Coastal Ocean Acidification Along the Washington Coast Adjacent to the Salish Sea

• Main Author: Feely, Richard
• Format: Text
• Language: English
• Published: Western CEDAR 2022
• Subjects: British Columbia; Canada; Queen Charlotte; Ocean acidification
• Online Access: https://cedar.wwu.edu/ssec/2022ssec/allsessions/195; https://cedar.wwu.edu/context/ssec/article/3357/viewcontent/217_8ff9637401df4123b6f99046d4071200.pdf

The continental shelf waters off the west coast of North America are exposed to water with increasing concentrations of anthropogenic CO2 (Canthro) from exchanges with the atmosphere and the shoreward transport and mixing of upwelled water from the south and west. Hydrographic measurements were made offshore of the west coast of the United States and Canada on the RV Ronald H. Brown on the West Coast Ocean Acidification cruise in June and July of 2021 (WCOA2021). The primary goal of this WCOA2021 cruise was to measure the physics, chemistry, and biology of this region from Queen Charlotte Sound in British Columbia to southern California in order to develop a clearer understanding of the intersection of natural and anthropogenic ocean acidification, deoxygenation, and biogeochemical cycling processes in these waters. This region is a natural laboratory for studying the chemical and ecological impacts of ocean acidification and deoxygenation due to spring and summertime wind-driven upwelling of cold waters that are rich in re-mineralized carbon and nutrients and poor in oxygen. The upwelled nutrients drive intense cycling of organic matter that is created through photosynthesis in the surface ocean and degraded through biological respiration in subsurface habitats. We observed reductions in pH and decreases in aragonite saturation state of up to 0.1 and 0.2, respectively, relative to a linear mixing model for surface and subsurface waters due to the enhanced respiration processes in the subsurface waters off the coasts of Washington and Oregon where hypoxic conditions prevailed over much of the region. These conditions for dissolved oxygen, pH and aragonite saturation state in the subsurface waters were below critical thresholds for several marine species of importance to the California Current Ecosystem.