How will acidification affect marine ecosystems and fisheries?
Marine organisms that use calcium carbonate (CaCO3) to construct their shells or skeletonsincluding corals, coccolithophores (calcareous phytoplankton), mussels, snails, and sea urchinsare the most vulnerable to acidification. As carbonate becomes scarcer, organisms will find it increasingly difficult to form their skeletal material. For example, decreased calcification rates will slow the growth of coral reefs and make them more fragile and vulnerable to erosion. By the middle of this century, reef erosion may surpass reef-building. In the case of calcareous phytoplankton, part of the marine food web, some organisms likely to be affected by acidification are important prey for those higher up the food chain, including commercially fished species. But it is not yet clear how impacts on individual organisms will propagate through marine ecosystems, or if marine food webs can reorganize themselves to make up for the loss of some key elements. In certain invertebrates and some fish, CO2 a
