Oyster farming in Delaware is a crucial industry, bringing in $300,000 to $500,000 in sales every year. Oysters use calcium carbonate ions in the form of aragonite and calcite to form their shells. Ocean acidification can lead to a decrease in carbonate ions making forming these shells difficult. When aragonite saturation state falls below 3, calcifying organisms become stressed and when it drops below 1, their shells begin to dissolve. Therefore, measuring the aragonite saturation state yields crucial insight in to the suitability of habitats to suppo rt oyster growth. This project aimed to calculate the aragonite saturation state from seven sites within Delaware Inland Bays to determine t heir feasibility in supporting the establishment of oyster farms.
Monitoring was conducted biweekly from July to November 2020 and 2021 . Temperature, salinity, alkalinity and pH were determined using YSI methods. Using the SeaCarb program package in the R programming language, aragonite saturation state was calculated with the water quality parameters: temperature, salinity, alkalinity, and pH as inputs. In 2020, the aragonite saturation states were under saturated, with the average values of all sites remaining below a saturation state of 3. The highest registered average aragonite saturation value was 1.31 at the Redefer control site and the lowest value was 0.55 from the Bay City control site (Fig. 1) . These values do not meet the recommended saturation state for sustainable oyster farming . As salinity is the main factor influencing the aragonite saturation values, o yster variants which are tolerant to low salinity would be recommended for these sites. The 2021 data will expand on aragonite saturation trends in the Bay.