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Summer carbonate chemistry in the Dalton Polynya, East Antarctica


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Arroyo, MC, Shadwick, EH and Tilbrook, B 2019 , 'Summer carbonate chemistry in the Dalton Polynya, East Antarctica' , Journal of Geophysical Research: Oceans, vol. 124, no. 8 , pp. 5634-5653 , doi: 10.1029/2018JC014882.

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The carbonate chemistry in the Dalton Polynya in East Antarctica (115°–123°E) was investigated in summer 2014/2015 using high‐frequency underway measurements of CO2 fugacity (fCO2) and discrete water column measurements of total dissolved inorganic carbon (TCO2) and total alkalinity. Air‐sea CO2 fluxes indicate this region was a weak net source of CO2 to the atmosphere (0.7 ± 0.9 mmol C m−2 day−1) during the period of observation, with the largest degree of surface water supersaturation (ΔfCO2 = +45 μatm) in ice‐covered waters near the Totten Ice Shelf (TIS) as compared to the ice‐free surface waters in the Dalton Polynya. The seasonal depletion of mixed‐layer TCO2 (6 to 51 μmol/kg) in ice‐free regions was primarily driven by sea ice melt and biological CO2 uptake. Estimates of net community production (NCP) reveal net autotrophy in the ice‐free Dalton Polynya (NCP = 5–20 mmol C m−2 day−1) and weakly heterotrophic waters near the ice‐covered TIS (NCP = −4–0 mmol C m−2 day−1). Satellite‐derived estimates of chlorophyll a (Chl a) and sea ice coverage suggest that the early summer season in 2014/2015 was anomalous relative to the long‐term (1997–2017) record, with lower surface Chl a concentrations and a greater degree of sea ice cover during the period of observation; the implications for seasonal primary production and air‐sea CO2 exchange are discussed. This study highlights the importance of both physical and biological processes in controlling air‐sea CO2 fluxes and the significant interannual variability of the CO2 system in Antarctic coastal regions.

Item Type: Article
Authors/Creators:Arroyo, MC and Shadwick, EH and Tilbrook, B
Keywords: carbonate, Dalton Peninsula, Antarctica, CO2
Journal or Publication Title: Journal of Geophysical Research: Oceans
Publisher: Wiley-Blackwell Publishing Inc.
ISSN: 2169-9275
DOI / ID Number: 10.1029/2018JC014882
Copyright Information:

© 2019. The Authors. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivatives 4.0 International (CC BY-NC-ND 4.0) License, ( which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

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