A simple diagram depicting the natural flow of carbon through the three carbon sinks. Image courtesy of: http://en.wikipedia.org/wiki/File:CO2_pump_hg.png
The threat posed upon corals is further propagated by the effect of acidification on their food source, plankton. Many species of plankton form exoskeletons out of CaCO3, much like corals. Models predict that within 100 years, global pH will inhibit the exoskeleton formation in these microorganisms so much so that they will not be able to survive. The images above show the structural calcification of phytoplankton now (left) compared to structural calcification under predicted concentrations one century from now (right). The images indicate that calcification is inhibited by acidification, and causes structural deformities in phytoplankton growth. The most obvious difference in the two images is the spacing of calcified plates. Under normal (current) conditions plates are evenly distributed, providing sufficient protection from the elements, but under conditions of increased acidification the plates do not form evenly and are perforated and broken. This could prove to be devastating for phytoplankton and anything that feeds on them.