sentence2_structure: Ocean acidification<>occurs<>when excess carbon dioxide in the atmosphere causes the oceans to become acidic$$$excess carbon dioxide in the atmosphere<>causes<>the oceans to become acidic$$$the oceans<>to become<>acidic
sentence1: Ocean acidification describes the decrease in ocean pH that is caused by anthropogenic carbon dioxide (CO2 ) emissions into the atmosphere.
sentence2: Ocean acidification occurs when excess carbon dioxide in the atmosphere causes the oceans to become acidic.
question: What occurs when excess carbon dioxide in the atmosphere causes the oceans to become acidic?