As a Ph.D. candidate at ETH Zurich I used the Regional Oceanic Modeling System (ROMS) to study the variability of the carbon system and progression of ocean acidification along the US West Coast. Summertime upwelling of subsurface CO2-rich waters causes naturally low pH and aragonite saturation state conditions at the surface and large seasonal variability of the carbon system. The animation shows the seasonal variability of the modeled aragonite saturation state in 2010.
Increased oceanic uptake of CO2 from the atmosphere over the past 160+ years has lowered pH and the carbonate concentration to levels that are harmful to some shelf-building organisms. For example, declined larval growth of oysters at hatcheries in Oregon are linked to increased CO2 levels in seawater that was brought in from the ocean (check out http://seagrant.oregonstate.edu/confluence/2-1/whiskey-creek-1). The animation below shows the modeled evolution of the depth of the saturation horizon with regard to the CaCO3 mineral aragonite (left), and surface ocean pH (right) from present day until 2050 following the IPCC SRES A2 scenario. The video is related to the paper “Rapid Progression of Ocean Acidification in the California Current System” available here: http://www.sciencemag.org/content/early/2012/06/13/science.1216773.full.