Air‐Sea CO 2 Flux Estimates in Stratified Arctic Coastal Waters: How Wrong Can We Be?

Lisa A. Miller, Tonya M. Burgers, William J. Burt, Mats A. Granskog, Tim N. Papakyriakou
2019 Geophysical Research Letters  
Summer near-surface seawater sampling in the Canadian Arctic revealed potential for significant errors (nearly 0.1 μmol·(m -2 s -1 )) in CO 2 fluxes calculated from measured air-sea CO 2 gradients. River runoff and sea ice melt strongly stratify these waters, often resulting in surface mixed layers only a few meters thick and isolated from waters sampled by shipboard underway systems. Samples collected with the underway system, rosette, and small boats exposed substantial near-surface gradients
more » ... in CO 2 partial pressure (pCO 2 ) over the top 7 m at many stations. Distributions of temperature, salinity, and fluorescence indicated that the sources of the CO 2 system gradients varied between stations, precluding simple corrections to align subsurface data with shallower conditions. Overall, the strong summertime sink of atmospheric CO 2 implied by the underway data was not supported by shallower data.
doi:10.1029/2018gl080099 fatcat:sct75n5gv5g2rimuhi4j37teoi