Ocean Acidification (often referred to as OA) refers to an increase in the acidity of the ocean over an extended period, typically decades or longer, which is caused primarily by uptake of carbon dioxide from the atmosphere (IPCC 2007). It is a great concern as left unchecked and working in concert with the effects of global warming, OA will profoundly affect marine ecosystems and species (Hoegh-Guildberg & Bruno 2010; Veron 2010). For example the world’s coral reef ecosystems will be functionally non-viable once the full effect of current atmospheric CO2 levels take effect (Coral Crisis Working Group position statement 2009; Veron et al 2009, WAZA Position Statement 2010 and Veron 2012).
OA is a great threat to the polar region marine food chains and is already pronounced in these cold region oceans, due to the higher capacity of cold waters to absorb carbon dioxide. The Arctic Monitoring and Assessment Programme’s Arctic Ocean Acidification Assessment report states that indirect OA effects include changes in food supply or other resources. For example, birds and mammals are not likely to be directly affected by acidification but may be indirectly affected if their food sources decline, expand, relocate, or otherwise change in response to ocean acidification. OA may alter the extent to which nutrients and essential trace elements in seawater are available to marine organisms. Some shell-building Arctic molluscs are likely to be negatively affected by OA, especially at early life stages. Juvenile and adult fishes are thought likely to cope with the acidification levels projected for the next century, but fish eggs and early larval stages may be more sensitive. In general, early life stages are more susceptible to direct effects of OA than later life stages (AMAP 2013). Critically important food web species such as pteropods and other calcium carbonate shell building animals are examples of directly vulnerable polar region species, the loss of which reduce the availability of nutrients and the ability of oceans to absorb atmospheric CO2. (IPCC 2007) (Sommerkorn M. 2008).
Find out more:
- Arctic Monitoring and Assessment Programme (2013) Arctic Ocean Acidification Assessment: Summary for Policymakers. Link to Arctic Council Web site
- Fabry, V.J.; Seibel, B.A.; Feely, R.A.; Orr, J.C. Impacts of ocean acidification on marine fauna and ecosystem processes. J. Mar. Sci. 2008, 65, 414–423.
- HOEGH-GULDBERG, O. & BRUNO, J. F. (2010): The impact of climate change on the world’s marine ecosystems. Science 328: 1523–1528.
- Veron, J.E.N.,(2008). Mass extinctions and ocean acidification: biological constraints on geological dilemmas. Coral Reefs 27, 459–472.
- Veron, J.E.N., Hoegh-Guldberg, O, Lenton, T.M, Lough, J.M., Obura D.O., Pearce-Kelly, P., Sheppard, C., Spalding M., Stafford-Smith, M.G. and Rogers, A.D. (2009) The coral reef crisis: The critical importance of <350 ppm CO2. Marine Pollution Bulletin 58 (2009) 1428–1436
- Veron, E.N. (2011) Ocean Acidification and Coral Reefs: An Emerging Big Picture. Diversity 2011, 3, 262-274; doi:10.3390/d3020262
- WAZA (2012): Resolution 67.2. Emergency resolution on avoiding disastrous and unmanageable climate change and ocean acidification impacts by returning atmospheric CO2 concentrations to below 350 parts per million while it is still possible to do so. Gland, Switzerland: World Association of Zoos and Aquariums.