Rising anthropogenic, or human-caused, carbon dioxide in the atmosphere may have up to twice the impact on coastal estuaries as it does in the oceans because the human-caused CO2 lowers the ecosystem’s ability to absorb natural fluctuations of the greenhouse gas, a new study suggests.

Researchers from the U.S. Environmental Protection Agency and Oregon State University found that there was significant daily variability when it comes to harmful indices of CO2 for many marine organisms in estuaries. At night, for example, water in the estuary had higher carbon dioxide, lower pH levels, and a lower saturation state from the collective “exhale” of the ecosystem.

These night-time harmful conditions are changing about twice as fast as the daily average, the researchers say, meaning the negative impacts on shell-building animals, including oysters, clams and mussels, may manifest more quickly than expected from simply observing the daily average.

Results of the study are being published April 2 in Proceedings of the National Academy of Sciences. The study was funded and led by the EPA’s Office of Research and Development and Region 10, through a Regional Applied Research Effort grant. The project was coordinated by Stephen Pacella, an EPA scientist who also is a doctoral student in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

Source: Estuaries may experience accelerated impacts of human-caused CO2