Effects of Acidity: 4

Ocean acidity is closely linked to carbon dioxide levels (Wikipedia). Increased carbon dioxide levels in the atmosphere can obviously lead to increased carbon dioxide concentrations in the ocean, but the process is more complex than scientists originally believed (See this article for more information). Wind and weather patterns affect the flow of water within the oceans. Two important such patterns are the North Atlantic Oscillation and the Pacific Decadal Oscillation, both of which help circulate ocean water. About two decades ago, the NAO brought more winds to the Atlantic Ocean, bringing to the surface water that was unsaturated with carbon dioxide and thus able to dissolve more from the atmosphere. However, the PDO in its cold phase increases the amount of upwelling, or the movement of carbon dioxide-rich water to the surface. This upwelling allows the ocean to release carbon dioxide into the atmosphere.

This gradual change of increases and decreases in ocean carbon dioxide levels corresponds directly to changes in ocean acidity, which may effect the survival of various marine organisms.

Our knowledge of how ocean acidity will affect marine life is not extensive. Climate change and CO2 production will lead to a gradual decrease in the pH of the ocean by an estimated 0.5 units over the next century. Most studies related to how acidity affects a species have been short term and involve significant deviations from the pH that a species is used to experiencing. Therefore, these studies do not say much about how marine life might be affected by more gradual, long term pH change. Also, due to the diversity of marine life and their abilities to respond to this change, it is hard to make an accurate general prediction of how marine life may be affected by changes in ocean acidity.

It then seems that a good starting point for future research would be to pinpoint these basic physiological processes that allow for such diversity in organismal responses to changing acidinty in the ocean. In addition, some of the diverging data may be caused by differences in experimental methods and models. A unified structure of conducting experiments regarding acidity would help with this problem.

So far, acidity has been looked at most closely in terms of how it affects calcifying organisms, primarily coral. This is because changing pH levels will affect these organisms the fastest and potentially the most drastically and because coral reefs are such an intrinsic part of many marine ecosystems. It is likely, too, that the larval stages of many marine invertebrates will be particularly vulnerable to changes in ocean acidity.

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