Ocean Acidification

It is well established among researchers that the uptake of increased amounts of carbon dioxide will make ocean water more acidic as the gas dissolves to create carbonic acid. Ocean chemistry is changing 100 times more rapidly than in the 650,000 years that preceded the modern industrial era and since the late 1980s, researchers at Scripps Oceanography and others have recorded an overall drop in the pH of the oceans from 8.16 to 8.05.

This increased acidity can hamper the ability of a wide variety of marine organisms ranging from coral to abalone to form calcium carbonate shells and skeletonal structures. Researchers believe that at crucial stages in the larval and juvenile stages in the lives of many marine invertebrates, ocean acidification inhibits calcification, and also appears to affect reproduction and growth in some organisms.

Scripps Oceanography is emerging as an international center of ocean acidification research.

Late Scripps geochemist Charles David Keeling is best known for his famous record of atmospheric carbon dioxide concentrations known as the Keeling Curve, but he also started the first time series of ocean carbon dioxide content in 1983 near Bermuda.

Scripps marine chemist Andrew Dickson established the reference standards that are used worldwide to ensure the uniform quality of carbon and alkalinity measurements in sewater. Such uniform, high-quality data has been key to helping scientists around the world recognize and understand the nature of ocean acidification.

Scripps physical oceanographer Uwe Send now operates three state-of-the-art moorings that observe carbon system parameters such as levels of dissolved CO2 and pH off the California coast with real-time data delivery from the surface and subsurface, in cooperation with Scripps scientists Mark Ohman and Todd Martz, and colleagues from NOAA. Data can be viewed at http://mooring.ucsd.edu/CCE and http:// mooring.ucsd.edu/DelMar.

The moorings join an open ocean monitoring effort known as OceanSITES. Co-led by Scripps Oceanography, OceanSITES is building a network of stations around the world to collect long time-series measurements of trends in ocean climate and ecosystem dynamics.  Complementary lab work is examining the effect of elevated carbon dioxide on calcification rates in red sea urchins, abalone, and oysters at different life stages.