Policy Update

First in Science: Rising Carbon Emissions Are Acidifying Freshwater



NCEL Point of Contact


The impacts of carbon emissions on the acidification of the oceans has been well documented. Now researchers have found that carbon dioxide levels are causing acidification in freshwater systems as well.

The Study

Scientists have struggled to study freshwater acidification due to the complexity of modeling and sampling CO2 in these systems, which comes from a variety of sources such as decomposing organic matter. But researchers in Germany spent 35 years tracking CO2 levels in crustaceans in four different reservoirs and are now able to link the increase in crustacean CO2 to increasing atmospheric CO2, holding all variables constant.

Results & Significance

The increase in CO2 caused freshwater systems to become acidic at a rate three times that of ocean acidification. More acidic waters impact animals lower in the food web–like water fleas–which has a cascading impact on fish, birds, and the larger ecosystem. In the ocean context, acidification has impacted coastal economies through both tourism and job loss.