CHARACTERIZING THE CARBONATE CHEMISTRY ENVIRONMENT IN THE CHESAPEAKE BAY: FOCUS ON SHELLFISH HATCHERIES

Oysters and clams are an essential part of our near-shore ecosystems and a vital part of life in coastal communities. Over the last few years Virginia hatcheries have experienced suppressed larval production for intermittent times during a production season. A water quality monitoring program was implemented between academic and State agency partners in Virginia and New Hampshire along with six shellfish hatcheries. This extension and outreach effort, initiated in 2012, provided the training and resources for each hatchery to discretely monitor numerous water quality parameters. In 2014, the program was expanded to include the monitoring of carbonate chemistry. More specifically, a parameter that is particularly useful for the shellfish industry is the carbonate mineral saturation state for aragonite (Ω). Low Ω values can suppress larvae production success at our hatcheries. A pilot project was implemented with a robust state-of-the art system that continuously monitors the partial pressure of carbon dioxide (pCO₂). This system was developed in partnership with personnel from the University of New Hampshire and implemented at one of the Virginia shellfish hatcheries. pCO2 data was used in conjunction with salinity and temperature to model Ω at the hatcheries. This program was expanded in 2016 to include five hatcheries. From our data it is apparent that factors other than ocean acidification are very important for understanding carbonate chemistry in dynamic estuarine environments. Ω fluctuates diurnally and seasonally and are influenced by factors such as algae activity, weather events, and likely sediment interactions.