Keynote: Ocean Acidification and Living Marine Resources

As atmospheric carbon dioxide levels have risen because of human activities, they have also decreased ocean pH and profoundly altered seawater carbonate chemistry. These chemical changes have been observed at time-series ocean monitoring stations around the world.Global ocean models show that the chemical changes will continue in tandem with continued increases in atmospheric carbon dioxide. In addition to altering ocean biogeochemical cycles of inorganic species, ocean acidification has the capacity to affect marine life in direct and indirect ways. One of the best-studied direct effects of ocean acidification are alterations in calcification rate of animals with calcium carbonate shells and skeletons, such as plankton, mollusks, and corals. Other effects of ocean acidification on marine species that are now under investigation include changes in respiration, acid-base balance, reproduction, settlement, excretion, and behavioral changes. Any of these changes have the potential to affect ocean ecosystems by altering trophic relationships, habitat, or other life functions.Major areas of current research include examining the natural tolerance of marine organisms for changes in ocean chemistry, their abilities to adapt to new conditions via behavioral or genetic adaptations, and the interactions of ocean acidification with other environmental stressors. Some insight is available from studies of past geological periods, but the present changes are occurring much faster than any in the past.