Ocean 'Amplifier' Speeds Up Acidification on US West Coast

Predicting how fast the ocean turns more acidic is a complex challenge, especially in dynamic regions like the California Current System (CCS). This productive upwelling system, which runs along North America's west coast, is influenced by both human-caused carbon emissions and a host of natural processes.

To uncover the region's history, scientists turned to cold-water orange cup corals. By analysing the boron isotopes in their skeletons—a technique that serves as a pH proxy—researchers reconstructed past acidity levels in the CCS and the nearby Salish Sea.

The results, combined with complementary modelling, reveal a worrying trend. Over the industrial era, this marine environment has experienced 'amplified acidification'. The interaction between anthropogenic CO2 and a natural thermodynamic effect has caused the water's acidity to increase faster than the rise in atmospheric CO2 alone would suggest.

Projections indicate this accelerated pace will continue throughout the 21st century, posing profound challenges to the marine ecosystems that are of immense biological, cultural, and economic importance to the region.