
The oceans are becoming more acidic because of the rapid release of carbon dioxide (CO2) caused by anthropogenic (human) activities, such as burning of fossil fuels. So far, the oceans have taken up around 30% of all anthropogenic CO2 released to the atmosphere. The continuous increase of CO2 has a substantial effect on ocean chemistry because CO2 reacts with water and carbonate molecules. This process, called ‘ocean acidification,’ lowers pH, and calcium carbonate becomes less available. This is a problem for calcifying organisms, such as corals and molluscs, that use calcium carbonate as the main building blocks of their exoskeleton.
In particular, organisms that build their shells from a type of calcium carbonate known as ‘aragonite’ are in trouble because aragonite is extremely soluble in sea water. Sea butterflies, tiny, swimming sea snails, build their shells of aragonite. Therefore, they are also known as ‘the canaries of the coalmine’ because they are expected to be amongst the first organisms to be affected by ocean acidification.
Continue reading ‘Sea butterflies already struggle in acidifying Southern Ocean’