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: Some of this carbon dioxide is being absorbed by our oceans to create carbonic acid.
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?