Dead Zones and Mortal Moments: The Expanding Role for Citizen Science in Defining Total Hypoxia in Chesapeake Bay

Dead Zones in coastal estuaries are indicative of poor water quality and degraded ecosystem functions. They are described as areas of low dissolved oxygen or hypoxia, and have been spreading in coastal waters around the globe... [ view full abstract ]

Dead Zones in coastal estuaries are indicative of poor water quality and degraded ecosystem functions. They are described as areas of low dissolved oxygen or hypoxia, and have been spreading in coastal waters around the globe for decades. Chesapeake Bay, located along the eastern seaboard of the Atlantic Ocean, is the largest estuary in the United States with a surface area of 4,479 square miles and a drainage area of approximately 64,000 square miles. It experiences an annual dead zone, mostly in its deepest waters, during the summer season. This event is tracked and reported each year by the United States Environmental Protection Agency’s Chesapeake Bay Program Partnership as a signature measure of overall Bay health. However, both historical and recent water-quality data illustrate that the Bay experiences low dissolved oxygen more extensively in space and time than has been described by the dead zone reports alone. For example, near-shore, high temporal frequency (e.g. a measurement every 15 minutes) water quality monitoring data show a range of short-duration hypoxic events occurring in shallow waters of the Bay at sub-daily to weekly temporal scales. The occurrence of fish kills has also been an obvious sign that illustrates the extent and impacts of a potentially larger hypoxia issue within the Chesapeake Bay ecosystem.

Contributions to understanding Bay health through citizen science are growing in the Chesapeake Bay region. Citizen monitoring can provide support for expanding data collection designed to better define the magnitude and extent of hypoxia beyond the traditional description of the dead zone. The combination of existing and growing sources of high quality dissolved oxygen data can lead to overcoming the challenges of providing estimates for total annual hypoxia in the tidal waters of Chesapeake Bay and provide a more comprehensive evaluation of overall Bay health.