premise: and Global ocean measurements of ocean-atmospheric carbon dioxide exchange and atmosphere-ocean-biology interactions.
hypothesis: Ocean acidification occurs when excess carbon dioxide in the atmosphere causes the oceans to become acidic.
hypothesis_graph_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