Estimating Total Alkalinity in the Washington State Coastal Zone: Complexities and Surprising Utility for Ocean Acidification Research

Authors

Andrea J. Fassbender, Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, USA
Simone R. Alin, Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, USA
Richard A. Feely, Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, USA
Adrienne J. Sutton, Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, USA
Jan A. Newton, University of Washington
Robert H. Byrne, University of South FloridaFollow

Document Type

Article

Publication Date

2017

Keywords

Total alkalinity, Carbonate chemistry, Washington state, Seawater pH

Digital Object Identifier (DOI)

https://doi.org/10.1007/s12237-016-0168-z

Abstract

Evidence of ocean acidification (OA) throughout the global ocean has galvanized some coastal communities to evaluate carbonate chemistry variations closer to home. An impediment to doing this effectively is that, often, only one carbonate system parameter is measured at a time, while two are required to fully constrain the inorganic carbon chemistry of seawater. In order to leverage the abundant single-carbonate-parameter datasets in Washington State for more rigorous OA research, we have characterized an empirical relationship between total alkalinity (TA) and salinity (TA = 47.7 × S + 647; 1σ = ±17 μmol kg−1) for regional surface waters (≤25 m) that is robust in the salinity range from 20 to 35 for all seasons. The relationship was evaluated using 5 years of 3-h contemporaneous observations of salinity, carbon dioxide partial pressure (pCO2), and pH from a surface mooring on the outer coast of Washington. In situ pCO2 observations and salinity-based estimates of TA were used to calculate pH for comparison with in situ pH measurements. On average, the calculated pH values were 0.02 units lower than the measured pH values across multiple pH sensor deployments and showed extremely high fidelity in tracking the measured high-frequency pH variations. Our results indicate that the TA-salinity relationship will be a useful tool for expanding single-carbonate-parameter datasets in Washington State and quality controlling dual pCO2-pH time series.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Estuaries and Coasts, v. 40, p. 404-418

Scholar Commons Citation

Fassbender, Andrea J.; Alin, Simone R.; Feely, Richard A.; Sutton, Adrienne J.; Newton, Jan A.; and Byrne, Robert H., "Estimating Total Alkalinity in the Washington State Coastal Zone: Complexities and Surprising Utility for Ocean Acidification Research" (2017). Marine Science Faculty Publications. 1786.
https://digitalcommons.usf.edu/msc_facpub/1786