acidic))))))))) (. .)))
Ocean acidification occurs when excess carbon dioxide in the atmosphere causes the oceans to become acidic.