Caldeira Lab Research:Ocean acidification and ocean carbon cycle

What Corals are Dying to Tell Us About CO2 and Ocean Acidification

Ken Caldeira

The human population is currently dumping tons upon tons of CO2 into the ocean, creating an acidifying effect as the gas is converted into carbonic acid. This event could have dire consequences -- it mirrors the effects that the comet impact 65 million years ago had on the Earth's ocean, provoking a mass extinction that it did not recover from for millions of years.

Caldeira, K, 2007. What Corals are Dying to Tell Us About CO2 and Ocean Acidification, Oceanography 20 (2):188-195.

Organisms threatened by ocean acidification: much of marine life is highly dependent on the presence of calcium carbonate to survive. All of these animals are greatly threatened by rising ocean acidification, as the building blocks of their existence could begin to slowly disintegrate.

Atmospheric carbon concentration and its effect on ocean pH: even following an abrupt and unexpected end to carbon dioxide emissions, oceanic absorption would continue well into the future, which could easily lead to dangerously low pH.

Corals and predation: even in an ocean with low acidity, corals still need to reproduce fast enough to match their predators. If their production was curtailed by acidity, the effects of predation on their lifespan would be magnified, creating an even greater rate of decline for population.


Emissions of carbon dioxide are causing the oceans to become more acidic. Recent experiments show that this ocean acidification threatens many ocean ecosystems. The ancient past may provide a cautionary tale, indicating what might happen if we change ocean chemistry too much too fast.