A novel method for determination of aragonite saturation state on the continental shelf of central Oregon using multi-parameter relationships with hydrographic data

We developed a multiple linear regression model to robustly determine aragonite saturation state (Omega(arag)) from observations of temperature and oxygen (R-2 = 0.987, RMS error 0.053), using data collected in the Pacific Northwest region in late May 2007. The seasonal evolution of Omega(arag) near central Oregon was evaluated by applying the regression model to a monthly (winter)/bi-weekly (summer) water-column hydrographic time-series collected over the shelf and slope in 2007. The Omega(arag) predicted by the regression model was less than 1, the thermodynamic calcification/dissolution threshold, over shelf/slope bottom waters throughout the entire 2007 upwelling season (May-November), with the Omega(arag) = 1 horizon shoaling to 30 m by late summer. The persistence of water with Omega(arag) < 1 on the continental shelf has not been previously noted and could have notable ecological consequences for benthic and pelagic calcifying organisms such as mussels, oysters, abalone, echinoderms, and pteropods. Citation: Juranek, L. W., R. A. Feely, W. T. Peterson, S. R. Alin, B. Hales, K. Lee, C. L. Sabine, and J. Peterson (2009), A novel method for determination of aragonite saturation state on the continental shelf of central Oregon using multi-parameter relationships with hydrographic data, Geophys. Res. Lett., 36, L24601, doi:10.1029/2009GL040778.