Changes in pH and carbonate chemistry force marine organisms to spend more energy regulating chemistry in their cells. For some organisms, this may leave less energy for other biological processes like growing, reproducing corresponding to other stresses.
Ocean acidi!cation (OA) is a progressive increase in the acidity of the ocean over an extended period, typically decades or longer, which is caused primarily by uptake of carbon dioxide (CO2 ) from the atmosphere. It can also be caused or enhanced by other chemical additions or subtractions from the ocean. Acidi!cation can be more severe in areas where human activities and impacts, such as acid rain and nutrient runo%, further increase acidity
Long-term pH decline could exceed the tolerancelimits of marine species that live in coastal waters,even though they may have evolved strategies to deal with&uctuating pH on short timescales typical of coastal environments (where the daily and seasonal changes in seawater pHare much greater than in the open ocean).