The oceans are an important sink for atmospheric CO2, but as they take up increasing amounts of CO2 they are becoming more acidic.
This has knock-on effects on some marine organisms and on the ocean's ability to sequester carbon. NIWA oceanographer Dr Cliff Law explains the impacts of ocean acidification on organisms that use carbonates to build their shells, and on bacteria. Effects on bacteria may reduce the ocean's ability to take up atmospheric CO2, creating a positive feedback loop, whereas organisms that use carbonate may find it more difficult to form and maintain their shells. (07:00)