July 2015 saw atmospheric CO2 reach average monthly level of 401.30 parts per million, a huge increase on levels recorded in 1959 the first year with full high precision instrument data measurements of 315.97 ppm, and a vast increase on pre-industrial levels of around 280 ppm. With national, regional, and local governments, as well as industry and the public failing to take meaningful steps to reduce emissions, levels are only set to increase. Climate change is perhaps the most well-known consequence of our continued emissions, but of increasing concern is climate change’s “evil twin” – ocean acidification.
Around 30% of atmospheric carbon dioxide is soaked up by the ocean where it forms carbonic acid, which in turn breaks down into bicarbonate and hydrogen ions. Bicarbonate ions can break down further into carbonate ions and a hydrogen ion. It is the increase in the concentration of hydrogen ions that decreases ocean pH. This chemical reaction is entirely natural, but the speed and magnitude of current and predicted change is far greater than known historical rates.
Numerous studies have indicated acidification and in some cases more specifically, saturation state (the amount of carbonate dissolved in seawater relative to the maximum it can hold) will have impacts on marine life, including species used for mariculture.
This article was written for (and appears in full) on The Fish Site.
Image: An oyster farm. Credit Seahorse Digital/Pixabay (CC0)