Incorporating Coastal Acidification Indicators into the National Coastal Condition Assessment Survey
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Coastal and estuarine areas are experiencing declines in pH at a more rapid pace then in the open ocean, which are believed to be driven in part by local factors such as nutrient inputs. Coastal communities are experiencing economic impacts of coastal acidification, particularly the shellfish industry. To better assess vulnerability of coastal waters to acidification, EPA incorporated total alkalinity as a pilot indicator in the 2020/2021 National Coastal Condition Assessment, a statistically based water quality survey conducted by the EPA’s Office of Water and Office of Research and Development, in partnership with coastal states in the contiguous U.S. This presentation reviews the successes and challenges associated with the coastal acidification indicator in the 2020/2021 survey and presents the proposed approach for this indicator in the 2025 survey. Despite dealing with challenges associated with a global pandemic, wildfires, and global shortage of reference material, this effort was a success. ORD and partners collected and analyzed total alkalinity samples from almost 900 estuarine sites across 20 coastal states. This dataset represents the first nationwide dataset of high-quality total alkalinity measurements for our nation’s estuaries that was collected and analyzed using uniform sample collection and analysis methods.