Samantha Siedlecki, University of Connecticut

Over the past 15 years, waters in the Gulf of Maine have taken up carbon dioxide (CO2) at a rate significantly slower than that observed in the open oceans due to a combination of the extreme warming experienced in the region and an increased presence of well-buffered Gulf Stream water [Salisbury and Johnson 2018]. The reduced uptake of CO2 by the shelves could also alter local acidification rate, which differ from the global rates. The intrusion of anthropogenic CO2 is not the only mechanism that can reduce Ωarag within coastal surface waters. Local processes like freshwater delivery, eutrophication, water column metabolism, and sediment interactions that drive variability on regional scales can also modify spatial variability in Ωarag [Cai et al. 2011; Siedlecki et al. 2017; Qi et al., 2017; Pilcher et al. 2018; Feely et al. 2008; 2018]. Global projections cannot resolve these local processes with resolution of a degree or more. Some high-resolution global projections have been developed which perform well in some coastal settings [Saba et al. 2016]. However, these simulations do not include regional biogeochemical processes described above which can amplify or dampen these global changes, particularly in coastal shelf regions. Our hypothesis is that a regionally downscaled projection for the east coast of the US can be used to evaluate the ability of the existing observational network to detect changes in ocean acidification relevant stressors for scallops and propose a process-based strategy for the network moving forward.