Ocean Acidification

Illustration of the ocean's role in the global carbon cycle.
The ocean's role in the global carbon cycle.

The ocean has become more acidic over the past century because of an increase in the amount of carbon dioxide it is absorbing from the atmosphere, leading to a lower pH and greater acidity. This is causing a fundamental change in the chemistry of the ocean from pole to pole. See NOAA, What is Ocean Acidification?  The increased acidity of ocean and coastal waters is a growing concern because it’s reducing the saturation or availability of calcium carbonate minerals that are the building blocks for the skeletons and shells of many marine organisms.  The growing concern about acidity has led to an increase in research, monitoring and the development of management measures. A number of international bodies are considering measures to address or mitigate the effects of ocean acidification.

A Global Ocean Acidification Observing Network (GOA-ON) has been established at the International Atomic Energy Agency (IAEA) to facilitate international cooperation in monitoring the effects of ocean acidification. The Intergovernmental Oceanographic Commission (IOC) is cooperating with the International Maritime Organization (IMO) on research regarding ocean fertilization and sea level rise. The IOC has contributed to research on ocean fertilization by responding to requests for scientific and technical information. There are also a number of United States domestic programs executing U.S. law related to ocean acidification.

In 2009, Congress enacted the Federal Ocean Acidification Research and Monitoring Act, 33 U.S.C. 3701 et seq. to develop and coordinate a comprehensive interagency plan to monitor and conduct research on the processes and consequences of ocean acidification on marine organisms and ecosystems including the establishment of an ocean and coastal acidification program within NOAA. See NOAA’s Ocean Acidification Program (OAP).  NOAA and other federal government agencies are also undertaking research and exploring mitigation measures to address ocean acidification through the Interagency Working Group on Ocean Acidification (IWGOA) and its Strategic Plan for Federal Research and Monitoring of Ocean Acidification. There are also efforts to enhance natural carbon sinks like forests, mangroves, salt marshes and seagrass beds, which can absorb large quantities of carbon dioxide from the atmosphere, or to create new sinks through silviculture or green agriculture. See NOAA, Coastal Blue Carbon. These efforts also include strategies for intervention or engineering (sometimes referred to as geoengineering).

Carbon Capture and Storage (CCS) may be one of the most promising approaches to reducing carbon dioxide concentrations in the atmosphere in the short and medium term. CCS generally involves the capture of carbon dioxide directly from industrial or power plant fossil-fueled sources – carbon dioxide that would otherwise enter the atmosphere and eventually penetrate into deep ocean waters. Capture is then followed by removal of the carbon dioxide to secure subsurface reservoirs for long-term storage, either on land or beneath the seabed of the ocean.  

Additional reference information: Some of these links are to external sites.

Illustration of the ocean's role in the global carbon cycle.
The ocean's role in the global carbon cycle.