( ( Some ( of ( this ( carbon dioxide ) ) ) ) ( ( is ( being ( absorbed ( by ( our ( oceans ( to ( create ( carbonic acid ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT Some)) (PP (IN of) (NP (DT this) (NN carbon) (NN dioxide)))) (VP (VBZ is) (VP (VBG being) (VP (VBN absorbed) (PP (IN by) (NP (PRP$ our) (NNS oceans) (S (VP (TO to) (VP (VB create) (NP (JJ carbonic) (NN acid)))))))))) (. .)))
Some of this carbon dioxide is being absorbed by our oceans to create carbonic acid.
(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.