( ( Ocean acidification ) ( ( describes ( ( ( the decrease ) ( in ( ocean pH ) ) ) ( that ( is ( caused ( by ( ( anthropogenic ( carbon ( dioxide ( ( -LRB- ( CO2 -RRB- ) ) emissions ) ) ) ) ( into ( the atmosphere ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Ocean) (NNP acidification)) (VP (VBZ describes) (NP (NP (DT the) (NN decrease)) (PP (IN in) (NP (NN ocean) (NN pH))) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (VP (VBN caused) (PP (IN by) (NP (NP (JJ anthropogenic) (NN carbon) (NN dioxide) (PRN (-LRB- -LRB-) (NP (NNP CO2)) (-RRB- -RRB-)) (NNS emissions)) (PP (IN into) (NP (DT the) (NN atmosphere))))))))))) (. .)))
Ocean acidification describes the decrease in ocean pH that is caused by anthropogenic carbon dioxide (CO2 ) emissions into the atmosphere.
(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.