Like a sponge, our oceans are absorbing increasing amounts of carbon dioxide from the atmosphere. This exchange helps regulate the planet’s atmospheric carbon dioxide concentrations, but comes at a cost for the oceans and sea life, particularly shellfish such as commercially valuable oysters and clams. Ocean acidification is best known for its osteoporosis-like effects on shellfish, which makes building and maintaining shells difficult for these creatures. Acidification also affects other species vital to the marine ecosystem, including reef-building corals and pteropods (tiny snails eaten by numerous species such as fish and whales)."- This definition comes from NOAA