Fundamental changes in seawater chemistry are occurring throughout the world’s oceans. The release of carbon dioxide (CO2) from our industrial and agricultural activities has increased the amount of CO2 in the atmosphere, a quarter of which is absorbed by the ocean every year. As atmospheric CO2 levels increase, so do the levels in the ocean. This process is called ocean acidification. This change in seawater chemistry moves it closer to the acidic range of the pH scale, although seawater is not expected to become literally acidic.
Among all other harms ocean acidification does, a recent study led by researchers at the University of California, Santa Cruz proves corals are not able to fully acclimate to low pH conditions in nature. This means ocean acidification will reduce the density of coral skeletons, making coral reefs more vulnerable to disruption and erosion. The reduced density of the coral skeletons makes them more vulnerable to mechanical erosion during storms, organisms that bore into corals, and parrotfish, which sometimes feed on corals. This could lead to a weakening of the reef framework and subsequent degradation of the complex coral reef ecosystem.
Combating acidification requires reducing CO2 emissions and improving the health of the oceans. Creating marine protected areas (essentially national parks for the sea) and stopping destructive fishing practices would increase the resiliency of marine ecosystems and help them withstand acidification.
Ultimately, reducing the amount of carbon dioxide absorbed into the oceans may be the only way to halt acidification. The same strategies needed to fight global warming on land can also help in the seas.