For World Oceans Day, which is celebrated on June 8, our colleagues from the International Atomic Energy Agency (IAEA) have prepared a material explaining how carbon dioxide emissions into the atmosphere cause acidification of the oceans.

Ocean acidification is a consequence of increased carbon dioxide (CO2) emissions causing climate change. The ocean absorbs about a third of all anthropogenic CO2, which leads to a change in the chemical composition of seawater; this phenomenon has been called "ocean acidification". It poses a serious threat to marine life, ecosystems and people whose livelihoods depend on the ocean.

When CO2 dissolves in seawater, it forms carbonic acid (H2CO3), releasing hydrogen ions (H+) and increasing the acidity of the ocean. The level of acidity is important for many biological mechanisms, including calcification.


Calcium carbonate (CaCO3) is necessary for a variety of creatures, including some species of plankton, oysters, crabs, sea urchins, shrimps and lobsters, to form a shell, shell and skeleton. Due to the increased acidity of the ocean, it becomes more difficult for them to preserve calcium-containing structures, which can lead to an imbalance in food chains.
Ocean acidification can also affect the ability of coral reefs to recover from warming and other stressors, as it is more difficult for corals to build their skeletons based on calcium.

Ocean acidification affects both small coastal communities and large industrial enterprises. Damage to aquaculture and tourism means losses for communities that depend on the ocean as a source of food and income. It is estimated that ocean acidification could affect the lives of up to three billion people whose livelihoods depend on marine and coastal biodiversity.


Large shellfish breeding enterprises are also under threat. A study conducted in the United States of America showed that by 2100, due to ocean acidification, the country's shellfish industry could lose more than $400 million annually. Representatives of scientific and industrial circles are looking for ways to minimize the effects of ocean acidification in oyster nurseries.

It is certainly important to develop adaptation methods, but we must not forget about the root cause of the problem – the continued CO2 emissions from the burning of fossil fuels.
In order to develop and implement solutions, it is extremely important to better understand the effects of ocean acidification on the biosphere. Nuclear and isotopic methods, including the use of radio indicators, can play an important role in understanding these processes.


To facilitate research in this area, as well as to promote cooperation, coordination and communication with regard to international activities on the topic of ocean acidification, the IAEA has established an International Coordination Center on Ocean Acidification.

The Center unites the efforts of researchers and organizations from all over the world who conduct scientific and awareness-raising activities in order to develop approaches supported by scientific knowledge to decision-making on this global problem.

Main photo: IAEA/A.Vargas. When CO2 dissolves in seawater, it forms carbonic acid.

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