If DIC stands for dissolved inorganic carbon, then it can be highlighted that DIC in general remains as carbondioxide, carbonate and bicarbonate fractions.Hence if it remains as carbon-di-oxide form, then pH may decrease, but seawater is strongly buffered by carbonate/bicarbonate components which on hydrolysis produces hydroxyl ions that can efficiently neutralise the acid effect. Besides, various minerals present in marine sediments also contribute buffering action, even more than the aquatic system. As a result, it is very difficult to disrupt the combined buffering capacity of marine system.Thus, carbondioxide is trapped by carbonate producing bi-carbonate in aquatic phase and minerals in sediments. When this buffering capacity is lost, only then pH value may decrease.