Ocean acidification is a relatively unknown but serious consequence of climate change. As the world’s oceans absorb more carbon dioxide (CO2) from the atmosphere, the chemical composition of seawater changes, becoming more acidic. This process poses a major threat to marine ecosystems, particularly coral reefs, shellfish, and species that rely on calcium carbonate for their survival.

When CO2 dissolves in seawater, it reacts with water to form carbonic acid. This acid lowers the pH of the ocean, which in turn reduces the availability of carbonate ions—an essential building block for the skeletons and shells of marine organisms like corals, mollusks, and certain types of plankton. Without enough carbonate ions, these creatures struggle to build and maintain their protective structures, leading to weaker and more fragile species.

Coral reefs, often referred to as the rainforests of the sea, are particularly vulnerable. Acidic waters reduce the rate at which corals can build their calcium carbonate skeletons, making them more susceptible to erosion and less able to recover from damage caused by bleaching or storms. Since coral reefs support about 25% of all marine life, their degradation threatens entire ecosystems and the human communities that depend on them.

Beyond coral reefs, ocean acidification also affects fisheries and aquaculture industries. Shellfish like oysters, clams, and mussels are finding it harder to develop strong shells, leading to higher mortality rates in hatcheries and farms. This poses a significant risk to coastal economies that rely on seafood as a major source of income and food security.

Addressing ocean acidification requires reducing global CO2 emissions, the primary driver of the problem. However, local actions can also help. Reducing pollution, restoring coastal habitats like mangroves and seagrass beds, and managing fisheries sustainably can increase the resilience of marine ecosystems to acidification.

In summary, ocean acidification is a silent but serious threat to marine biodiversity and human livelihoods. Combatting this issue requires urgent global action on climate change and careful management of marine resources.