Is increasing acidity in the ocean affecting more than the atmosphere?
Figures from the International Panel on Climate Change show that atmospheric CO2 has increased by over a third in the last 250 years, reaching 379 parts per million in 2005 while the NOAA gives a figure for September 2012 of 390 ppm.
The impacts of such changes are not, however, confined to the atmosphere; a new study from the British Antarctic Survey, NOAA, and the University of East Anglia, has shown that increases in atmospheric carbon dioxide are linked to damage to the shells of microscopic marine creatures called pteropods.
The Oceans: Acidification and Upwelling
Understanding the impacts of increased atmospheric carbon dioxide on the ocean requires some knowledge of how ocean systems work. At the atmosphere-ocean boundary, carbon dioxide passes from air to sea and as it does so, the ocean becomes increasingly acid. In upper levels, some of the excess carbon is removed by precipitating calcium carbonate to form the shells of tiny marine snails.
These creatures, which include a range of aragonite-shelled organisms known as pteropods, are key contributors to the removal of excess carbon: when these creatures die their shells fall to the bottom of the sea, effectively ‘storing’ carbon. Typically, sea water has been found to be saturated with carbonate ions, whose presence in excess is required for shell formation, above depths of around 1000m.