Type of Presentation

Oral

Session Title

Ocean Acidification in the Salish Sea

Description

Through survey cruises and moored time-series, we have observed the dynamic carbon cycle in various sub-basins of the southern Salish Sea since 2008. Areas of Puget Sound with restricted circulation, such as Hood Canal, may experience conditions of high pCO2, low pH, and low aragonite saturation state in deep waters throughout the year. Historically, the highest pCO2 and lowest pH and aragonite saturation states have been observed in early fall in Hood Canal.

Upwelling of dense, nutrient- and CO2-rich but oxygen-poor water along the coast provides the marine source for Puget Sound’s deep waters. We have previously estimated that marine waters entering Puget Sound via the Strait of Juan de Fuca are now corrosive 95% of the time, representing a 26% increase in frequency since the preindustrial era. Both river inputs and intense primary production in surface waters drive remineralization of organic matter in deep waters of Puget Sound basins, contributing to the exacerbation of corrosive conditions in waters below the stratified and productive surface waters. In addition, we estimate that regionally enhanced atmospheric CO2 content may result in an increased uptake of CO2 in the region.

Empirical relationships for reconstructing carbonate chemistry within Puget Sound have been created based on calibration data sets from coastal surveys, individual Puget Sound cruises, individual basins within Puget Sound, and the full Puget Sound data set (2008–2014). Here we compare their efficacy in reconstructing the evolution of carbonate system variables through seasons and across years on a profiling mooring in Hood Canal. In 2015 many features of the seasonal carbon cycle were accelerated relative to earlier years, as a result of the influence of the NE Pacific warm water anomaly. In southern Hood Canal, we saw the lowest estimated pH and aragonite saturation values in deep waters observed to date in Washington marine environments.

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Reconstructing carbonate chemistry in deep waters of the southern Salish Sea

2016SSEC

Through survey cruises and moored time-series, we have observed the dynamic carbon cycle in various sub-basins of the southern Salish Sea since 2008. Areas of Puget Sound with restricted circulation, such as Hood Canal, may experience conditions of high pCO2, low pH, and low aragonite saturation state in deep waters throughout the year. Historically, the highest pCO2 and lowest pH and aragonite saturation states have been observed in early fall in Hood Canal.

Upwelling of dense, nutrient- and CO2-rich but oxygen-poor water along the coast provides the marine source for Puget Sound’s deep waters. We have previously estimated that marine waters entering Puget Sound via the Strait of Juan de Fuca are now corrosive 95% of the time, representing a 26% increase in frequency since the preindustrial era. Both river inputs and intense primary production in surface waters drive remineralization of organic matter in deep waters of Puget Sound basins, contributing to the exacerbation of corrosive conditions in waters below the stratified and productive surface waters. In addition, we estimate that regionally enhanced atmospheric CO2 content may result in an increased uptake of CO2 in the region.

Empirical relationships for reconstructing carbonate chemistry within Puget Sound have been created based on calibration data sets from coastal surveys, individual Puget Sound cruises, individual basins within Puget Sound, and the full Puget Sound data set (2008–2014). Here we compare their efficacy in reconstructing the evolution of carbonate system variables through seasons and across years on a profiling mooring in Hood Canal. In 2015 many features of the seasonal carbon cycle were accelerated relative to earlier years, as a result of the influence of the NE Pacific warm water anomaly. In southern Hood Canal, we saw the lowest estimated pH and aragonite saturation values in deep waters observed to date in Washington marine environments.