Sensitivity of the regional ocean acidification and carbonate system in Puget Sound to ocean and freshwater inputs

• Main Authors: Bianucci, Laura, Long, Wen, Khangaonkar, Tarang, Pelletier, G. J., Ahmed, Anise, Mohamedali, Teizeen, Roberts, Mindy, Figueroa-Kaminsky, Cristiana
• Format: Text
• Language: English
• Published: Western CEDAR 2018
• Subjects: Salish Sea; Puget Sound; numerical model; ocean acidification; ocean biogeochemistry; Fresh Water Studies; Life Sciences; Marine Biology; Natural Resources and Conservation; Terrestrial and Aquatic Ecology; Pacific; Ocean acidification
• Online Access: https://cedar.wwu.edu/ssec/2018ssec/allsessions/314; https://cedar.wwu.edu/cgi/viewcontent.cgi?article=2749&context=ssec

While ocean acidification was first investigated as a global phenomenon, coastal acidification has received significant attention in recent years, as its impacts have been felt by different socio-economic sectors (e.g., high mortality of shellfish larvae in aquaculture farms). As a region that connects land and ocean, the Salish Sea (consisting of Puget Sound and the Straits of Juan de Fuca and Georgia) receives inputs from many different sources (rivers, wastewater treatment plants, industrial waste treatment facilities, etc.), making these coastal waters vulnerable to acidification. Moreover, the lowering of pH in the Northeast Pacific Ocean also affects the Salish Sea, as more acidic waters get transported into the bottom waters of the straits and estuaries. Here, we use a numerical ocean model of the Salish Sea to improve our understanding of the carbonate system in Puget Sound; in particular, we studied the sensitivity of carbonate variables (e.g., dissolved inorganic carbon, total alkalinity, pH, saturation state of aragonite) to ocean and freshwater inputs. The model is the updated version of our FVCOM-ICM framework (Finite Volume Community Ocean Model coupled to the water-quality model CE-QUAL-ICM), now with carbonate-system and sediment modules. Sensitivity experiments altering concentrations at the open boundaries and freshwater sources indicate that not only ocean conditions entering the Strait of Juan de Fuca, but also the dilution of carbonate variables by freshwater sources, are key drivers of the carbonate system in Puget Sound. This work is an update from our presentation in the Salish Sea Conference 2016, showing the final results from our model experiments.