The ocean absorbs carbon dioxide from the atmosphere. The level of atmospheric carbon dioxide has been increasing and the oceans have become more acidic. Some people do not understand the gravity of the oceans becoming more acidic, but they do affect corals and the ability of shellfish to form shells. Oceans play a very important role in the global carbon cycle and have removed 25% of the carbon dioxide that has been emitted by human activities between 2000 and 2007. Rising the ocean temperature and ocean acidification means that the capacity of the ocean carbon sink will slowly get weaker which will give a rise to global concerns.
A report from scientists published in May 2008 that there was found large amount of acidified water are bursting within four miles of the Pacific continental shelf of North America. This area has been identified as a critical zone because that is where most marine life lives or is born.