Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused primarily by the uptake of carbon dioxide (CO2) from the atmosphere. This process has serious implications for marine ecosystems, as the increased acidity can impact the ability of organisms such as corals, shellfish, and plankton to build their calcium carbonate shells or skeletons. Ocean acidification is also linked to global climate change, as it is a direct result of the increasing levels of CO2 in the atmosphere. Researchers are studying the effects of ocean acidification on marine life, as well as exploring potential solutions to mitigate its impacts.