Climate change also causes changes in the oceans, which absorbs about one-fourth of the carbon dioxide emitted to the atmosphere each year. Nuclear and isotopic techniques are powerful tools to study the carbon cycle and ocean acidification. These techniques have widely contributed to the understanding of past and present ocean conditions and to predicting the impact of climate change, according to sources from the International Atomic Energy Agency (IAEA).
As the ocean absorbs carbon dioxide (CO2) released into the atmosphere by human activities, the chemistry and acidity of seawater are modified. This process has become a key global issue in the last decade because of its potential to affect marine organisms and biogeochemical cycles.
Nuclear and isotopic techniques are used contribute to the understanding of this process. Researchers look into past changes in ocean acidity and the impacts of ocean acidification on marine organisms and study biological processes like calcification.
The ocean absorbs approximately one fourth of the carbon dioxide released into the atmosphere
Calcification, marine ecosystems and coral reefs
Below a certain pH and its corresponding carbonate concentration conditions become corrosive to calcium carbonate, which is used by many organisms to build their shells and skeletons. Some corals, pteropods, bivalve mollusks and phytoplankton may be particularly sensitive to changes in seawater chemistry. The energy they spend overcoming the higher acidity could reduce the energy available for physiological processes such as reproduction and growth.
Some marine organisms could be especially sensitive to chemical changes in sea water.
Coral reefs are also highly affected. They host some of the most diverse ecosystems on the planet, yet studies have shown that some corals are sensitive to variations in their environment. In the past, ocean acidification episodes in the geological past led to significant changes in ecosystems, including mass extinctions of some deep-sea marine organisms and the collapse of reef-building calcareous algae and corals.
In the past, acidification periods in the ocean caused significant changes to ecosystems
Nuclear and isotopic techniques study the rates of biological processes in marine organisms, such as mussels, oysters and corals. Boron isotopes are used to study past changes in seawater pH; scientists measure their relative amounts in coral skeletons formed thousands of years ago in order to assess past seawater acidity.
Because of the potential impact of CO2 absorption on marine environments and ecosystems, the IAEA’s Environment Laboratories conduct research on topics such as the economic implications of ocean acidification on fisheries. The IAEA also maintains the Ocean Acidification International Coordination Centre (OA-ICC), which helps advance ocean acidification science, capacity-building and global communication.
Nuclear and isotopic techniques study the pH changes in sea water
A major environmental issue of the 21st century
Ocean acidification has emerged as one of the 21st century’s major global threats to marine organisms, ecosystems, and resources and is the specific focus of United Nations Sustainable Development Goal 14.3.
This “other CO2 problem”, still poorly known by the general public, can have potentially dramatic socio-economic consequences for countries depending on marine resources, especially countries with limited possibilities for alternative livelihoods. As world-wide research activities on ocean acidification and related stressors continue to develop, there is a clear need for effective global scientific cooperation.
The 8th of January (08.01) is the Ocean Acidification Day of Action (8.1 is the current pH of the ocean). the IAEA's Ocean Acidification International Coordination Centre released a video describing its work using nuclear and nuclear-derived technologies to better understand and address the issue of ocean acidification. The video explains how climate change is altering the chemistry of oceans and affecting the health of many marine animals: