Estuaries are dynamic coastal ecosystems that experience rapid swings in chemistry. The carbonate chemistry of Southeast estuaries is influenced by respiration of organisms (breathing out carbon dioxide, just like us), the decay of organic material and freshwater outflow from rivers.  Increases in any of these processes would increase carbon dioxide content in coastal waters in addition to ongoing acidification from increasing atmospheric carbon dioxide.

 

The Southeast is one of the most rapidly developing regions of the U.S. Increases in development leads to an increase in impervious surfaces (surfaces that don’t allow rainwater to infiltrate).  This means that there is more freshwater and pollution runoff into coastal ecosystems.  Increases in freshwater reduce the ability of coastal ecosystems to buffer against changes in carbon dioxide, reducing the pH, and making the seawater more acidic. Runoff can also cause increases in nutrients (e.g. from fertilizers) in local waterways leading to algal blooms. Through a mechanism called eutrophication, this also has the potential to alter carbonate chemistry in coastal ecosystems.

 

Though these are very different mechanisms by which carbon dioxide can increase in the ocean and coastal waters, the impacts to coastal organisms may be similar. Understanding the source of changing chemistry is important for mitigation efforts and SOCAN seeks to increase monitoring that will help interpret the source of these changes.