One way to understand how ocean acidity can change, for example, in response to rising carbon dioxide (CO2) levels, is to look to the history of seawater acidity. Dr. Itay Halevy of the Weizmann Institute of Science has looked to the distant past – all the way back to Earth’s earliest oceans. The model he developed, together with Dr. Aviv Bachan of Stanford University, suggests that the early oceans, right around the time that life originated, were somewhat acidic, and that they gradually became alkaline. The study, published in Science, sheds light on how past ocean acid levels were controlled by CO2in the atmosphere, an important process for understanding the effects of climate change.
One way to understand how ocean acidity can change, for example, in response to rising carbon dioxide (CO2) levels, is to look to the history of seawater acidity. Dr. Itay Halevy of the Weizmann Institute of Science has looked to the distant past – all the way back to Earth’s earliest oceans. The model he developed, together with Dr. Aviv Bachan of Stanford University, suggests that the early oceans, right around the time that life originated, were somewhat acidic, and that they gradually became alkaline. The study, published in Science, sheds light on how past ocean acid levels were controlled by CO2in the atmosphere, an important process for understanding the effects of climate change.
Acidity and alkalinity are measured on the pH scale of 0-14. On this scale, 7 is neutral, higher is alkaline, lower is acidic. At around 8.2, today’s oceans are mildly alkaline, and we know that rising CO2 levels are currently increasing the oceans’ acidity (decreasing pH).
Halevy, of the Weizmann Institute’s Earth and Planetary Sciences Department, explains that billions of years ago “the early Sun was dimmer, even though we don’t have evidence for a much colder climate. We think that this is because the early atmosphere had more of the greenhouse gas CO2 than at present, and that as the Sun got brighter, CO2 levels decreased,” says Halevy.
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Image via Weizmann Institute of Science
