Picture retried from NOAA

Ocean acidification (OA) is a consequence of seawater absorbing carbon dioxide. As described by the National Oceanic and Atmospheric Administration (NOAA), there are chemical reactions that cause increased hydrogen ions in the ocean, which decreases the pH of the water, and  reduces the concentration of carbonate ions. This is important because carbonate is a component calcium carbonate – the building block of many marine organisms skeletons and shells.

Additional learning: this diagram featured on CoastAdapt illustrates how the input of carbon dioxide affects the ocean, and this video by NOAA helps visualize OA with detail.