The Impact of Precipitation Events on Aquaculture Due to Coastal Acidification

The carbonate system in the coastal ocean is significantly more variable than in the open ocean. This is due to a lower buffering capacity and more severe changes in temperature, salinity, nutrient input, dissolved oxygen, and phytoplankton growth than the open ocean. Rain events have been shown to temporarily lower the aragonite saturation state for a period (hours to days). Aragonite saturation state is a predictor of how successful an oyster stock will be in terms of individual size and shell quality as well as recruitment. Duxbury harbor is located on the south shore of Massachusetts and is home to 29 oyster growers and $5 million industry. Autosamplers are deployed to collect high resolution surface water samples in Duxbury harbor before, during, and after rainstorms. These samples are then analyzed for pH, alkalinity, and total dissolved inorganic carbon. The aragonite saturation is calculated over the length of the storm to assess the extent of carbonate stress on the oysters. Preliminary results suggest that aragonite saturation is affected by freshwater input from a rainstorm. This could have implications on the aquaculture industry in Duxbury harbor as well as other sites with increased ocean acidification, warming temperatures, and more persistent diseases.