Science Reporting

The acidification of the sea off California is twice as fast as the global level

The waters off California are showing a level of acidification twice as fast as the global ocean average. NOAA researchers have obtained this result by analyzing the small microscopic shells found in these areas, shells, and remains of microscopic animals called foraminifers.

They took about 2000 samples of these remains off the coast of Santa Barbara measuring how they have changed over the last 100 years. These shells, in fact, belong to small dead animals and fall to the ocean floor practically every day and are then immediately covered with sediment. The sediment layers themselves therefore represent a sort of vertical recording of climate and environmental changes, including the same level of water acidification.

Looking back in time and measuring the changes in shell thickness, the researchers have obtained an estimate, which they themselves define as “very accurate,” of the level of acidity in this marine area, as explained by Emily Osborne, a scientist who is working in the context of the Ocean Acidification Program and who describes this new technique in a statement that appeared on the site of NOAA itself.

This fossil documentation has shown a sort of cyclical pattern: although the increase in the acidity level of this marine area is quite clear from 1895 to the present day, there have been ten-year changes that have seen a rise or fall in the acidity level itself. According to researchers, these patterns are linked to the Pacific Decadal Oscillation (PDO), a marine phenomenon that sees cooling and warming cycles. This phenomenon can guide and influence the acidification levels of the sea as, among other things, man can do with his carbon dioxide emissions.

“During the cold phases of the Pacific’s decadal oscillation, stronger winds across the ocean push upward the carbon dioxide rich waters to the surface along the west coast of the United States,” Osborne explains. “It’s like a double hammer that increases ocean acidification in this region of the world.”