Ocean Acidification and its Effect on Coral Reefs
Figure 2. A) Effect on anthropogenic CO2 emissions on the ocean carbonate chemistry and coral calcification. B) Projections of the temperature, atmospheric concentration of CO2, and carbonate concentrations in the ocean in the past, present, and the future. (derived from Hoegh-Guldberg et al. 2007)
Over the past 250 years, the emission of carbon dioxide (CO2) has increased substantially due to human activities such as fossil fuel combustion and deforestation (Doney et al. 2009). This increase in atmospheric carbon dioxide levels has an acidifying effect on the ocean, as the surface of the ocean absorbs about one-third of the excess atmospheric CO2, shifting the carbonate chemistry in the ocean and lowering the pH as seen in figure 2 (Doney et al. 2009). Ocean acidification has a direct and detrimental effect on marine organisms that build shells from calcium carbonate, such as corals (Doney et al. 2009). The lack of carbonate as a building substrate for the shells leads to the death of corals, also termed coral bleaching. Although other cnidarians, such as sea anemones that do not have calcified body parts may remain healthy even with the increase in CO2 levels and subsequent decrease in carbonate levels, the overall fitness of the organisms would still be affected due to the lack of surrounding coral skeleton that provide protection (Doney et al. 2009). Coral reefs are among the most biologically diverse ecosystems in the world, and their decline would affect not only their fellow cnidarians, but all of the marine community within it as well, including the clownfish (Hoegh-Guldberg et al. 2007).
This webpage was completed by Amy Kim as an assignment for BIOL 3236: Biological Adaptation to Climate Change at the University of Queensland, Australia.
This webpage was completed by Amy Kim as an assignment for BIOL 3236: Biological Adaptation to Climate Change at the University of Queensland, Australia.