Journal Article

Storm-induced upwelling of high pCO2 waters onto the continental shelf of the western Arctic Ocean and implications for carbonate mineral saturation states

McNeil, Craig L., Juranek, Laurie W., Feely, Richard A., Morison, Jamie, Reisdorph, Stacey C., Ma, Jian, Pickart, Robert S., Byrne, Robert H., Easley, Regina A., Cross, Jessica N., Moore, G. W. K., Bahr, Frank, Elliot, Matthew M., Mathis, Jeremy T., Liu, Xuewu, Lichendorf, Trina

2012

Overview

The carbon system of the western Arctic Ocean is undergoing a rapid transition as sea ice extent and thickness decline. These processes are dynamically forcing the region, with unknown consequences for CO2 fluxes and carbonate mineral saturation states, particularly in the coastal regions where sensitive ecosystems are already under threat from multiple stressors. In October 2011, persistent wind‐driven upwelling occurred in open water along the continental shelf of the Beaufort Sea in the western Arctic Ocean. During this time, cold (<−1.2°C), salty (>32.4) halocline water—supersaturated with respect to atmospheric CO2 (pCO2 > 550 μatm) and undersaturated in aragonite (Ωaragonite < 1.0) was transported onto the Beaufort shelf. A single 10‐day event led to the outgassing of 0.18–0.54 Tg‐C and caused aragonite undersaturations throughout the water column over the shelf. If we assume a conservative estimate of four such upwelling events each year, then the annual flux to the atmosphere would be 0.72–2.16 Tg‐C, which is approximately the total annual sink of CO2 in the Beaufort Sea from primary production. Although a natural process, these upwelling events have likely been exacerbated in recent years by declining sea ice cover and changing atmospheric conditions in the region, and could have significant impacts on regional carbon budgets. As sea ice retreat continues and storms increase in frequency and intensity, further outgassing events and the expansion of waters that are undersaturated in carbonate minerals over the shelf are probable. Key Points Low pressure storm systems in the Arctic induce strong upwelling along the shelf Upwelling leads to large fluxes of CO2 out of the ocean Upwelling causes broad carbonate mineral suppression and undersaturation

• Publisher: Blackwell Publishing Ltd,American Geophysical Union,John Wiley & Sons, Inc
• Subject: Arctic Ocean / Biological oceanography / Carbon dioxide / Chemical oceanography / CO2 fluxes / Coastal zone / Continental shelves / Earth sciences / Earth, ocean, space / Exact sciences and technology / Ice cover / ocean acidification / Physical oceanography / Primary production / Sea ice / Upwelling / Water column