Projecting extremes in California Current acidification

With the substantial use of fossil fuels as a source of energy, the concentration of carbon dioxide in the atmosphere has increased significantly. Much of this anthropogenic carbon has been absorbed into the ocean, forcing a chemical reaction with water that culminates in the acidification of the ocean. The acidification of the ocean causes the decrease in carbonate ion concentration, creating an undersaturated system that increases susceptibility to shell dissolution. Modeling studies of the California Current system have projected drastic and rising acidification levels in this region of the ocean within the following century, implying a stressful future for all members of the system’s food web and the fishing industry. Using the Community Earth System Model – Large Ensemble (CESM-LE) projected changes in the frequency of acidification events are analyzed on a monthly basis from 1920 through 2100 in the California Current system. Additionally, seasonal trends are calculated using saturation depth data in order to gain insight on mechanisms of acidification events. Furthermore, a case study of the CCE1 and CCE2 buoys is used for future validations of the CESM-LE projections. Results demonstrate how the frequency of acidification events is expected to rise more quickly than hypothesized, and how undersaturated water levels are rising to depths higher than ever recorded in history.