Sea ice concentration impacts dissolved organic gases in the Canadian Arctic

• Published in: Biogeosciences
• Main Authors: Wohl, Charel, Jones, Anna E., Sturges, William T., Nightingale, Philip D., Else, Brent, Butterworth, Brian J., Yang, Ming-Xi
• Other Authors: Natural Environment Research Council (UK), Department for Business, Energy and Industrial Strategy (UK), Natural Sciences and Engineering Research Council of Canada, Agencia Estatal de Investigación (España)
• Format: Article in Journal/Newspaper
• Language: English
• Published: European Geosciences Union 2022
• Subjects: Arctic; Sea ice
• Online Access: http://hdl.handle.net/10261/263134; https://doi.org/10.5194/bg-19-1021-2022; https://doi.org/10.13039/501100011033; https://doi.org/10.13039/501100000038; https://doi.org/10.13039/501100000270; https://doi.org/10.13039/100011693

25 pages, 11 figures, supplement https://doi.org/10.5194/bg-19-1021-2022-supplement.-- Data availability: Data have been submitted to Polar Data Catalogue (https://www.polardata.ca/pdcsearch/), where the CCIN Reference number is 13249 and the DOI is https://doi.org/10.21963/13249 The marginal sea ice zone has been identified as a source of different climate-active gases to the atmosphere due to its unique biogeochemistry. However, it remains highly undersampled, and the impact of summertime changes in sea ice concentration on the distributions of these gases is poorly understood. To address this, we present measurements of dissolved methanol, acetone, acetaldehyde, dimethyl sulfide, and isoprene in the sea ice zone of the Canadian Arctic from the surface down to 60 m. The measurements were made using a segmented flow coil equilibrator coupled to a proton-transfer-reaction mass spectrometer. These gases varied in concentrations with depth, with the highest concentrations generally observed near the surface. Underway (3–4 m) measurements showed higher concentrations in partial sea ice cover compared to ice-free waters for most compounds. The large number of depth profiles at different sea ice concentrations enables the proposition of the likely dominant production processes of these compounds in this area. Methanol concentrations appear to be controlled by specific biological consumption processes. Acetone and acetaldehyde concentrations are influenced by the penetration depth of light and stratification, implying dominant photochemical sources in this area. Dimethyl sulfide and isoprene both display higher surface concentrations in partial sea ice cover compared to ice-free waters due to ice edge blooms. Differences in underway concentrations based on sampling region suggest that water masses moving away from the ice edge influences dissolved gas concentrations. Dimethyl sulfide concentrations sometimes display a subsurface maximum in ice -free conditions, while isoprene more reliably displays a subsurface ...